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Android: How can I get the current foreground activity (from a service)?

android android-activity service

Question

Is there a native android way to get a reference to the currently running Activity from a service?

I have a service running on the background, and I would like to update my current Activity when an event occurs (in the service). Is there a easy way to do that (like the one I suggested above)?

1
171
10/6/2010 2:51:06 PM

Accepted Answer

Is there a native android way to get a reference to the currently running Activity from a service?

You may not own the "currently running Activity".

I have a service running on the background, and I would like to update my current Activity when an event occurs (in the service). Is there a easy way to do that (like the one I suggested above)?

  1. Send a broadcast Intent to the activity -- here is a sample project demonstrating this pattern
  2. Have the activity supply a PendingIntent (e.g., via createPendingResult()) that the service invokes
  3. Have the activity register a callback or listener object with the service via bindService(), and have the service call an event method on that callback/listener object
  4. Send an ordered broadcast Intent to the activity, with a low-priority BroadcastReceiver as backup (to raise a Notification if the activity is not on-screen) -- here is a blog post with more on this pattern
82
2/21/2014 12:31:14 PM

Here's a good way to do it using the activity manager. You basically get the runningTasks from the activity manager. It will always return the currently active task first. From there you can get the topActivity.

Example here

There's an easy way of getting a list of running tasks from the ActivityManager service. You can request a maximum number of tasks running on the phone, and by default, the currently active task is returned first.

Once you have that you can get a ComponentName object by requesting the topActivity from your list.

Here's an example.

    ActivityManager am = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE);
    List<ActivityManager.RunningTaskInfo> taskInfo = am.getRunningTasks(1);
    Log.d("topActivity", "CURRENT Activity ::" + taskInfo.get(0).topActivity.getClassName());
    ComponentName componentInfo = taskInfo.get(0).topActivity;
    componentInfo.getPackageName();

You will need the following permission on your manifest:

<uses-permission android:name="android.permission.GET_TASKS"/>
Nelson Ramirez

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