Overscroll effect in gallery class android?

How to implement overscroll effect in gallery class android?

setOverScrollMode(OVER_SCROLL_IF_CONTENT_SCROLLS);

I try to override

@Override
protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boo开发者_JS百科lean clampedY) 
{
    System.out.printf("onOverScrolled\n");
}

but no output

System.out.printf() does nothing on Android, I believe. To output something like that, use Log.i() and look in Eclipse in the DDMS view. I personally use Log.e() because it isn't constantly being printed to like i and d, but since it's not technically an error, it's bad form.