title: changing the layout of current activity
body: <pre><code>FrameLayout content = (FrameLayout) findViewById(android.R.id.content); 
  </code></pre>
  
  <p>This gives me an error</p>
  
  <pre><code>error: cannot find symbol
      FrameLayout rootLayout = (FrameLayout)findViewById(android.R.id.content);
                                            ^
  symbol:   method findViewById(int)
  </code></pre>
  
  <p>I have already imported the required R package</p>