title: Titanium: Trap android back button
body: <p>I'd like to capture the android back button to force confirmation before exiting the app. My app is a two window/two tab app, based on the skeleton that the titanium cli creates.  I've tried all three approaches below. As far as I can tell, the back button is never trapped, the app just closes when the back button is pressed.</p>
  
  <p>Titanium 3.2.0 CLI
  OS X 10.9</p>
  
  <pre><code>  // below true of all windows:
    // modal: true,
    // exitOnClose:true
    // android:back and androidback have been tried
  
  Ti.App.addEventListener('androidback', function(e){
      var confirmClear = Titanium.UI.createAlertDialog({
  
  
          message:'Exit App?', 
          buttonNames: ['Yes','No']
      });
      confirmClear.show();
      confirmClear.addEventListener('click',function(e) {
          if (e.index === 0) {
  
           win1.close();
  
            }
      });
  });
  
  //////////////////////////////////////////////////  
  
  win1.addEventListener('androidback', function(e){
      var confirmClear = Titanium.UI.createAlertDialog({
  
  
          message:'Exit App?', 
          buttonNames: ['Yes','No']
      });
      confirmClear.show();
      confirmClear.addEventListener('click',function(e) {
          if (e.index === 0) {
  
           win1.close();
  
            }
      });
  });
  
  //////////////////////////////////////////////////  
  
  win2.addEventListener('androidback', function(e){
      var confirmClear = Titanium.UI.createAlertDialog({
  
          message:'Exit App?', 
          buttonNames: ['Yes','No']
      });
  
      confirmClear.show();
  
      confirmClear.addEventListener('click',function(e) {
          if (e.index === 0) {
  
           win2.close();
  
            }
      });
  });
  </code></pre>
  
  <p>After reading the suggestions, here's my now working code:</p>
  
  <pre><code>tabGroup.addEventListener('androidback', function(e){
      var confirmClear = Titanium.UI.createAlertDialog({
  
  
          message:'Exit App?', 
          buttonNames: ['Yes','No']
      });
      confirmClear.show();
      confirmClear.addEventListener('click',function(e) {
          if (e.index === 0) {
  
           tabGroup.close();
  
  
            }
      });
  });
  </code></pre>