title: How to apply Theme.Wallpaper at runtime on android?
body: <p>I use following code :</p>
  
  <pre><code>public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setTheme(android.R.style.Theme_Wallpaper);
      setContentView(R.layout.main);
  }
  </code></pre>
  
  <p>But it does nothing!</p>
  
  <p>How can I apply Theme.Wallpaper at runtime on android?</p>