How to hide last activity view in android recent list? Using a locker screen implementation

Question

I am using an implementation of locker screen which locks (is displayed on top) the current activity when it is idle for X seconds. However the view for the locker activity is not displayed in the preview image after clicking the Home and Recent buttons.

enter image description here

How could I force to make my app's view blank or display my locker view in the recent list? I could set my activity visible to gone, but is there any other solution?

Best solution might be found here http://stackoverflow.com/questions/9822076/how-do-i-prevent-android-taking-a-screenshot-when-my-app-goes-to-the-background — deadfish, Feb 11 '13 at 13:37

score 7 · Answer 1 · answered Feb 06 '18 at 08:38

Try FLAG_SECURE:

public class FlagSecureTestActivity extends Activity {
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE,
                         WindowManager.LayoutParams.FLAG_SECURE);

    setContentView(R.layout.main);
  }
}

It will automatically display a grey background when Recents button is pressed.

A possible side-effect would be that you cant take the screenshot of the activity you are defining this way.

score 2 · Accepted Answer · answered Feb 08 '13 at 10:59

2

Try the attribute, android:noHistory="true" for the activity tag in the manifest file.

answered Feb 08 '13 at 10:59

Gopinath

12,981
6
36
50

It destroys trace unfortunately. I want just see blank preview for my app. Think in this way: you pasted in plain text password on your activity and you don’t want see this text in preview list last opened apps. Besides, destroying trace sounds like hack, not solution. – deadfish Feb 08 '13 at 11:09
Override onStop() method and just try resetting the content view of your activity to some blank xml file before you call super.onStop(). Probably, Android framework will make a screenshot of your app for showing in the recent apps when activity.onStop() is called! – Gopinath Feb 08 '13 at 11:20
@deadfish Did you got any proper solution? – Alvin Varghese Jun 20 '17 at 09:39
@nope, however native Google Alarm Clock app might give You a tip. Look how it behaves when alarm runs. – deadfish Jun 20 '17 at 11:38

score 0 · Answer 3 · answered Feb 08 '13 at 10:55

The recents app gets something like a "screenshot" when the app goes to background, so before go to background you can fill your activity with a black LinearLayout and onResume check if this LinearLayout is showing and hide. Maybe there are better solutions but this may works.

How to hide last activity view in android recent list? Using a locker screen implementation

3 Answers3

Linked