Book Image

Ext JS 4 Plugin and Extension Development

By : Abdullah Al Mohammad
Book Image

Ext JS 4 Plugin and Extension Development

By: Abdullah Al Mohammad

Overview of this book

Ext JS is a pure JavaScript application framework for building interactive web applications using techniques such as Ajax, DHTML, and DOM scripting. Ext JS 4 Plugin and Extension Development is a practical, step-by-step tutorial which guides you to learn and develop ExtJS plugins and extensions. There are a lot of examples with explanations and plenty of code provided to make it easier and quicker to pick up. Starting with the fundamentals, this book introduces some of the ExtJS library and community provided plugins and extensions and finishes with several hands-on, real world development examples. You will get a clear concept of ExtJS plugins and extensions and learn how to use them. You will also learn how to develop an ExtJS plugin and extension by going through several examples with code and screenshots. Ext JS 4 Plugin and Extension Development book will provide you with the knowledge to develop ExtJS plugins and extensions using real-life examples.
Table of Contents (16 chapters)
Ext JS 4 Plugin and Extension Development
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Planning and coding the labeled spinner


To meet the functional requirements, we will create an extension class by extending the Ext JS's Ext.form.field.Spinner class from which we will get most of the facilities that we need to provide. We need to implement the onSpinUp and onSpinDown functions of the Ext.form.field.Spinner class to handle the spinner button click event to provide our logic to increase or decrease the values. By default, pressing the up and down arrow keys will also trigger the onSpinUp and onSpinDown methods. Now, let us start coding:

Ext.define('Examples.ux.LabeledSpinner', {
  extend : 'Ext.form.field.Spinner',
  alias : 'widget.labeledspinner',

  onSpinUp : function() {
    this.setValue(++this.value);
  },

  onSpinDown : function() {
    this.setValue(--this.value);
  }
});

And now we have a working extension that can increase or decrease its value. Here is the screenshot where we used this extension:

You can see that we now have a field with up/down spinner buttons...