Activity Lifecycle mismatch when turning off the display

Question

To solve some problems regarding App pause/resume, I tested the Activity Lifecycle by following simple App:

public class MainActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.content_main);
        Log.w("xxx", "create");
    }

    @Override
    public void onStart(){
        super.onStart();
        Log.w("xxx","start");
    }

    @Override
    public void onResume(){
        super.onResume();
        Log.w("xxx","Resume");
    }

    @Override
    public void onPause(){
        super.onPause();
        Log.w("xxx","pause");
    }

    @Override
    public void onDestroy(){
        super.onDestroy();
        Log.w("xxx","destroy");
    }

    @Override
    public void onStop(){
        super.onStop();
        Log.w("xxx","stop");
    }

    @Override
    public void onRestart(){
        super.onRestart();
        Log.w("xxx","restart");
    }
}

with a simple layout containing a Textview.

I installed the app and ran it:

01-28 11:56:09.032 2517-2517/android.se.behy.test W/xxx: create
01-28 11:56:09.035 2517-2517/android.se.behy.test W/xxx: start
01-28 11:56:09.035 2517-2517/android.se.behy.test W/xxx: Resume

and turned the display off (by pushing the on/off button) and surprisingly saw the following log:

01-28 11:56:09.032 2517-2517/android.se.behy.test W/xxx: create
01-28 11:56:09.035 2517-2517/android.se.behy.test W/xxx: start
01-28 11:56:09.035 2517-2517/android.se.behy.test W/xxx: Resume

01-28 11:56:20.750 2517-2517/android.se.behy.test W/xxx: pause
01-28 11:56:20.753 2517-2517/android.se.behy.test W/xxx: stop
01-28 11:56:20.809 2517-2517/android.se.behy.test W/xxx: destroy
01-28 11:56:20.843 2517-2517/android.se.behy.test W/xxx: create
01-28 11:56:20.844 2517-2517/android.se.behy.test W/xxx: start
01-28 11:56:20.844 2517-2517/android.se.behy.test W/xxx: Resume
01-28 11:56:20.857 2517-2517/android.se.behy.test W/xxx: pause

Question

normally I expected just to pause the app when I turn the display off, but why stop, destroy, create, start, resume and pause after it?

score 1 · Accepted Answer · answered Jan 28 '16 at 11:13

1

I think that your orientation changes when you are turning the display off. Most phones display the screenlock only in portrait mode. So before locking the screen, it rotates to orientation, and this configuration change is also applied to your app, which gets recreated because of this.

Try doing the same when your app is in portrait mode, it should work as expected.

To avoid recreating the activity on a configuration change, have a look at android:configChanges.

answered Jan 28 '16 at 11:13

Daniel Zolnai

16,487
7
59
71

thats correct, you mean I should change the orientation to portrate in onPause() method (because my app should run in Landscape mode)? – Behy Jan 28 '16 at 11:36
No, you should use `configChanges` for example. See this answer about the options you have: http://stackoverflow.com/a/5913370/1395437 – Daniel Zolnai Jan 28 '16 at 11:37

score 0 · Answer 2 · answered Jan 28 '16 at 11:12

0

Check you developer option in which in apps section there is option Don't keep activities if that is checked it will happen

answered Jan 28 '16 at 11:12

Ajinkya

1,057
7
18

Activity Lifecycle mismatch when turning off the display

2 Answers2