Question

I Want to make the my Button go invisible or gone a few seconds after the activity is created. Using a thread gave me this error

The Error is in here :

android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

Then I tried using a Handler, this gave me this error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.LstSearch/com.LstSearch.BasicMusicView}: java.lang.NullPointerException

So then I tried using runOnUiThread(). If I execute this in onCreate(), the activity takes the amount of time as I have specified in the thread, and the image will go invisible after that much time. But when the activity starts after 3 seconds, the image has already turned itself invisible.
I think have found the Solution as a new entry they are not allowing me to answer me question so i am editing here

handler=new Handler();
 Runnable r=new Runnable() 
{ public void run() 
{change image } 
};
 handler.postDelayed(r, 1000);

Cheers!!

Answer 1

you need to call the invisibility function on the UIThread(), you can though views only in UIThread.

user runonUIthread() method.