Book Image

Ext JS 3.0 Cookbook

Book Image

Ext JS 3.0 Cookbook

Overview of this book

Using Ext JS you can easily build desktop-style interfaces in your web applications. Over 400,000 developers are working smarter with Ext JS and yet most of them fail to exercise all of the features that this powerful JavaScript library has to offer. Get to grips with all of the features that you would expect with this quick and easy-to-follow Ext JS Cookbook. This book provides clear instructions for getting the most out of Ext JS with and offers many exercises to build impressive rich internet applications. This cookbook shows techniques and "patterns" for building particular interface styles and features in Ext JS. Pick what you want and move ahead. It teaches you how to use all of the Ext JS widgets and components smartly, through practical examples and exercises. Native and custom layouts, forms, grids, listviews, treeviews, charts, tab panels, menus, toolbars, and many more components are covered in a multitude of examples.The book also looks at best practices on data storage, application architecture, code organization, presenting recipes for improving themóour cookbook provides expert information for people working with Ext JS.
Table of Contents (15 chapters)
Ext JS 3.0 Cookbook
Credits
About the Author
About the Reviewer
Preface

Implementing a publish/subscribe mechanism with relayEvents()


In this recipe, you'll learn how to implement a publish/subscribe mechanism, where a component listens to events generated from within other components. A very simple console listens to events that occur inside two panels, as seen in the following screenshot:

How to do it...

  1. 1. Create a namespace for your code and define a utility function that will be used by your event-handling routines:

    Ext.ns('Dashboard');
    function WriteToConsole(console, msg) {
    var prevValue = console.getValue();
    if (null == prevValue) prevValue = '';
    console.setValue(prevValue + msg);
    }
    
  2. 2. Create a Portlet class as an extension of Ext.Panel:

    Dashboard.Portlet = Ext.extend(Ext.Panel, {
    anchor: '100%',
    frame: true,
    collapsible: true,
    draggable: true,
    
  3. 3. Add some tools to the Portlet class and attach the click handlers to each tool. The click handlers will fire the custom events defined in the next step:

    tools: [{
    id: 'gear',
    handler: function(e, toolEl, panel...