title: Java, JFrame: getWidth() returns 0
body: <pre><code>setExtendedState(getExtendedState()|JFrame.MAXIMIZED_BOTH);
  setResizable(false);
  setUndecorated(true);
  System.out.println("--------&gt; "+getContentPane().getWidth()); //----&gt; 0 why is this happening?
  </code></pre>
  
  <p>I'm trying to determine the size of a JFrame. I've searched on google and checked the documentation and I still don't know why it won't work
  It works fine on about any other control I try it on</p>
  
  <p>EDIT:
  frame.getWidth() works when called outside of the class (that extends JFrame)
  still, if I replace</p>
  
  <pre><code>System.out.println("--------&gt; "+getContentPane().getWidth());
  </code></pre>
  
  <p>with</p>
  
  <pre><code>System.out.println("--------&gt; "+this.getWidth());
  </code></pre>
  
  <p>getWidth will still return 0</p>
  
  <p>EDIT2:
  I need the frame's size before setting it visible and stuff. I need to add other controls to the frame and their coordinates and size depend on the frame's size.</p>