ViewTreeObserver_Ex.java

//inside a fragment. If in an Activity you could use findViewById(Window.ID_ANDROID_CONTENT);
getView().getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener()
{
    @Override
    public void onGlobalLayout()
    {
        //do something like measure a view etc
        View content = getWindow().findViewById(Window.ID_ANDROID_CONTENT);
        Log.d("DISPLAY", content.getWidth() + " x " + content.getHeight());
        
        //we only wanted the first call back so now remove
        if(Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN)
            getView().getViewTreeObserver().removeGlobalOnLayoutListener(this);
        else
            getView().getViewTreeObserver().removeOnGlobalLayoutListener(this);
    }
});