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Build a Photo Sharing App in a Day Step by Step Guide for Android www.stackmob.com
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SnapStack Android Bootcamp
Welcome! This series is focused on the creation of SnapStack, a location-based photo sharing app for Android phones. We’ll walk through the entire process of building SnapStack, from the initial idea and design to submitting to the Google Play Store. Along the way, we’ll demonstrate the usefulness of the StackMob platform and highlight the benefits of incorporating StackMob into your next project. Download SnapStack from the Google Play Store. | Download the full project source code.
Who should read this tutorial? This series is aimed at developers of all skill levels who are looking for an example app that showcases the features of the StackMob platform. The goal is to illustrate how easy it is to build and release to the Google Play Store using StackMob as the backend of your app. The pace of this tutorial will start out slow and ramp up quickly. It’s recommended that you have a basic understanding of Java and the Eclipse IDE.
Prerequisites • We’ll be using the Android Developer Tools v21 and our mininum SDK will be Android 4.0. • If you’re not already a StackMob customer, sign up for free.
Idea Our app, SnapStack, will be a simple photo taking app. Users will be able to snap and share photos, view photos nearby both in a feed and on a map, and post comments. Download SnapStack from the Google Play Store.
What we’ll cover Creating an app like SnapStack requires a fair amount of setup. In this tutorial, we’ll be adding all of the ingredients necessary to construct our app. We’ll create an Android Eclipse project as well as a StackMob app. The next part of this tutorial will cover adding the necessary SDKs and configurations to our project.
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SnapStack Android Bootcamp
Part 1: Setup Using StackMob We’ll be using many features provided by the StackMob Android SDK and the StackMob Marketplace. The modules in the Marketplace are services that can be quickly installed and incorporated into your app. Our app will utilize the following modules from the StackMob Marketplace:
Access Controls: The access controls module will give us greater control over schema permissions. API: We’ll use the API to perform CRUD operations on our data. GeoQueries: The geoqueries module will enable our app to be powered by GPS location data.
S3: To integrate photo storage into our app, we’ll use the S3 module.
Download ADT If you haven’t done so yet, visit the Android developer center to download and install the ADT bundle.
Create a new Android project 1. Open up ADT and select a directory for your workspace. The default is ~/Documents/workspace. 2. Choose File > New > Android Application Project.
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3. Enter “SnapStack” for the name of the application, and “SnapStackAndroid” for the project name. Enter a unique identifier for your package name. Set your minimum Android SDK to 3.0. Set the project to compile with the latest Google APIs. Click next.
4. Make sure “Create Activity” is selected. Click next twice.
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5. Choose “Blank Activity” and click next.
6. Enter “MainActivity” for the Activity name and “activity_ main” for the Layout name. Click finish.
Create a StackMob application Instead of building our own backend server (which would take weeks of work), we can take advantage of the StackMob platform immediately. To do this, we’ll create an app on StackMob, which will come complete with Development and Production Keys, API requests and some Marketplace modules preinstalled, all for free!
1. Head over to StackMob and login to your Dashboard (if you don’t have an account, create one first). Click “Create New App,” in the top right corner.
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2. Create an app called “snapstack” and choose Android as your platform. Click next.
3. Follow the setup instructions for importing the StackMob Android SDK.
Setting up S3 Follow the tutorial to create and add S3 credentials to your StackMob app.
Creating the data model Our app will have a straightforward data model, consisting of three schemas: User, Snap and Comment. • The User schema is automatically created for you when you create an app on StackMob. It is assumed to be the schema for storing your user objects as well as for password management, etc. • A snap is created by a user, and contains the image taken, a relationship to the User who created it, as well as the geo location of where it was created. • Users can make comments on snaps. A comment has a relationship to the User who created it, the text of the comment, and the relationship to its parent Snap object. 1. Navigate to the Schema Configuration tab in your Dashboard. 2. Click “Edit” next to the User schema. Add the following attributes: • A string attribute called email • A binary attribute called photo Save the User schema. In the User schema, set the “Forgot Password Email Field” to email.
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3. Click Schema Configuration from the menu. Click “Create New Schema.” Create a schema called “snap” and add the following attributes: • A binary attribute called photo • A geopoint attribute called location
4. StackMob allows you to manage schema permissions using the Access Controls module. Edit the permissions for this schema: • Set the create permission level to “Allow to any logged in user” • Set the read permission level to “Allow to any logged in user” • Set the edit permission level to “Allow to sm_owner (object owner)” • Set the delete permission level to “Allow to sm_owner (object owner)” Save the Snap schema.
5. Create another schema called “comment” and add the following attribute: • A String attribute called text Edit the permissions to match those in the “snap” schema. Add a relationship called “snap” with the related object set to “snap.” Make it a one-to-one relationship. Add another one-to-one relationship to “user,” called “creator.”
6. Go back and edit the “snap” schema. Add a relationship called “comments” and set the related object to “comment.” Make it a one-to-many relationship. Add a one-to-one relationship to “user,” called “creator.”
Setting up Google Maps Our app utilizes Google Maps, which requires Google Play Services to be installed. Visit the Google tutorial for Google Maps Android API v2. Follow the guide up until the last section, “Add a Map.”
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Creating a User model We’ll add a class named “User” to our project that subclasses StackMobUser. StackMobUser is a specialized subclass of StackMobModel meant to represent a user of your app. Like StackMobModel, it’s meant to be subclassed with whatever data you want to store with your user. Create a file, “User.java,” and add the following code: package com.stackmob.snapstack; import com.stackmob.sdk.api.StackMobFile; import com.stackmob.sdk.model.StackMobUser; public class User extends StackMobUser { private String email; private StackMobFile photo; public User(String username, String password, String email) { super(User.class, username, password); this.email = email; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public StackMobFile getPhoto() { return photo; } public void setPhoto(StackMobFile photo) { this.photo = photo; } }
Creating a Snap model To create and save snaps we’ll create a class named “Snap,” which will subclass StackMobModel. Add a new class called Snap.java, with the following code: package com.stackmob.snapstack; import com.stackmob.sdk.api.StackMobFile; import com.stackmob.sdk.api.StackMobGeoPoint; import com.stackmob.sdk.model.StackMobModel; public class Snap extends StackMobModel {
private User creator; private StackMobGeoPoint location;
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private StackMobFile photo;
public Snap(User creator, StackMobGeoPoint location) { super(Snap.class);
this.creator = creator; this.location = location;
} public User getCreator() { return creator; } public void setCreator(User creator) { this.creator = creator; } public StackMobGeoPoint getLocation() { return location; } public void setLocation(StackMobGeoPoint location) { this.location = location; } public void setPhoto(StackMobFile photo) { this.photo = photo; } public StackMobFile getPhoto() { return photo; } }
Creating a comment model Our “Comment” class will also subclass StackMobModel. Add a new class called Comment.java, with the following code:
package com.stackmob.snapstack; import com.stackmob.sdk.model.StackMobModel; public class Comment extends StackMobModel {
private User creator; private String text; private Snap snap;
public Comment(User creator, String text, Snap snap) { super(Comment.class); }
this.creator = creator; this.text = text; this.snap = snap;
public User getCreator() { return creator;
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} public void setCreator(User creator) { this.creator = creator; } public String getText() { return text; } public void setText(String text) { this.text = text; } public Snap getSnap() { return snap; } public void setSnap(Snap snap) { this.snap = snap; } }
Adding strings SnapStack makes use of many string constants throughout the app. Edit res/values/strings.xml with the following strings: SnapStack Settings Hello world! Sign In Sign Up For SnapStack Forgot Your Password? Enter your username Enter your password Enter your email address Join SnapStack Make profile picture Choose your profile picture Show Map Show List This is the profile picture This is an image Share Photo Comments Sign Out Delete Type your comment here Share Comment Comment Email a temporary password Enter your username, and we\’ll email you a temporary password. Enter temporary password
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Adding 3rd party libraries Download Android Pull to Refresh and add it to your project:
1. Right-click the project and choose “Import…”
2. Choose “Existing Android Code Into Workspace” as an import source.
3. Select only the library and click “Finish.”Make sure you have “Copy projects into Workspace” checked.
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4. Right-click the project, and select “Properties”: 5. Navigate to the Android menu and click “Add…”:
6. Select the library and click OK.
Download Android Universal Image Loader and add it to your project. Copy the jar file into your libs folder.
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Adding the necessary assets We’ve included the assets needed for this project, including drawables and XML layouts. Download and unzip the assets for this project.
1. Drag the entire drawable folder into the project, under the res folder. Make sure you have “Copy files” selected.
2. Copy the contents of the drawable-hdpi folder into the corresponding directory in your project. Make sure you have “Copy files” selected.
3. Copy the contents of the layout folder into the corresponding directory in your project. Make sure you have “Copy files” selected.
4. Finally, copy the contents of the menu folder into the corresponding directory in your project. Make sure you have “Copy files” selected.
SnapStack Application In our app we’ll create an Application class. This is where we’ll store our User object, for use throughout the app. Create a class called SnapStackApplication.java. Make sure it subclasses the Application class.
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package com.stackmob.snapstack; import android.app.Application; import android.content.Context; import import import import
com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator; com.nostra13.universalimageloader.core.ImageLoader; com.nostra13.universalimageloader.core.ImageLoaderConfiguration; com.nostra13.universalimageloader.core.assist.QueueProcessingType;
public class SnapStackApplication extends Application {
private User user; private Snap snap;
@Override public void onCreate() { super.onCreate(); initImageLoader(getApplicationContext()); } public User getUser() { return user; } public void setUser(User user) { this.user = user; } public Snap getSnap() { return snap; } public void setSnap(Snap snap) { this.snap = snap; } public static void initImageLoader(Context context) { ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder( context).threadPriority(Thread.NORM_PRIORITY - 2) .denyCacheImageMultipleSizesInMemory() .discCacheFileNameGenerator(new Md5FileNameGenerator()) .tasksProcessingOrder(QueueProcessingType.LIFO).enableLogging() .build(); // Initialize ImageLoader with configuration. ImageLoader.getInstance().init(config); } }
This application class contains two instance variables, user and snap, as well as getters and setters for both of them. We’ll use these two extensively throughout the project. We’ll also be utilizing ImageLoader throughout the project, and we initialize it here.
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AndroidManifest Update your project’s AndroidManifest.xml file to look like this:
The project now includes all the necessary permissions and activity references for our app.
Sanity check Be sure to build your project to double check that it is free of errors.
Congrats! We’ve reached the end of Part 1 and have completed the majority of the grunt work. All the pieces are in place: StackMob, S3 integration, XML layouts and more. We can focus on simply the code from here on out. In Part 2 , we’ll focus on creating and uploading Snaps, as well as the profile and map view.
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SnapStack Android Bootcamp
Part 2 What we’ll cover In this part we’ll build the sign up/sign in flow for the app, allowing users to create profiles on SnapStack. We’ll also implement forgot password functionality in our app.
Creating the MasterActivity class Create a class that extends Activity, named MasterActivity.java. Most of our app will run through MasterActivity. For now, we won’t add any logic behind it: package com.stackmob.snapstack; import android.app.Activity; import android.os.Bundle; public class MasterActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_master); }
}
The signup flow Let’s build out the signup flow for SnapStack. Our signup process will be straightforward: we’ll have users create accounts by providing a username, password and email. We’ll also require users to upload a profile picture. For photos, we’ll make use of the standard Android Camera library. Users will have the option to take a photo or select from their gallery, and afterwards, crop the photo into a square. Add the following classes, which we’ve borrowed from this image cropping example on Github. CropOption.java:
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package com.stackmob.snapstack; import android.content.Intent; import android.graphics.drawable.Drawable; public class CropOption { public CharSequence title; public Drawable icon; public Intent appIntent; }
CropOptionAdapter.java: package com.stackmob.snapstack; import java.util.ArrayList; import import import import import import import
android.content.Context; android.view.LayoutInflater; android.view.View; android.view.ViewGroup; android.widget.ArrayAdapter; android.widget.ImageView; android.widget.TextView;
public class CropOptionAdapter extends ArrayAdapter { private ArrayList mOptions; private LayoutInflater mInflater; public CropOptionAdapter(Context context, ArrayList options) { super(context, R.layout.crop_selector, options); mOptions = options; mInflater = LayoutInflater.from(context); } @Override public View getView(int position, View convertView, ViewGroup group) { if (convertView == null) convertView = mInflater.inflate(R.layout.crop_selector, null); CropOption item = mOptions.get(position); if (item != null) { ((ImageView) convertView.findViewById(R.id.iv_icon)).setImageDrawable(item. icon); ((TextView) convertView.findViewById(R.id.tv_name)).setText(item.title); return convertView; } return null; } }
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Next, add an Activity named ChoosePhotoActivity, with the following code: package com.stackmob.snapstack; import import import import
java.io.ByteArrayOutputStream; java.io.File; java.util.ArrayList; java.util.List;
import import import import import import import import import import import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder; android.content.ActivityNotFoundException; android.content.ComponentName; android.content.DialogInterface; android.content.Intent; android.content.pm.ResolveInfo; android.graphics.Bitmap; android.graphics.BitmapFactory; android.graphics.drawable.BitmapDrawable; android.net.Uri; android.os.Bundle; android.os.Environment; android.provider.MediaStore; android.view.View; android.widget.ArrayAdapter; android.widget.Button; android.widget.ImageView; android.widget.Toast;
import com.stackmob.sdk.api.StackMobFile; import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; public class ChoosePhotoActivity extends Activity {
private private private private private
SnapStackApplication snapStackApplication; Uri imageCaptureUri; ImageView choose_photo_imageview; Button choose_photo_button; ProgressDialog progressDialog;
private static final int PICK_FROM_CAMERA = 1; private static final int CROP_FROM_CAMERA = 2; private static final int PICK_FROM_FILE = 3;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_choose_photo); snapStackApplication = (SnapStackApplication) getApplication(); final String[] items = new String[] { “Take from camera”, “Select from gallery” }; ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.select_dialog_item, items); AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Select Image”); builder.setAdapter(adapter, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int item) { // pick from // camera if (item == 0) {
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Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
imageCaptureUri = Uri.fromFile(new File(Environment .getExternalStorageDirectory(), “tmp_avatar_” + String.valueOf(System.currentTimeMillis()) + “.jpg”)); intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageCaptureUri); try {
intent.putExtra(“return-data”, true);
startActivityForResult(intent, PICK_FROM_CAMERA); } catch (ActivityNotFoundException e) { e.printStackTrace(); } } else { // pick from file Intent intent = new Intent();
intent.setType(“image/*”); intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, “Complete action using”), PICK_FROM_FILE); } } });
final AlertDialog dialog = builder.create();
choose_photo_button = (Button) findViewById(R.id.choose_photo_button); choose_photo_button.setEnabled(false); choose_photo_imageview = (ImageView) findViewById(R.id.choose_photo_imageview); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_ avatar); choose_photo_imageview.setImageBitmap(bitmap); choose_photo_imageview.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { dialog.show(); } }); choose_photo_button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { progressDialog = ProgressDialog.show( ChoosePhotoActivity.this, “Uploading photo”, “Uploading your profile pic”, true); Bitmap bitmap = ((BitmapDrawable) choose_photo_imageview. getDrawable()).getBitmap(); ByteArrayOutputStream stream = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream); byte[] image = stream.toByteArray(); User user = snapStackApplication.getUser(); user.setPhoto(new StackMobFile(“image/jpeg”, “profile_picture.jpg”, image)); user.save(new StackMobModelCallback() { @Override
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public void success() { progressDialog.dismiss(); int callingActivity = getIntent().getIntExtra(“calling_ activity”, 0); if (callingActivity == 666) { setResult(RESULT_OK, null); finish(); } else if (callingActivity == 333) { Intent intent = new Intent( ChoosePhotoActivity.this, MasterActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); finish(); } } @Override public void failure(StackMobException e) { progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog. Builder(ChoosePhotoActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error saving your photo.”); AlertDialog dialog = builder.create(); dialog.show(); } }); } }); } }); dialog.show(); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode != RESULT_OK) return; switch (requestCode) { case PICK_FROM_CAMERA: doCrop(); break; case PICK_FROM_FILE: imageCaptureUri = data.getData(); doCrop(); break;
case CROP_FROM_CAMERA:
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Bundle extras = data.getExtras();
if (extras != null) { Bitmap photo = extras.getParcelable(“data”); choose_photo_imageview.setImageBitmap(photo); choose_photo_button.setEnabled(true); }
File f = new File(imageCaptureUri.getPath());
if (f.exists()) f.delete(); break; } } private void doCrop() { final ArrayList cropOptions = new ArrayList();
Intent intent = new Intent(“com.android.camera.action.CROP”); intent.setType(“image/*”);
List list = getPackageManager().queryIntentActivities( intent, 0);
int size = list.size();
if (size == 0) { Toast.makeText(this, “Can not find image crop app”, Toast.LENGTH_SHORT).show(); return; } else { intent.setData(imageCaptureUri);
intent.putExtra(“outputX”, 200); intent.putExtra(“outputY”, 200); intent.putExtra(“aspectX”, 1); intent.putExtra(“aspectY”, 1); intent.putExtra(“scale”, true); intent.putExtra(“return-data”, true);
if (size == 1) { Intent i = new Intent(intent); ResolveInfo res = list.get(0); i.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name)); startActivityForResult(i, CROP_FROM_CAMERA); } else { for (ResolveInfo res : list) { final CropOption co = new CropOption(); co.title = getPackageManager().getApplicationLabel( res.activityInfo.applicationInfo); co.icon = getPackageManager().getApplicationIcon( res.activityInfo.applicationInfo); co.appIntent = new Intent(intent); co.appIntent .setComponent(new ComponentName( res.activityInfo.packageName, res.activityInfo.name));
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cropOptions.add(co); } CropOptionAdapter adapter = new CropOptionAdapter( getApplicationContext(), cropOptions); AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Choose Crop App”); builder.setAdapter(adapter, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int item) { startActivityForResult( cropOptions.get(item). appIntent, CROP_FROM_CAMERA); } }); builder.setOnCancelListener(new DialogInterface.OnCancelListener() { @Override public void onCancel(DialogInterface dialog) { if (imageCaptureUri != null) { getContentResolver().delete(imageCaptureUri, null, null); imageCaptureUri = null; } } }); AlertDialog alert = builder.create(); alert.show(); } } } }
The doCrop method makes use of the CropOption and CropOptionAdapter classes. For more information, check out this blog post explaining the code. Once a photo is chosen, we save it to StackMob and present MasterActivity. Finally, add an Activity named SignUpActivity: package com.stackmob.snapstack; import import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.AlertDialog.Builder; android.app.ProgressDialog; android.content.Context; android.content.Intent; android.os.Bundle; android.os.Handler; android.view.View; android.view.inputmethod.InputMethodManager; android.widget.Button; android.widget.EditText;
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import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; public class SignUpActivity extends Activity {
private private private private private private private private
SnapStackApplication snapStackApplication; EditText username_edittext; EditText password_edittext; EditText email_edittext; Button join_button; ProgressDialog progressDialog; Handler handler = new Handler(); User user;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_signup);
snapStackApplication = (SnapStackApplication) getApplication();
// Find our views username_edittext = (EditText) findViewById(R.id.username_edittext); password_edittext = (EditText) findViewById(R.id.password_edittext); email_edittext = (EditText) findViewById(R.id.email_edittext); join_button = (Button) findViewById(R.id.join_button);
join_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) { InputMethodManager imm = (InputMethodManager)getSystemService(Context. INPUT_METHOD_SERVICE); imm.hideSoftInputFromWindow(username_edittext.getWindowToken(), 0); imm.hideSoftInputFromWindow(password_edittext.getWindowToken(), 0); imm.hideSoftInputFromWindow(email_edittext.getWindowToken(), 0); progressDialog = ProgressDialog.show( SignUpActivity.this, “Signing up”, “Signing up for SnapStack”, true);
String username = username_edittext.getText().toString().trim(); String password = password_edittext.getText().toString().trim(); String email = email_edittext.getText().toString().trim();
if (foundError(username, password, email)) { progressDialog.dismiss(); return; }
User user = new User(username, password, email);
snapStackApplication.setUser(user); user.save(new StackMobModelCallback() { @Override public void success() { handler.post(new UserLogin()); } @Override public void failure(StackMobException e) {
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progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder( SignUpActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error signing up.”); AlertDialog dialog = builder.create(); dialog.show(); } }); } }); } }); }
public boolean foundError(String username, String password, String email) {
Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Oops”); builder.setCancelable(true); if (username.equals(“”)) { builder.setMessage(“Don’t forget to enter a username!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } else if (password.equals(“”)) { builder.setMessage(“Don’t forget to enter a password!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } else if (email.equals(“”)) { builder.setMessage(“Don’t forget to enter an email”); AlertDialog dialog = builder.create(); dialog.show(); return true; } else if (!android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches()) { builder.setMessage(“Please enter a valid email address.”); AlertDialog dialog = builder.create(); dialog.show(); return true; } return false; } private class UserLogin implements Runnable{ public UserLogin(){ }
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public void run(){ user = snapStackApplication.getUser(); user.login(new StackMobModelCallback() { @Override public void success() { progressDialog.dismiss(); snapStackApplication.setUser(user); Intent intent = new Intent(SignUpActivity.this, ChoosePhotoActivity.class); intent.putExtra(“calling_activity”, 333); startActivity(intent); finish(); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder( SignUpActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error logging in.”); AlertDialog dialog = builder.create(); dialog.show(); } }); } }); } }
The signup view accepts a username/password/email combo and creates an account for the user. We do this by creating a new User object and calling save on it. When the save is successful, we use a Handler to call the UserLogin runnable, which in its run method signs the User in. The foundError method checks for any empty or incorrect fields and notifies the user. If the save is successful, we present the ChoosePhotoActivity.
Implementing forgot password It’s a good idea to have a way for a user to recover their account, in case they ever lose their password. StackMob provides this feature with all User schemas. Earlier, we specified what field to use for the forgot password email. With the Android SDK, we can call a method that will trigger the process to allow the user to reclaim their account.
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First, create an Activity named ChangePasswordActivity, and add the following code: package com.stackmob.snapstack; import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder; android.content.Context; android.content.Intent; android.os.Bundle; android.view.View; android.view.inputmethod.InputMethodManager; android.widget.Button; android.widget.EditText;
public class ChangePasswordActivity extends Activity { private SnapStackApplication snapStackApplication; private EditText username_edittext; private EditText temporary_password_edittext; private EditText password_edittext; private Button signin_button; private ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_change_password); snapStackApplication = (SnapStackApplication) getApplication(); // Find our views username_edittext = (EditText) findViewById(R.id.username_edittext); password_edittext = (EditText) findViewById(R.id.password_edittext); temporary_password_edittext = (EditText) findViewById(R.id.temporary_password_ edittext); signin_button = (Button) findViewById(R.id.signin_button); signin_button.setOnClickListener(new View.OnClickListener() {
SERVICE);
public void onClick(View v) { InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_
imm.hideSoftInputFromWindow(username_edittext.getWindowToken(), 0); imm.hideSoftInputFromWindow(temporary_password_edittext.getWindowToken(), 0); imm.hideSoftInputFromWindow(password_edittext.getWindowToken(), 0); progressDialog = ProgressDialog.show( ChangePasswordActivity.this, “Signing in”, “Signing into SnapStack”, true); String username = username_edittext.getText().toString().trim(); String temp = temporary_password_edittext.getText().toString().trim(); String password = password_edittext.getText().toString().trim(); if (foundError(username, password)) { progressDialog.dismiss(); return; }
User user = new User(username, temp, null);
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snapStackApplication.setUser(user); user.loginResettingTemporaryPassword(password,new StackMobModelCallback() { @Override public void success() {
progressDialog.dismiss(); Intent intent = new Intent( ChangePasswordActivity.this, MasterActivity.class); startActivity(intent); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder(ChangePasswordActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error signing in.”); AlertDialog dialog = builder.create(); dialog.show(); } }); } }); } }); } public boolean foundError(String username, String password) { Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Oops”); builder.setCancelable(true); if (username.equals(“”)){ builder.setMessage(“Don’t forget to enter a username!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } else if (password.equals(“”)){ builder.setMessage(“Don’t forget to enter a password!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } return false; } }
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The activity contains a special sign in flow which allows the user to enter the temporary password, along with a new password. The method loginResettingTemporaryPassword makes this happen seamlessly. On a successful call, the user is signed into the master activity. Next, add the Activity ForgotPasswordActivity: package com.stackmob.snapstack; import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder; android.content.Intent; android.os.Bundle; android.view.View; android.widget.Button; android.widget.EditText;
import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; import com.stackmob.sdk.model.StackMobUser; public class ForgotPasswordActivity extends Activity { private EditText username_edittext; private Button forgot_password_button; private ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_forgot_password); username_edittext = (EditText) findViewById(R.id.username_edittext); forgot_password_button = (Button) findViewById(R.id.forgot_password_button); forgot_password_button.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View arg0) { String username = username_edittext.getText().toString(); if (username.trim().length() != 0){ progressDialog = ProgressDialog.show( ForgotPasswordActivity.this, “Saving”, “Sending email”, true); StackMobUser.sentForgotPasswordEmail(username, new StackMobModelCallback() { @Override public void success() { progressDialog.dismiss(); Intent intent = new Intent(ForgotPasswordActivity.this, ChangePasswordActivity.class); startActivity(intent); } @Override public void failure(StackMobException e) { progressDialog.dismiss();
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runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog. Builder( ForgotPasswordActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“Unable to recover password.”); AlertDialog dialog = builder. create(); dialog.show(); } }); } }); } } }); }
This is where users enter their username and request a temporary password. The sentForgotPasswordEmail method causes a temporary password to be sent to the user via email. That password is valid for 24 hours.
SignInActivity Create a new Activity named SignInActivity.java, with the following code: package com.stackmob.snapstack; import import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.AlertDialog.Builder; android.app.ProgressDialog; android.content.Context; android.content.Intent; android.os.Bundle; android.view.View; android.view.inputmethod.InputMethodManager; android.widget.Button; android.widget.EditText; android.widget.TextView;
import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; public class SignInActivity extends Activity {
private private private private private private private
SnapStackApplication snapStackApplication; EditText username_edittext; EditText password_edittext; Button signin_button; TextView forgot_password; ProgressDialog progressDialog; User user;
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@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_signin);
snapStackApplication = (SnapStackApplication) getApplication();
// Find our views username_edittext = (EditText) findViewById(R.id.username_edittext); password_edittext = (EditText) findViewById(R.id.password_edittext); signin_button = (Button) findViewById(R.id.signin_button); forgot_password = (TextView) findViewById(R.id.forgot_password); forgot_password.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Intent intent = new Intent( SignInActivity.this, ForgotPasswordActivity.class); startActivity(intent); } }); signin_button.setOnClickListener(new View.OnClickListener() {
SERVICE);
public void onClick(View v) { InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_
imm.hideSoftInputFromWindow(username_edittext.getWindowToken(), 0); imm.hideSoftInputFromWindow(password_edittext.getWindowToken(), 0); progressDialog = ProgressDialog.show( SignInActivity.this, “Signing in”, “Signing into SnapStack”, true); String username = username_edittext.getText().toString().trim(); String password = password_edittext.getText().toString().trim(); if (foundError(username, password)) { progressDialog.dismiss(); return; }
user = new User(username, password, null);
user.login(new StackMobModelCallback() { @Override public void success() {
progressDialog.dismiss(); snapStackApplication.setUser(user);
Intent intent = new Intent( SignInActivity.this, MasterActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); finish(); }
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@Override public void failure(StackMobException e) { progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder(SignInActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error signing in.”); AlertDialog dialog = builder.create(); dialog.show(); } }); } }); } }); } public boolean foundError(String username, String password) { Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Oops”); builder.setCancelable(true); if (username.equals(“”)){ builder.setMessage(“Don’t forget to enter a username!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } else if (password.equals(“”)){ builder.setMessage(“Don’t forget to enter a password!”); AlertDialog dialog = builder.create(); dialog.show(); return true; } return false; } }
The SignInActivity accepts a username and a password; the login attempts to sign in the user. Our helper method, foundError, notifies the user if they’re missing their username or password. We present the option to recover password if necessary, linking to ForgotPasswordActivity. If the sign in is successful, we present MasterActivity; if not, we present an error dialog.
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Adding GPSTracker Our app will leverage the User’s location to find Snaps nearby, and to add geopoints to the Snaps they upload. Add a class named GPSTracker.java: package com.stackmob.snapstack; import import import import import import import import import import import import
android.app.AlertDialog; android.app.Service; android.content.Context; android.content.DialogInterface; android.content.Intent; android.location.Location; android.location.LocationListener; android.location.LocationManager; android.os.Bundle; android.os.IBinder; android.provider.Settings; android.util.Log;
public class GPSTracker extends Service implements LocationListener { private final Context mContext; // flag for GPS status boolean isGPSEnabled = false; // flag for network status boolean isNetworkEnabled = false; // flag for GPS status boolean canGetLocation = false; Location location; // location double latitude; // latitude double longitude; // longitude // The minimum distance to change Updates in meters private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters // The minimum time between updates in milliseconds private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute // Declaring a Location Manager protected LocationManager locationManager; public GPSTracker(Context context) { this.mContext = context; getLocation(); } public Location getLocation() { try { locationManager = (LocationManager) mContext .getSystemService(LOCATION_SERVICE); // getting GPS status isGPSEnabled = locationManager .isProviderEnabled(LocationManager.GPS_PROVIDER); // getting network status isNetworkEnabled = locationManager .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
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if (!isGPSEnabled && !isNetworkEnabled) { // no network provider is enabled } else { this.canGetLocation = true; // First get location from Network Provider if (isNetworkEnabled) { locationManager.requestLocationUpdates( LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this); Log.d(“Network”, “Network”); if (locationManager != null) { location = locationManager .getLastKnownLocation(LocationManager.NETWORK_PROVIDER); if (location != null) { latitude = location.getLatitude(); longitude = location.getLongitude(); } } } // if GPS Enabled get lat/long using GPS Services if (isGPSEnabled) { if (location == null) { locationManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this); Log.d(“GPS Enabled”, “GPS Enabled”); if (locationManager != null) { location = locationManager .getLastKnownLocation(LocationManager.GPS_PROVIDER); if (location != null) { latitude = location.getLatitude(); longitude = location.getLongitude(); } } } } } } catch (Exception e) { e.printStackTrace(); } }
return location;
/** * Stop using GPS listener * Calling this function will stop using GPS in your app * */ public void stopUsingGPS(){ if(locationManager != null){ locationManager.removeUpdates(GPSTracker.this); } } /** * Function to get latitude * */ public double getLatitude(){ if(location != null){ latitude = location.getLatitude(); } // return latitude
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}
return latitude;
/** * Function to get longitude * */ public double getLongitude(){ if(location != null){ longitude = location.getLongitude(); }
}
// return longitude return longitude;
/** * Function to check GPS/wifi enabled * @return boolean * */ public boolean canGetLocation() { return this.canGetLocation; } /** * Function to show settings alert dialog * On pressing Settings button will lauch Settings Options * */ public void showSettingsAlert(){ AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext); // Setting Dialog Title alertDialog.setTitle(“GPS is settings”); // Setting Dialog Message alertDialog.setMessage(“GPS is not enabled. Do you want to go to settings menu?”); // On pressing Settings button alertDialog.setPositiveButton(“Settings”, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog,int which) { Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); mContext.startActivity(intent); } }); // on pressing cancel button alertDialog.setNegativeButton(“Cancel”, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } });
}
// Showing Alert Message alertDialog.show();
@Override public void onLocationChanged(Location location) { } @Override public void onProviderDisabled(String provider) { } @Override public void onProviderEnabled(String provider) { }
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@Override public void onStatusChanged(String provider, int status, Bundle extras) { } @Override public IBinder onBind(Intent arg0) { return null; } }
We’ll utilize this Service to handle all of our location needs. For more information, check out this tutorial.
Editing MainActivity Let’s add the logic for our main view. Edit MainActivity to look like this: package com.stackmob.snapstack; import java.util.List; import import import import import import import
android.app.Activity; android.app.ProgressDialog; android.content.Intent; android.os.Bundle; android.view.View; android.widget.Button; android.widget.Toast;
import import import import
com.stackmob.android.sdk.common.StackMobAndroid; com.stackmob.sdk.api.StackMob; com.stackmob.sdk.callback.StackMobQueryCallback; com.stackmob.sdk.exception.StackMobException;
public
class MainActivity extends Activity { private Button sign_up; private Button sign_in; private SnapStackApplication snapStackApplication;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); StackMobAndroid.init(getApplicationContext(), 0, “YOUR_PUBLIC_KEY”); StackMob.getStackMob().getSession().getLogger().setLogging(true); snapStackApplication = (SnapStackApplication) getApplication(); GPSTracker gps = new GPSTracker(this); if(!gps.canGetLocation()){ gps.showSettingsAlert(); } // Find our buttons sign_up = (Button) findViewById(R.id.signup_button); sign_in = (Button) findViewById(R.id.signin_button);
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// Set an OnClickListener for the sign_up button sign_up.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Intent intent = new Intent( MainActivity.this, SignUpActivity.class); startActivity(intent); } }); // Set an OnClickListener for the sign_in button sign_in.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Intent intent = new Intent( MainActivity.this, SignInActivity.class); startActivity(intent); } }); } @Override protected void onResume() { super.onResume(); if(StackMob.getStackMob().isLoggedIn()) { final ProgressDialog progressDialog = ProgressDialog.show( MainActivity.this, “Signing in”, “Signing back in”, true); User.getLoggedInUser(User.class, new StackMobQueryCallback() { @Override public void success(List list) { progressDialog.dismiss(); User user = list.get(0); snapStackApplication.setUser(user); Intent intent = new Intent( MainActivity.this, MasterActivity.class); startActivity(intent); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); Toast.makeText(MainActivity.this, “Couldn’t sign back in”, Toast.LENGTH_LONG).
show(); }
});
}
} }
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In MainActivity, we initialize the StackMob SDK. Copy your public key from the Dashboard and use it in the init method. The MainActivity simply presents two buttons that link to Sign Up and Sign In, respectively. At this point we’ve fully built out our sign up/sign in flows.
Sanity Check Build and run the app to check for errors. You’ll be greeted with MainActivity. Create an account and sign in.
Congrats! You’ve finished Part 2. In this part, we laid out the skeleton for our app; we setup the sign up and sign in flows and added forgot password functionality to our app. In Part 3, we’ll focus on the foundation of our app, MasterActivity.
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SnapStack Android Bootcamp
Part 3 What we’ll cover In this chapter we’ll add MasterActivity, the core of our app. It consists of a pull-to-refresh list view layered over a map view, and will serve as the main view in the app. We’ll also add a Profile view. Finally, we’ll build the feature to allow users to take and upload Snaps.
Adding DetailViewActivity Add an Activity called DetailViewActivity. This activity will serve as host to an individual Snap object. We’ll add more code to it in the next tutorial; for now, keep it as an empty view: package com.stackmob.snapstack; import android.app.Activity; public class DetailViewActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_detail); }
}
SnapAdapter We’ll display our Snaps in list views. To help with that, we’ll create a reusable ListAdapter as a helper class. Create a file named SnapAdapter, and add the following code: package com.stackmob.snapstack; import java.util.List; import import import import import import import
android.content.Context; android.graphics.Bitmap; android.graphics.BitmapFactory; android.view.LayoutInflater; android.view.View; android.view.ViewGroup; android.widget.ArrayAdapter;
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import android.widget.ImageView; import android.widget.TextView; import com.nostra13.universalimageloader.core.DisplayImageOptions; import com.nostra13.universalimageloader.core.ImageLoader; public class SnapAdapter extends ArrayAdapter {
private Context context; private List objects; private DisplayImageOptions options; protected ImageLoader imageLoader = ImageLoader.getInstance();
public SnapAdapter(Context context, List objects) { super(context, R.layout.listview_snap_item, objects);
this.objects = objects; this.context = context;
options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.placeholder) .showImageForEmptyUri(R.drawable.placeholder) .showImageOnFail(R.drawable.placeholder).cacheInMemory() .cacheOnDisc().bitmapConfig(Bitmap.Config.RGB_565).build(); } @Override public View getView(int position, View convertView, ViewGroup parent) { View view = convertView; if (view == null) { LayoutInflater inflater = (LayoutInflater) context .getSystemService(Context.LAYOUT_INFLATER_SERVICE); view = inflater.inflate(R.layout.listview_snap_item, null); } if (objects != null) { Snap snap = objects.get(position); ImageView snap_item_profile_image = (ImageView) view .findViewById(R.id.snap_item_profile_image); if (snap.getCreator().getPhoto() != null) { imageLoader.displayImage(snap.getCreator().getPhoto().getS3Url(), snap_item_profile_image, options); } else { Bitmap bitmap = BitmapFactory.decodeResource( context.getResources(), R.drawable.default_avatar); snap_item_profile_image.setImageBitmap(bitmap); } TextView user_name = (TextView) view .findViewById(R.id.snap_item_username); user_name.setText(snap.getCreator().getUsername()); ImageView snap_item_image = (ImageView) view .findViewById(R.id.snap_item_image); imageLoader.displayImage(snap.getPhoto() .getS3Url(), snap_item_image, options); } return view; } }
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Adding a Profile Create an Activity named ProfileActivity.java, with the following code: package com.stackmob.snapstack; import java.util.ArrayList; import java.util.List; import import import import import import import import import import import import import import import import import import import
android.app.Activity; android.content.Intent; android.graphics.Bitmap; android.graphics.BitmapFactory; android.os.Bundle; android.os.Handler; android.view.Menu; android.view.MenuInflater; android.view.MenuItem; android.view.View; android.view.animation.AlphaAnimation; android.view.animation.Animation; android.view.animation.DecelerateInterpolator; android.widget.AdapterView; android.widget.AdapterView.OnItemClickListener; android.widget.ImageView; android.widget.ListView; android.widget.TextView; android.widget.Toast;
import import import import import import import import import import
com.handmark.pulltorefresh.library.PullToRefreshBase; com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener; com.handmark.pulltorefresh.library.PullToRefreshListView; com.nostra13.universalimageloader.core.DisplayImageOptions; com.nostra13.universalimageloader.core.ImageLoader; com.stackmob.sdk.api.StackMobOptions; com.stackmob.sdk.api.StackMobQuery; com.stackmob.sdk.callback.StackMobNoopCallback; com.stackmob.sdk.callback.StackMobQueryCallback; com.stackmob.sdk.exception.StackMobException;
public class ProfileActivity extends Activity { SnapStackApplication snapStackApplication; private PullToRefreshListView pull_refresh_list; private List snaps = new ArrayList(); private Handler handler = new Handler(); private SnapAdapter adapter; private User user; private TextView profile_username; private ImageView profile_photo_imageview; private DisplayImageOptions options; protected ImageLoader imageLoader = ImageLoader.getInstance(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_profile); options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.default_avatar) .showImageForEmptyUri(R.drawable.default_avatar) .showImageOnFail(R.drawable.default_avatar) .cacheInMemory() .cacheOnDisc()
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.bitmapConfig(Bitmap.Config.RGB_565) .build(); snapStackApplication = (SnapStackApplication) getApplication(); user = snapStackApplication.getUser(); profile_photo_imageview = (ImageView) findViewById(R.id.profile_photo_imageview); if (user.getPhoto() != null) { imageLoader.displayImage(user.getPhoto().getS3Url(), profile_photo_imageview, options); } else { Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_
avatar);
}
profile_photo_imageview.setImageBitmap(bitmap);
profile_photo_imageview.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(ProfileActivity.this, ChoosePhotoActivity.class); intent.putExtra(“calling_activity”, 666); startActivityForResult(intent, 0); } }); profile_username = (TextView) findViewById(R.id.profile_username); profile_username.setText(user.getUsername()); pull_refresh_list = (PullToRefreshListView) findViewById(R.id.pull_refresh_list); pull_refresh_list.setOnRefreshListener(new OnRefreshListener() { @Override public void onRefresh(PullToRefreshBase refreshView) { loadObjects(); } }); pull_refresh_list.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View view, int position, long id){ Snap snap = snaps.get(position - 1); Intent intent = new Intent( ProfileActivity.this, DetailViewActivity.class); snapStackApplication.setSnap(snap);
});
}
startActivity(intent);
loadObjects(); } private class ListUpdater implements Runnable{ public ListUpdater(){ }
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show();
public void run(){ if (snaps.size() == 0) { Toast.makeText(ProfileActivity.this, “No Snaps found”, Toast.LENGTH_LONG).
}
} adapter = new SnapAdapter(ProfileActivity.this, snaps); pull_refresh_list.onRefreshComplete(); pull_refresh_list.setAdapter(adapter); Animation fadeIn = new AlphaAnimation(0, 1); fadeIn.setInterpolator(new DecelerateInterpolator()); //add this fadeIn.setDuration(1000); pull_refresh_list.setAnimation(fadeIn);
} @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.signout_menu, menu); }
return true;
@Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.signOut: SnapStackApplication snapStackApplication = (SnapStackApplication) this. getApplication(); snapStackApplication.getUser().logout(new StackMobNoopCallback()); Intent myIntent = new Intent(this, MainActivity.class); myIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(myIntent); return true; default: return super.onOptionsItemSelected(item); } } private void loadObjects() { StackMobQuery query = new StackMobQuery(); query.fieldIsOrderedBy(“createddate”, StackMobQuery.Ordering.DESCENDING); query.fieldIsEqualTo(“creator”, user.getUsername()); Snap.query(Snap.class, query, StackMobOptions.depthOf(1), new StackMobQueryCallback() { @Override public void success(List result) { snaps = result; handler.post(new ListUpdater()); } @Override public void failure(StackMobException e) { handler.post(new ListUpdater());
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} }); } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (resultCode == Activity.RESULT_OK) { imageLoader.clearDiscCache(); imageLoader.clearMemoryCache(); user = snapStackApplication.getUser(); imageLoader.displayImage(user.getPhoto().getS3Url(), profile_photo_imageview, options); } } }
The profile displays a user’s picture and username, as well as a list view of their Snaps. In onCreateOptionsMenu, we’ve added a sign out menu option to fully complete the flow for users. When onOptionsItemSelected is called, we sign the user out and bring them back to MainActivity. The loadObjects method queries for Snaps created by the user. We feed the objects to our SnapAdapter, which we pair with our list view.
Adding SharePhotoActivity One of the central features of the app is the share photo feature, where users take a photo and pair it with their location to create a Snap. We’ll walkthrough building that feature. Create an Activity called SharePhotoActivity, with the following code: package com.stackmob.snapstack; import import import import
java.io.ByteArrayOutputStream; java.io.File; java.util.ArrayList; java.util.List;
import import import import import import import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder; android.content.ActivityNotFoundException; android.content.ComponentName; android.content.Context; android.content.DialogInterface; android.content.Intent; android.content.pm.ResolveInfo; android.graphics.Bitmap; android.graphics.BitmapFactory; android.graphics.drawable.BitmapDrawable; android.net.Uri; android.os.Bundle; android.os.Environment; android.provider.MediaStore;
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import import import import import
android.view.View; android.widget.ArrayAdapter; android.widget.Button; android.widget.ImageView; android.widget.Toast;
import com.stackmob.sdk.api.StackMobFile; import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; public class SharePhotoActivity extends Activity {
SnapStackApplication snapStackApplication; private Uri imageCaptureUri; private ImageView share_photo_imageview; private Button share_photo_button; private ProgressDialog progressDialog;
private static final int PICK_FROM_CAMERA = 1; private static final int CROP_FROM_CAMERA = 2; private static final int PICK_FROM_FILE = 3;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_share_photo);
snapStackApplication = (SnapStackApplication) getApplication();
final String[] items = new String[] { “Take from camera”, “Select from gallery” }; ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.select_dialog_item, items); AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Select Image”); builder.setAdapter(adapter, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int item) { // pick from // camera if (item == 0) { Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); imageCaptureUri = Uri.fromFile(new File(Environment .getExternalStorageDirectory(), “tmp_avatar_” + String.valueOf(System.currentTimeMillis()) + “.jpg”)); intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageCaptureUri); try {
intent.putExtra(“return-data”, true);
startActivityForResult(intent, PICK_FROM_CAMERA); } catch (ActivityNotFoundException e) { e.printStackTrace(); } } else { // pick from file Intent intent = new Intent();
intent.setType(“image/*”); intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, “Complete action using”), PICK_FROM_FILE); }
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} }); final AlertDialog dialog = builder.create(); dialog.show(); share_photo_button = (Button) findViewById(R.id.share_photo_button); share_photo_button.setEnabled(false); share_photo_imageview = (ImageView) findViewById(R.id.share_photo_imageview); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.placeholder); share_photo_imageview.setImageBitmap(bitmap); share_photo_imageview.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { dialog.show(); } }); share_photo_button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { progressDialog = ProgressDialog.show( SharePhotoActivity.this, “Saving...”, “Saving your snap”, true); Bitmap bitmap = ((BitmapDrawable) share_photo_imageview .getDrawable()).getBitmap(); ByteArrayOutputStream stream = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream); byte[] image = stream.toByteArray(); Snap snap = snapStackApplication.getSnap(); snap.setPhoto(new StackMobFile(“image/jpeg”, “profile_picture.jpg”, image)); snap.save(new StackMobModelCallback() { @Override public void success() { progressDialog.dismiss(); threadAgnosticDialog(SharePhotoActivity.this, “Your photo was shared to SnapStack!”); setResult(RESULT_OK, null); finish(); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); threadAgnosticDialog(SharePhotoActivity.this, “There was an error saving your photo.”); } }); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode != RESULT_OK) return;
switch (requestCode) {
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case PICK_FROM_CAMERA: doCrop(); break; case PICK_FROM_FILE: imageCaptureUri = data.getData(); doCrop(); break; case CROP_FROM_CAMERA: Bundle extras = data.getExtras(); if (extras != null) { Bitmap photo = extras.getParcelable(“data”); share_photo_imageview.setImageBitmap(photo); share_photo_button.setEnabled(true); }
File f = new File(imageCaptureUri.getPath());
if (f.exists()) f.delete(); break; } } private void doCrop() { final ArrayList cropOptions = new ArrayList();
Intent intent = new Intent(“com.android.camera.action.CROP”); intent.setType(“image/*”);
List list = getPackageManager().queryIntentActivities( intent, 0);
int size = list.size();
if (size == 0) { Toast.makeText(this, “Can not find image crop app”, Toast.LENGTH_SHORT).show(); return; } else { intent.setData(imageCaptureUri);
intent.putExtra(“outputX”, 200); intent.putExtra(“outputY”, 200); intent.putExtra(“aspectX”, 1); intent.putExtra(“aspectY”, 1); intent.putExtra(“scale”, true); intent.putExtra(“return-data”, true);
if (size == 1) { Intent i = new Intent(intent); ResolveInfo res = list.get(0); i.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name)); startActivityForResult(i, CROP_FROM_CAMERA); } else {
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for (ResolveInfo res : list) { final CropOption co = new CropOption(); co.title = getPackageManager().getApplicationLabel( res.activityInfo.applicationInfo); co.icon = getPackageManager().getApplicationIcon( res.activityInfo.applicationInfo); co.appIntent = new Intent(intent); co.appIntent .setComponent(new ComponentName( res.activityInfo.packageName, res.activityInfo.name)); cropOptions.add(co); } CropOptionAdapter adapter = new CropOptionAdapter( getApplicationContext(), cropOptions); AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle(“Choose Crop App”); builder.setAdapter(adapter, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int item) { startActivityForResult( cropOptions.get(item). appIntent, CROP_FROM_CAMERA); } }); builder.setOnCancelListener(new DialogInterface.OnCancelListener() { @Override public void onCancel(DialogInterface dialog) { if (imageCaptureUri != null) { getContentResolver().delete(imageCaptureUri, null, null); imageCaptureUri = null; } } }); AlertDialog alert = builder.create(); alert.show(); } } } private void threadAgnosticDialog(final Context ctx, final String txt) { runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder(ctx); builder.setTitle(“Share Photo”); builder.setCancelable(true); builder.setMessage(txt); AlertDialog dialog = builder.create(); dialog.show(); } }); } }
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This activity works much like the ChoosePhotoActivity; we call the same Camera intent and use the same doCrop method to crop our images. Once we have a photo, we attach it to the Snap object stored in SnapStackApplication, and call save. If the save is successful, we call finish on SharePhotoActivity.
The MasterActivity In the last part of the tutorial, we left MasterActivity blank. Add the following code to MasterActivity: package com.stackmob.snapstack; import java.util.ArrayList; import java.util.List; import import import import import import import import import import import import import import import import import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.AlertDialog.Builder; android.app.Dialog; android.content.Context; android.content.DialogInterface; android.content.Intent; android.graphics.Bitmap; android.location.Location; android.os.Bundle; android.os.Handler; android.view.LayoutInflater; android.view.View; android.view.animation.AccelerateInterpolator; android.view.animation.AlphaAnimation; android.view.animation.Animation; android.view.animation.DecelerateInterpolator; android.widget.AdapterView; android.widget.AdapterView.OnItemClickListener; android.widget.CompoundButton; android.widget.ImageButton; android.widget.ImageView; android.widget.LinearLayout; android.widget.ListView; android.widget.Toast; android.widget.ToggleButton;
import import import import import import import import import import import import import import import import import import import import
com.google.android.gms.common.ConnectionResult; com.google.android.gms.common.GooglePlayServicesUtil; com.google.android.gms.maps.CameraUpdateFactory; com.google.android.gms.maps.GoogleMap; com.google.android.gms.maps.GoogleMap.OnMarkerClickListener; com.google.android.gms.maps.MapFragment; com.google.android.gms.maps.model.LatLng; com.google.android.gms.maps.model.LatLngBounds; com.google.android.gms.maps.model.Marker; com.google.android.gms.maps.model.MarkerOptions; com.handmark.pulltorefresh.library.PullToRefreshBase; com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener; com.handmark.pulltorefresh.library.PullToRefreshListView; com.nostra13.universalimageloader.core.DisplayImageOptions; com.nostra13.universalimageloader.core.ImageLoader; com.stackmob.sdk.api.StackMobGeoPoint; com.stackmob.sdk.api.StackMobOptions; com.stackmob.sdk.api.StackMobQuery; com.stackmob.sdk.callback.StackMobQueryCallback; com.stackmob.sdk.exception.StackMobException;
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public class MasterActivity extends Activity { private SnapStackApplication snapStackApplication; private ImageButton profile_button; private ImageButton camera_button; private GoogleMap map; private LinearLayout transparent_cover; private PullToRefreshListView pull_refresh_list; private ToggleButton toggle_button; private List snaps = new ArrayList(); private Handler handler = new Handler(); private SnapAdapter adapter; private GPSTracker gps; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_master); gps = new GPSTracker(this); snapStackApplication = (SnapStackApplication) getApplication(); // Getting Google Play availability status int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext()); // Showing status if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available int requestCode = 10; Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode); dialog.show(); } profile_button = (ImageButton) findViewById(R.id.profile_button); profile_button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent( MasterActivity.this, ProfileActivity.class); startActivity(intent); } });
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)) .getMap(); map.setMyLocationEnabled(true); map.getUiSettings().setAllGesturesEnabled(false); camera_button = (ImageButton) findViewById(R.id.camera_button); camera_button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (gps.getLocation() == null) { Builder builder = new AlertDialog.Builder(MasterActivity.this); builder.setTitle(“Oh snap!”); builder.setCancelable(true); builder.setMessage(“Couldn’t get your location.”);
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AlertDialog dialog = builder.create(); dialog.show(); return; } Location location = gps.getLocation(); StackMobGeoPoint point = new StackMobGeoPoint(location.getLongitude(), location.getLatitude()); User user = snapStackApplication.getUser(); Snap snap = new Snap(user, point); snapStackApplication.setSnap(snap); Intent intent = new Intent( MasterActivity.this, SharePhotoActivity.class); startActivityForResult(intent, 0); } }); transparent_cover = (LinearLayout) findViewById(R.id.transparent_cover); pull_refresh_list = (PullToRefreshListView) findViewById(R.id.pull_refresh_list); adapter = new SnapAdapter(MasterActivity.this, snaps); pull_refresh_list.setAdapter(adapter); pull_refresh_list.setRefreshing(true); pull_refresh_list.setOnRefreshListener(new OnRefreshListener() { @Override public void onRefresh(PullToRefreshBase refreshView) { loadObjects(); } }); pull_refresh_list.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View view, int position, long id){ Snap snap = snaps.get(position - 1); Intent intent = new Intent( MasterActivity.this, DetailViewActivity.class); snapStackApplication.setSnap(snap);
});
}
startActivityForResult(intent, 0);
toggle_button = (ToggleButton) findViewById(R.id.toggle_button); toggle_button.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { // Save the state here if (isChecked) { Animation fadeOut = new AlphaAnimation(1, 0); fadeOut.setInterpolator(new AccelerateInterpolator()); //and this fadeOut.setDuration(500); transparent_cover.setAnimation(fadeOut); pull_refresh_list.setAnimation(fadeOut); transparent_cover.setVisibility(View.GONE);
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pull_refresh_list.setVisibility(View.GONE); map.getUiSettings().setAllGesturesEnabled(true); } else { transparent_cover.setVisibility(View.VISIBLE); pull_refresh_list.setVisibility(View.VISIBLE);
});
} }
Animation fadeIn = new AlphaAnimation(0, 1); fadeIn.setInterpolator(new DecelerateInterpolator()); fadeIn.setDuration(500); transparent_cover.setAnimation(fadeIn); pull_refresh_list.setAnimation(fadeIn); map.getUiSettings().setAllGesturesEnabled(false);
map.setOnMarkerClickListener(new OnMarkerClickListener() { @Override public boolean onMarkerClick(final Marker marker) { AlertDialog.Builder builder = new AlertDialog.Builder(MasterActivity. this); LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); View v = inflater.inflate(R.layout.activity_photo, null); builder.setView(v); int i = Integer.parseInt(marker.getSnippet()); Snap snap = snaps.get(i); ImageView imageView = (ImageView) v.findViewById(R.id.photo_image); DisplayImageOptions options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.placeholder) .showImageForEmptyUri(R.drawable.placeholder) .showImageOnFail(R.drawable.placeholder) .cacheInMemory() .cacheOnDisc() .bitmapConfig(Bitmap.Config.RGB_565) .build(); ImageLoader imageLoader = ImageLoader.getInstance(); imageLoader.displayImage(snap.getPhoto().getS3Url(), imageView, options); imageView.setAdjustViewBounds(true); imageView.setMaxHeight(150); imageView.setMaxWidth(150); imageView.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { int i = Integer.parseInt(marker.getSnippet()); Snap snap = snaps.get(i); Intent intent = new Intent( MasterActivity.this, DetailViewActivity.class); snapStackApplication.setSnap(snap);
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});
startActivity(intent);
}
builder.setPositiveButton(“Show Details”, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int id) { int i = Integer.parseInt(marker.getSnippet()); Snap snap = snaps.get(i); Intent intent = new Intent( MasterActivity.this, DetailViewActivity.class); }
snapStackApplication.setSnap(snap); startActivity(intent);
}); builder.setNegativeButton(“Close”, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); } }); Dialog dialog = builder.create(); dialog.show(); return true; } }); loadObjects(); } private void setMarkers () { if (snaps == null || snaps.size() == 0) return; LatLngBounds.Builder builder = new LatLngBounds.Builder(); for (int i = 0; i < snaps.size(); i++) { Snap snap = snaps.get(i); LatLng point = new LatLng(snap.getLocation().getLatitude(), snap. getLocation().getLongitude()); builder.include(point); map.addMarker(new MarkerOptions().position(point) .snippet(“”+i)); } if (gps.canGetLocation) { LatLng location = new LatLng(gps.latitude, gps.longitude); builder.include(location); } LatLngBounds bounds = builder.build(); map.animateCamera(CameraUpdateFactory.newLatLngBounds(bounds, 30)); }
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private class ListUpdater implements Runnable{ public ListUpdater(){ }
public void run(){ if (snaps.size() == 0) { Toast.makeText(MasterActivity.this, “Couldn’t find any Snaps nearby”, Toast. LENGTH_LONG).show(); } adapter = new SnapAdapter(MasterActivity.this, snaps); pull_refresh_list.onRefreshComplete(); pull_refresh_list.setAdapter(adapter); setMarkers(); Animation fadeIn = new AlphaAnimation(0, 1); fadeIn.setInterpolator(new DecelerateInterpolator()); //add this fadeIn.setDuration(1000); pull_refresh_list.setAnimation(fadeIn); } } private void loadObjects() { Location location = gps.getLocation(); if (location == null) { pull_refresh_list.onRefreshComplete(); Toast.makeText(this, “Couldn’t get your location”, Toast.LENGTH_LONG).show(); return; } LatLng currentLocation = new LatLng(location.getLatitude(), location.getLongitude()); // Move the camera instantly to the current location with a zoom of 15. map.animateCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, 15)); StackMobGeoPoint point = new StackMobGeoPoint(location.getLongitude(), location. getLatitude()); StackMobQuery query = new StackMobQuery(); query.fieldIsNear(“location”, point); query.fieldIsOrderedBy(“createddate”, StackMobQuery.Ordering.DESCENDING); query.isInRange(0, 50); Snap.query(Snap.class, query, StackMobOptions.depthOf(1), new StackMobQueryCallback() { @Override public void success(List result) { snaps = result; handler.post(new ListUpdater()); } @Override public void failure(StackMobException e) { handler.post(new ListUpdater()); } });
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} @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (resultCode == Activity.RESULT_OK) { loadObjects(); } } }
MasterActivity handles a lot at once. We have a map fragment, using the Google Maps Android v2 API. Layered on top of it is a pull-to-refresh list view for Snap objects. Beneath the list view is a toggle button to switch between the map and the list view; each time, the list view is faded out or in with an animation. The loadObjects method grabs the users location from the map, and queries for Snaps nearby. If a query is successful, the list view is refreshed using the run method from our private ListUpdater. The list view uses SnapAdapter to build its list items. Also in the run method, we update the map fragment, using the setMarkers. This method plots the Snaps as annotations using their locations, and focuses the map camera to fit them all. The map uses an OnMarkerClickListener to build a custom dialog window for the annotations; when an annotation is selected, the image associated with the Snap is shown. Finally the MasterActivity has links to the ProfileActivity and SharePhotoActivity we just built.
Congrats! You’ve finished Part 3. We added the ability to take and upload Snap. We also added a Profile with sign out. Finally, we added the biggest piece of our app, MasterActivity. In Part 4, we’ll wrap up development on SnapStack.
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SnapStack Android Bootcamp
Part 4 What we’ll cover In this chapter, we’ll focus on the detail view and comment view to our app. We’ll also add the ability to delete Snaps. Finally, we’ll finish with the ability to add comments to Snaps.
PhotoViewActivity Add an Activity named PhotoViewActivity: package com.stackmob.snapstack; import import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder; android.graphics.Bitmap; android.os.Bundle; android.view.Menu; android.view.MenuInflater; android.view.MenuItem; android.widget.ImageView;
import import import import
com.nostra13.universalimageloader.core.DisplayImageOptions; com.nostra13.universalimageloader.core.ImageLoader; com.stackmob.sdk.callback.StackMobModelCallback; com.stackmob.sdk.exception.StackMobException;
public class PhotoViewActivity extends Activity { private Snap snap; SnapStackApplication snapStackApplication; DisplayImageOptions options; protected ImageLoader imageLoader = ImageLoader.getInstance(); private ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_photo); options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.placeholder) .showImageForEmptyUri(R.drawable.placeholder) .showImageOnFail(R.drawable.placeholder) .cacheInMemory() .cacheOnDisc() .bitmapConfig(Bitmap.Config.RGB_565) .build();
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snapStackApplication = (SnapStackApplication) getApplication(); snap = snapStackApplication.getSnap();
ImageView imageView = (ImageView) findViewById(R.id.photo_image); imageLoader.displayImage(snap.getPhoto().getS3Url(), imageView, options);
} @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.delete_menu, menu); String username = snap.getCreator().getUsername(); User user = snapStackApplication.getUser(); if (username.equals(user.getUsername())) { return true; } }
return false;
@Override public boolean onOptionsItemSelected(MenuItem item) { progressDialog = ProgressDialog.show( PhotoViewActivity.this, “Deleting...”, “Deleting your snap”, true); snap.destroy(new StackMobModelCallback() { @Override public void success() { // the call succeeded progressDialog.dismiss(); setResult(RESULT_OK, null); finish(); } @Override public void failure(StackMobException e) { // the call failed progressDialog.dismiss(); runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog. Builder(PhotoViewActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“Couldn’t delete snap”); AlertDialog dialog = builder.create(); dialog.show(); } }); } });
}
}
return true;
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PhotoViewActivity is very basic; it displays the photo from the Snap selected. The onCreateOptionsMenu presents the option to delete the Snap, if it was created by the user. When onOptionsItemSelected is called, we use the destroy method on the Snap object. If the delete is successful, we call finish on the activity.
ShareCommentActivity In SnapStack, users can add comments to Snaps. Add an Activity named ShareCommentActivity: package com.stackmob.snapstack; import import import import import import import import import
android.app.Activity; android.app.AlertDialog; android.app.AlertDialog.Builder; android.app.ProgressDialog; android.content.Context; android.os.Bundle; android.view.View; android.widget.Button; android.widget.EditText;
import com.stackmob.sdk.callback.StackMobModelCallback; import com.stackmob.sdk.exception.StackMobException; public class ShareCommentActivity extends Activity { private SnapStackApplication snapStackApplication; private EditText comment_edittext; private Button share_comment_button; private ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_share_comment); snapStackApplication = (SnapStackApplication) getApplication(); comment_edittext = (EditText) findViewById(R.id.comment_edittext); share_comment_button = (Button) findViewById(R.id.share_comment_button); share_comment_button.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View arg0) { String commentText = comment_edittext.getText().toString(); if (commentText.trim().length() != 0){ progressDialog = ProgressDialog.show( ShareCommentActivity.this, “Saving”, “Saving comment”, true); User user = snapStackApplication.getUser(); final Snap snap = snapStackApplication.getSnap(); Comment comment = new Comment(user, commentText, snap);
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comment.save(new StackMobModelCallback() { @Override public void success() { // the call succeeded progressDialog.dismiss(); setResult(RESULT_OK, null); finish(); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); // the call failed threadAgnosticDialog(ShareCommentActivity.this, “There was an error saving your comment.”); } }); } } }); } private void threadAgnosticDialog(final Context ctx, final String txt) { runOnUiThread(new Runnable() { @Override public void run() { Builder builder = new AlertDialog.Builder(ctx); builder.setCancelable(true); builder.setMessage(txt); AlertDialog dialog = builder.create(); dialog.show(); } }); } }
This activity presents a simple EditText for users to type comments. Once the share button is clicked, we create a Comment object, complete with the User who created it, the text of the comment and the associated Snap. After we call save, if it’s successful, we finish the activity.
CommentViewActivity Now that we’ve built the feature to add comments, we’ll make an Activity to display them. Add an Activity named CommentViewActivity: package com.stackmob.snapstack; import java.util.ArrayList; import java.util.List; import import import import
android.app.Activity; android.app.AlertDialog; android.app.ProgressDialog; android.app.AlertDialog.Builder;
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import import import import import import import import import import import import
android.content.Context; android.graphics.Bitmap; android.graphics.BitmapFactory; android.os.Bundle; android.os.Handler; android.view.LayoutInflater; android.view.View; android.view.ViewGroup; android.widget.ArrayAdapter; android.widget.ImageView; android.widget.ListView; android.widget.TextView;
import import import import import import
com.nostra13.universalimageloader.core.DisplayImageOptions; com.nostra13.universalimageloader.core.ImageLoader; com.stackmob.sdk.api.StackMobOptions; com.stackmob.sdk.api.StackMobQuery; com.stackmob.sdk.callback.StackMobQueryCallback; com.stackmob.sdk.exception.StackMobException;
public class CommentViewActivity extends Activity {
List comments; ListView listView; private SnapStackApplication snapStackApplication; private Handler handler = new Handler(); CommentAdapter adapter;
DisplayImageOptions options; protected ImageLoader imageLoader = ImageLoader.getInstance(); private ProgressDialog progressDialog;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_comment); options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.placeholder) .showImageForEmptyUri(R.drawable.placeholder) .showImageOnFail(R.drawable.placeholder).cacheInMemory() .cacheOnDisc().bitmapConfig(Bitmap.Config.RGB_565).build();
listView = (ListView) findViewById(R.id.comment_listview);
comments = new ArrayList();
snapStackApplication = (SnapStackApplication) getApplication();
adapter = new CommentAdapter(CommentViewActivity.this, comments); listView.setAdapter(adapter); loadComments(); }
public void loadComments() {
progressDialog = ProgressDialog.show(CommentViewActivity.this, “Loading...”, “Loading comments”, true);
Snap snap = snapStackApplication.getSnap(); StackMobQuery query = new StackMobQuery(); query.fieldIsEqualTo(“snap”, snap.getID());
Comment.query(Comment.class, query, StackMobOptions.depthOf(1), new StackMobQueryCallback() { @Override public void success(List result) {
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progressDialog.dismiss(); comments = result; handler.post(new ListUpdater()); } @Override public void failure(StackMobException e) { progressDialog.dismiss(); handler.post(new ListUpdater()); Builder builder = new AlertDialog.Builder( CommentViewActivity.this); builder.setTitle(“Uh oh...”); builder.setCancelable(true); builder.setMessage(“There was an error loading comments.”); AlertDialog dialog = builder.create(); dialog.show(); } }); }
private class ListUpdater implements Runnable {
public ListUpdater() {
} public void run() { adapter = new CommentAdapter(CommentViewActivity.this, comments); listView.setAdapter(adapter); } }
private class CommentAdapter extends ArrayAdapter {
private List objects;
public CommentAdapter(Context context, List objects) { super(context, R.layout.listview_comment_item, objects); this.objects = objects; } @Override public View getView(int position, View convertView, ViewGroup parent) { View view = convertView; if (view == null) { LayoutInflater inflater = (LayoutInflater) CommentViewActivity.this .getSystemService(Context.LAYOUT_INFLATER_SERVICE); view = inflater.inflate(R.layout.listview_comment_item, null); } if (objects != null) { Comment comment = objects.get(position); TextView user_name = (TextView) view .findViewById(R.id.comment_username); user_name.setText(comment.getCreator().getUsername()); ImageView comment_item_profile_image = (ImageView) view .findViewById(R.id.comment_item_profile_image);
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if (comment.getCreator().getPhoto() != null) {
imageLoader.displayImage(comment.getCreator().getPhoto() .getS3Url(), comment_item_profile_image, options); } else { Bitmap bitmap = BitmapFactory.decodeResource( getResources(), R.drawable.default_avatar); comment_item_profile_image.setImageBitmap(bitmap); }
TextView text = (TextView) view.findViewById(R.id.comment_text); text.setText(comment.getText());
} return view; } } }
In CommentViewActivity we’ve built a ListAdapter similar to SnapAdapter. In the OnCreate method, we call loadComments, which queries for any Comments associated with the Snap.
DetailViewActivity Add an Activity named DetailViewActivity, which simply ties all of previous Activities together: package com.stackmob.snapstack; import import import import import import import import import import import import import import import import
android.app.Activity; android.content.Intent; android.graphics.Bitmap; android.graphics.BitmapFactory; android.os.Bundle; android.view.Menu; android.view.MenuInflater; android.view.MenuItem; android.view.View; android.view.View.OnClickListener; android.view.animation.AlphaAnimation; android.view.animation.Animation; android.view.animation.DecelerateInterpolator; android.widget.Button; android.widget.ImageView; android.widget.TextView;
import import import import import
com.nostra13.universalimageloader.core.DisplayImageOptions; com.nostra13.universalimageloader.core.ImageLoader; com.stackmob.sdk.api.StackMobQuery; com.stackmob.sdk.callback.StackMobCountCallback; com.stackmob.sdk.exception.StackMobException;
public class DetailViewActivity extends Activity {
private Snap snap; SnapStackApplication snapStackApplication;
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private Button commentsButton;
DisplayImageOptions options; protected ImageLoader imageLoader = ImageLoader.getInstance();
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_detail); options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.placeholder) .showImageForEmptyUri(R.drawable.placeholder) .showImageOnFail(R.drawable.placeholder).cacheInMemory() .cacheOnDisc().bitmapConfig(Bitmap.Config.RGB_565).build();
snapStackApplication = (SnapStackApplication) getApplication();
snap = snapStackApplication.getSnap();
TextView user_name = (TextView) findViewById(R.id.detail_username); user_name.setText(snap.getCreator().getUsername());
ImageView detail_profile_image = (ImageView) findViewById(R.id.detail_profile_image);
if (snap.getCreator().getPhoto() != null) {
imageLoader.displayImage(snap.getCreator().getPhoto().getS3Url(), detail_profile_image, options); } else { Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_avatar); detail_profile_image.setImageBitmap(bitmap); } ImageView imageView = (ImageView) findViewById(R.id.detail_image); imageLoader .displayImage(snap.getPhoto().getS3Url(), imageView, options); imageView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(DetailViewActivity.this, PhotoViewActivity.class); } });
startActivityForResult(intent, 0);
commentsButton = (Button) findViewById(R.id.detail_comments); commentsButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(DetailViewActivity.this, CommentViewActivity.class); startActivityForResult(intent, 0); } }); commentsButton.setVisibility(View.GONE); countComments(); } private void countComments(){
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Snap snap = snapStackApplication.getSnap(); StackMobQuery query = new StackMobQuery(); query.fieldIsEqualTo(“snap”, snap.getID()); Comment.count(Comment.class, query, new StackMobCountCallback(){ @Override public void success(long count) { // TODO Auto-generated method stub String commentLabel; if (count == 0) { return; } else if (count > 1) { commentLabel = “ Comments”; } else { commentLabel = “ Comment”; } final String label = “” + (int)count + commentLabel; runOnUiThread(new Runnable() { @Override public void run() { commentsButton.setText(label); commentsButton.setVisibility(View.VISIBLE); Animation fadeIn = new AlphaAnimation(0, 1); fadeIn.setInterpolator(new DecelerateInterpolator()); fadeIn.setDuration(500); commentsButton.setAnimation(fadeIn); } }); } @Override public void failure(StackMobException arg0) { // TODO Auto-generated method stub } }); } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (resultCode == Activity.RESULT_OK && requestCode == 0) { setResult(RESULT_OK, null); finish(); } if (resultCode == Activity.RESULT_OK && requestCode == 1) { setResult(RESULT_OK, null); countComments(); } } @Override
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public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.comment_menu, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { Intent intent = new Intent(DetailViewActivity.this, ShareCommentActivity.class);
startActivityForResult(intent, 1);
return true; } }
Build and run Build an run, and you have a complete app on your hands!
Congrats! After completing this part, our app is operating and fully functional. In Part 5, we’ll detail the steps to submit our finished app to the Google Play Store.
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SnapStack Android Bootcamp
Part 5 What we’ll cover In this chapter, we’ll talk about testing on our app, push to production and learn how to submit to the Play Store.
Testing your app Although we strive for our code to be perfect, usually it ends up far from it. It’s not a question of if your application has bugs, but when and how many. It’s very important to test your app as much as possible before releasing to the Google Play Store. Fortunately, there are a few resources available to help in this process.
Android emulator The Android Emulator comes packaged with the Android SDK, and allows for the developers to create many different virtual devices. Using the emulator, a developer can test against a large selection of Android API levels.
Ad-hoc distribution With Android, it’s very easy to build and distribute your app to potential testers. Simply export and APK file of the project, and you can install it on anyones phone. To export a project into an APK, right click the project and select export:
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Under Android, select “Export Android Application” and click next:
In the keystore selection screen, navigate to wherever your production keystore is located. If you don’t have a production keystore, you can create one. Enter your keystore password and click next.
Select your keystore key alias, enter your password and click next.
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Finally, choose a place to save your APK and click finish.
Developers can send out their APKs to groups of testers and have them install right from email. This makes ad-hoc distribution and coordination less painful.
Deploy to Production Now that you’ve finished building and testing your app, it’s ready to be released, right? Not so fast. Before we showcase our creation to the world, we need to setup our production environment. During the development process, everything about your app is in the development stage. This allows you to test and experiment. Once your app goes public, you’ll want to separate everything into two separate environments: Development and Production. This provides you the opportunity to test changes and improvements in your app without directly affecting live users. To accomplish this on StackMob, head to the deploy section of your dashboard. Check “Deploy API” and click Deploy. Enter a version number, and all of your schemas will be copied over into a Production environment.
Tip: If it’s your first time deploying to production, use the version number 1. Back in Eclipse, update where we instantiate StackMob in MainActivity; add your Production keys and change your version number to 1. StackMobAndroid.init(getApplicationContext(), 1, “YOUR_PROD_PUBLIC_KEY”);
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Preparing for release To submit apps to the Google Play store, you’ll need to be registered for a Google Play publisher account. Check out this tutorial on how to register to be a Google Play publisher. Once you’ve registered, you’ll be provided with a developer console to view the status of your apps. Google provides an excellent walkthrough of the Google Play developer console. Finally, the time comes to submit to the Google Play store. Make sure you follow the checklist for submitting to the Play store, a detailed tutorial provided by Google for developers in preparation for release.
Congrats! You’ve successfully completed our Android bootcamp. We went through the different stages of development a pieced together a complete app. Using StackMob allowed us to rapidly build in the features for this app. Let’s recap the benefits brought by utilizing the StackMob platform and our Android SDK: • User Authentication • Access Control Lists (ACL) • CRUD API • S3 Integration • GeoPoints • Development and Production Environments Imagine if you had to create that backend entirely by yourself! Through this series, you’ve seen the power of the StackMob platform, as well as its flexibility. The possibilities are endless for developers who utilize StackMob with their apps and services. In the final chapter, we’ll finish out our SnapStack series with a final post about monitoring the performance of your app. If you’re new to StackMob, it’s completely free to get started. Sign up today!
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