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ExtJS4 - Define Global objects in MVC pattern with example!


Example 1:
Define separate new global class and use them across all views in EXTJS MVC pattern

Ext.define('MyApp.util.Utilities', {
     singleton: true,
     SomeValue: 1,
     SomeText: 'First'
});
 //override global instance with new values
 MyApp.util.Utilities.SomeValue = 5;
 MyApp.util.Utilities.SomeText = 'Hello World!';


Example 2 : Use of statics

Ext.define('MyApp.Utilities', {
    statics: {
        foo: function (a, b) {
            return a + b;
        }
    }
});

Ext.define('MyApp.MyView', {
    extends: 'Ext.panel.Panel',
    requires: ['MyApp.Utilities'],

    initComponent: function () {
        MyApp.Utilities.foo(1, 2);
    }
});

Example 3:  Use of globals {} scope


  //App defined here
 Ext.application({
    name : 'MyFiddle',
   // we can also define global variables which are used throughout the app
    globals:{
        myURL:'http://example.com',
        myName: 'Raja'
    },
    requires: ['MyApp.util.Utilities'], //Don't forget to require your class
    launch : function() {
        console.log('global var old value:'+ MyApp.util.Utilities.SomeValue);
        MyApp.util.Utilities.SomeValue = 2; //variables in singleton are auto static.
        console.log('MyFiddle', 'Global Var new value:'+ MyApp.util.Utilities.SomeValue);
       
        // access global var's        
        var somevalue = MyApp.util.Utilities.SomeValue;
        var sometext = MyApp.util.Utilities.SomeText;
        var someurl = MyFiddle.app.globals.myURL;
        var somename = MyFiddle.app.globals.myName;
        
        var str = 'SomeValue: '+somevalue+' ; SomeText: '+sometext+'; myURL: '+

            someurl+'; myName: '+somename;
        //panel def
        Ext.create('Ext.panel.Panel', {
            title: 'Statics Example',
            width: 600,
            height: 200,
            defaults: {
                // applied to each contained panel
                bodyStyle: 'padding:10px'
            },
            layout: {                
                type: 'fit'
            },
            html: str,            
            renderTo: Ext.getBody()
        });
    }
        
    });

http://jsfiddle.net/prajavk/YhuWT/
  

Example 4:

Ext.define('Wetter.utils.Global',{
    singleton: true,
    
    test: function(params) {
        alert("test"+params);
    },
});

Wetter.utils.Global.test('hello');



Example 5C:
This shows the contents of Runtime.js and example 5D shows how to “require” it in your app.js. You can then “set” and “get” your properties as shown in 5E and 5F from anywhere in the app.

Ext.define(‘MyApp.config.Runtime’,{
    singleton : true,
    config : {
        myLastCustomer : 0   // initialize to 0
    },
    constructor : function(config){
        this.initConfig(config);
    }
});

Example 5C. Sample Runtime.js file to hold global properties for an app.

Ext.application({
    name : ‘MyApp’,
    requires : [‘MyApp.config.Runtime’],
   ...
});

Example 5D. Require the Runtime class in your app.js file.

MyApp.config.Runtime.setMyLastCustomer(12345);

Example 5E. How to set the last customer.

MyApp.config.Runtime.getMyLastCustomer();

Example 6:

As a rule of thumb, we should avoid using global variables as much as possible. Though sometimes it's very convenient to use them. One such global I used to manage frequently used 'Loading...', 'Updating...' type of messages in overlays.

This is how we defined the global variable 'mask' in app.js

Ext.define('mask', {
            singleton: true,
            loading: new Ext.LoadMask(Ext.getBody(), {msg:"Loading...."}),
            updating: new Ext.LoadMask(Ext.getBody(), {msg:"Updating...."}),
            saving: new Ext.LoadMask(Ext.getBody(), {msg:"Saving...."}),
            working: new Ext.LoadMask(Ext.getBody(), {msg:"Working...."})
});

Now we can use this variable anywhere in our code, i.e. in views or in controllers.

//this will show a loading message in overlay
//can be called in view or in some controller function
mask.loading.show();


//this will remove the loading message
//generally called in a controller function, most probably inside a Ajax request's callback
mask.loading.hide();


This global will save you to create LoadMasks everytime you want to show some message in overlay.

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