Android: Calling non-static methods from a static Handler class

Question

Given this code:

public class MainActivity extends FragmentActivity implements ActionBar.TabListener {

public static final int MESSAGE_NOT_CONNECTED = 1;

@Over         


        

Answer 1

In my activity's onDestroy method I call:

this.myHandler.removeCallbacksAndMessages(null);

This does not get rid of the "This Handler class should be static or leaks might occur" warning, but I believe it destroys the message hence stopping the leak. My handler class is an inner non-static class of my activity. My activity has an instance of MyHandler myHandler.

When I do this, the handler's handleMessage method isn't called, which I assume means that the message containing the handler, which contained a reference to the activity was destroyed. Am open for comments as I haven't tested it with any leak testing tools. Here is where I copied the idea: http://www.androiddesignpatterns.com/2013/01/inner-class-handler-memory-leak.html answerer: CyrilJanuary 15, 2013 at 7:50 AM

Answer 2

Try using a WeakReference, as described in this article.

Answer 3

Since you are now using a WeakReference, mTarget.get() might return null. In your edited code, you are not checking if target is null before executing target.setStatus(R.string.title_not_connected). So this may throw a NullPointerException if the weakreference object has been GC'ed.