问题:

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 is password protected, this overview might show sensitive data in that snapshot. So is there any way to force a certain image (like a logo) to be shown rather than let the OS decide?

回答1:

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

回答2:

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.