Android: OnDestroy isn't called when I close the app from the recent apps button

Question

When we press this button

We see the apps which we didn't close, like this

But when we want to close an app from this screen (below image), the method onDestroy() isn't called, however the app is closed. I need to call onDestroy() when the app is closed in this way. How can I do this?

Answer 1

As specified in the Android documentation, it is not guaranteed that onDestroy() will be called when exiting your application.

"There are situations where the system will simply kill the activity's hosting process without calling this method"

https://developer.android.com/reference/android/app/Activity.html#onDestroy%28%29

Instead, you can create a service which will be notified when the Task your activities are running inside is destroyed.

Create the service class:

public class ClosingService extends Service {      @Nullable     @Override     public IBinder onBind(Intent intent) {         return null;     }      @Override     public void onTaskRemoved(Intent rootIntent) {         super.onTaskRemoved(rootIntent);          // Handle application closing         fireClosingNotification();          // Destroy the service         stopSelf();     } } 

Declare / register your service in the manifest (within the application tag, but outside any activity tags):

<service android:name=".services.ClosingService"              android:stopWithTask="false"/> 

Specifying stopWithTask="false" will cause the onTaskRemoved() method to be triggered in your service when the task is removed from the Process.

Here you can run your closing application logic, before calling stopSelf() to destroy the Service.

Answer 2

You should read some info about Activity lifecycle. There is one thing about onDestroy method, it doesn't get called all time. You mustn't rely on it.

Specify please what are you trying to achive and I'll try to offer better solution.

Suggestion

So, if I understood you right, I can suggest one thing. Start a Service that will fire LocalBroadcast every N seconds (it's not really heavy to system). Register and BroadcastReceiver for this broadcast in Activities. This way you'll get true or false depending on if there is any BroadcastReceiver that can catch your LocalBroadcast. And if no receivers than check for some SharedPreferences value that indicates if Button was pressed.