Ext JS 6.5.1 - Modern Toolkit 
 
Ext.app.Controller | Ext JS 6.5.1 Docs Help Contents Terms, Icons, and Labels Access Levels Member Types Member Syntax Member Flags Summary Controllers are the glue that binds an application together. That said, their main purpose is to listen for events (usually from views) and take some action. Here's how we might create a Controller to manage Users: Ext.define('MyApp.controller.Users', { extend: 'Ext.app.Controller', init: function() { console.log('Initialized Users! This happens before ' + 'the Application launch() function is called'); } }); The init function is a special method that is called when your application boots. It is called before the Ext.app.Application's launch function is executed. This creates an area you can run code prior to Viewport creation. The controller's method-control function makes it easy to listen to events on your view classes and take some action with a handler function. Let's update our Users controller to tell us when the panel is rendered:

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