title: How to handle back button in sencha touch application without NavigationView?
body: <p>I have googled, but all the useful articles are all describing how to handle the back button in NavigationView, but I just use the common view like below.</p>
  
  <pre><code>Ext.define('emall.view.MyPage', {
      extend: 'Ext.Container',
      alias: 'widget.mypage',
  
      requires: [
          'emall.view.topplus',
          'Ext.TitleBar',
          'Ext.Button',
          'Ext.Toolbar'
      ],
  </code></pre>
  
  <p>I am do changes on the existing app, so I can not change the base architecture.
  So I am wondering how to handle the back button?</p>
  
  <p>I know below way can capture the back button event.(I added the below method to app.js)</p>
  
  <pre><code>if (Ext.os.is('Android')) {
      document.addEventListener("backbutton", Ext.bind(onBackKeyDown, this), false);
  
      function onBackKeyDown(eve) {
  
          eve.preventDefault();
          //do something
          alert('back button pressed');
          history.back();  
  
      }
  }
  </code></pre>
  
  <p>But what can I do in the method <strong>onBackKeyDown</strong>? Since this event will be fired when I click the back button no matter which page I am staying. So I can not go to the previous page like <strong>Ext.Viewport.animateActiveItem('xxxx')</strong> since I do not know the current page I am staying.</p>
  
  <p>If I can get the current page name, I can handle it like below.</p>
  
  <pre><code>if(currentpage=='xxx')
              Ext.Viewport.animateActiveItem('profile', {
                  type : 'slide',
                  direction:'left'
              });
  </code></pre>