Extjs 继承的使用

Javascript原始的继承写法：

// Traditional constructor:
Ext.Foo = function(config){
	// call superclass constructor:
    Ext.Foo.superclass.constructor.call(this, config);

    this.addEvents({
		// add events
    });
};
Ext.extend(Ext.Foo, Ext.Bar, {
   // class body
}

Extjs中替换constructor，写法如下：

// initComponent replaces the constructor:
Ext.Foo = Ext.extend(Ext.Bar, {
    initComponent : function(){
		// call superclass initComponent
        Ext.Container.superclass.initComponent.call(this);

        this.addEvents({
            // add events
        });
    }
}