How to change the snapshot shown by recent apps list?

Question

In the newer versions of Android (> 3.0) there is an onscreen button that will display a list of the recent apps with their names and snapshots. Even though my app itself

Answer 1

The solution provided by Azat continues to be valid also in Lollipop.

Just a note, if you want to continue to not see snapshots in recent list for the entire app, ALL the implemented activities should specify in the onCreate() method the flag getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE); before setContentView();

Otherwise a snapshot in the recent list will show the first activity without the flag if the user navigated through it.

Answer 2

It seems to be impossible for now. There's a method called onCreateThumbnail but it is not used currently by the system I guess, since it is not called. I see two possible solutions:

1. To disable thumbnail on the activity containing sensitive data by adding FLAG_SECURE to your window: getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
2. To exclude your activities from recent apps, set android:excludeFromRecents attribute to true for activities in AndroidManifest.xml