title: android setBackgroundDrawable is not working
body: <p>This one 12 hours debugging..help me..</p>
  
  <p>res/drawable</p>
  
  <pre><code>    main_img1.png
      main_img2.png
  </code></pre>
  
  <p>xml</p>
  
  <pre><code>    android:background="@drawable/main_img1"
  </code></pre>
  
  <p>Member</p>
  
  <pre><code>    RelativeLayout relativelayout;
  </code></pre>
  
  <p>oncreate</p>
  
  <pre><code>    relativelayout = new RelativeLayout(this);  
      relativelayout.setBackgroundDrawable(getResources().getDrawable(R.drawable.main_img2));
      relativelayout.invalidate();
  </code></pre>
  
  <p>image is not change
  setBackgroundDrawable is not working
  no error no redline</p>
  
  <p>You can not use an imageview,<br/>
  the change dynamically to the background of the layout, the handler</p>
  
  <p>Please share your knowledge</p>