android - Why onRestoreInstanceState() never gets called

Question

I am trying to save data in my activity and than restore it. I save data in on onSaveInstanceState() and then I try to restore the data in onRestoreInstanceState().

I setup breakpoint, the method onSaveInstanceState() get called. But onRestoreInstanceState() or onCreate() never did.

Here is my steps:

1. start my Activity.
2. press 'Home' button on the phone. onSaveInstanceState() get called.
3. Click the icon in the launcher and launch my Activity again.

At this time, only onRestart() get called. But not onRestoreInstanceState() or onCreate().

Does anyone know why?

Answer 1

From doc:

The system calls onRestoreInstanceState() only if there is a saved state to restore.