 <p>Declare every view , controller , model , store whatever you are using in ur application in <code>app.js</code>:</p> <pre><code>Ext.application({ name: 'AppName', requires: [], models:['Model-1','Model-2'], controllers : ['Main'], views : ['View-1','View-2'], stores : [ 'Store-1' , 'Store-2'], launch : function() { Ext.fly('appLoadingIndicator').destroy(); Ext.Viewport.add({ xclass: 'AppName.view.View-1', autoDestroy: false, showAnimation:false }); } }); </code></pre>