Preserving Navigation when Starting an Activity in Android

Part of designing a notification is preserving the user’s expected navigation experience. For a detailed discussion of this topic, see the Notifications API guide. There are two general situations:

Regular activity

You’re starting an Activity that’s part of the application’s normal workflow.

Special activity

The user only sees this Activity if it’s started from a notification. In a sense, the Activityextends the notification by providing information that would be hard to display in the notification itself.

Set Up a Regular Activity PendingIntent

To set up a PendingIntent that starts a direct entry Activity, follow these steps:

1. Define your application’s Activity hierarchy in the manifest. The final XML should look like this:

   <activity
       android:name=".MainActivity"
       android:label="@string/app_name" >
       <intent-filter>
           <action android:name="android.intent.action.MAIN" />
           <category android:name="android.intent.category.LAUNCHER" />
       </intent-filter>
   </activity>
   <activity
       android:name=".ResultActivity"
       android:parentActivityName=".MainActivity">
       <meta-data
           android:name="android.support.PARENT_ACTIVITY"
           android:value=".MainActivity"/>
   </activity>

2. Create a back stack based on the Intent that starts the Activity. For example:

   int id = 1;
   ...
   Intent resultIntent = new Intent(this, ResultActivity.class);
   TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
   // Adds the back stack
   stackBuilder.addParentStack(ResultActivity.class);
   // Adds the Intent to the top of the stack
   stackBuilder.addNextIntent(resultIntent);
   // Gets a PendingIntent containing the entire back stack
   PendingIntent resultPendingIntent =
           stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
   ...
   NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
   builder.setContentIntent(resultPendingIntent);
   NotificationManager mNotificationManager =
       (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
   mNotificationManager.notify(id, builder.build());

   Set Up a Special Activity PendingIntent

   ---

   A special Activity doesn’t need a back stack, so you don’t have to define its Activity hierarchy in the manifest, and you don’t have to calladdParentStack() to build a back stack. Instead, use the manifest to set up the Activity task options, and create the PendingIntent by callinggetActivity():

   1. In your manifest, add the following attributes to the <activity> element for the Activity:

      android:name="activityclass"

      The activity’s fully-qualified class name.

      android:taskAffinity=""

      Combined with the FLAG_ACTIVITY_NEW_TASK flag that you set in code, this ensures that this Activity doesn’t go into the application’s default task. Any existing tasks that have the application’s default affinity are not affected.

      android:excludeFromRecents="true"

      Excludes the new task from Recents, so that the user can’t accidentally navigate back to it.

      This snippet shows the element:

      <activity
          android:name=".ResultActivity"
      ...
          android:launchMode="singleTask"
          android:taskAffinity=""
          android:excludeFromRecents="true">
      </activity>
      ...

   2. Build and issue the notification:
      1. Create an Intent that starts the Activity.
      2. Set the Activity to start in a new, empty task by calling setFlags() with the flags FLAG_ACTIVITY_NEW_TASK and FLAG_ACTIVITY_CLEAR_TASK.
      3. Set any other options you need for the Intent.
      4. Create a PendingIntent from the Intent by calling getActivity(). You can then use this PendingIntent as the argument tosetContentIntent().

      The following code snippet demonstrates the process:

      // Instantiate a Builder object.
      NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
      // Creates an Intent for the Activity
      Intent notifyIntent =
              new Intent(new ComponentName(this, ResultActivity.class));
      // Sets the Activity to start in a new, empty task
      notifyIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
              Intent.FLAG_ACTIVITY_CLEAR_TASK);
      // Creates the PendingIntent
      PendingIntent notifyIntent =
              PendingIntent.getActivity(
              this,
              0,
              notifyIntent,
              PendingIntent.FLAG_UPDATE_CURRENT
      );
      
      // Puts the PendingIntent into the notification builder
      builder.setContentIntent(notifyIntent);
      // Notifications are issued by sending them to the
      // NotificationManager system service.
      NotificationManager mNotificationManager =
          (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
      // Builds an anonymous Notification object from the builder, and
      // passes it to the NotificationManager
      mNotificationManager.notify(id, builder.build());