Attach ExtJS MVC controllers to DOM elements, not components

Question

Is there a way to use the Ext.app.Controller control() method, but pass in a DOM query? I have a page that contains standard links and would like to add a click handler to

Answer 1

I asked this question at SenchaCon this year, the Sencha developers stated that their intent is that DOM listeners should be attached within your view, and the view should abstract them into more meaningful component events and refire them.

For example, suppose you're creating a view called UserGallery that shows a grid of people's faces. Within your UserGallery view class, you would listen for the DOM click event on the tag to receive event and target, and then the view might fire a component event called "userselected" and pass the model instance for the clicked user instead of the DOM target.

The end goal is that only your views should be concerned with things like interface events and DOM elements while the application-level controller only deals with meaningful user intents. Your application and controller code shouldn't be coupled to your markup structure or interface implementation at all.

Sample View

Ext.define('MyApp.view.UserGallery', {
    extend: 'Ext.Component'
    ,xtype: 'usergallery'

    ,tpl: ''

    ,initComponent: function() {
        this.addEvents('userselected');

        this.callParent(arguments);
    }

    ,afterRender: function() {
        this.mon(this.el, 'click', this.onUserClick, this, {delegate: 'img'});

        this.callParent(arguments);
    }

    ,onUserClick: function(ev, t) {
        ev.stopEvent();

        var userId = Ext.fly(t).getAttribute('data-ID');

        this.fireEvent('userselected', this, userId, ev);
    }
});

Notes on views

• Extend "Ext.Component" when all you want is a managed
  , Ext.Panel is a lot heavier to support things like titlebars, toolbars, collapsing, etc.
• Use "managed" listeners when attaching listeners to DOM elements from a component (see Component.mon). Listeners managed by a components will be automatically released when that component gets destroyed
• When listening for the same event from multiple DOM elements, use the "delegate" event option and attach the listener to their common parent rather than to individual elements. This performs better and lets you create / destroy child elements arbitrarily without worrying about continuously attaching/removing event listeners to each child. Avoid using something like .select('img').on('click', handler)
• When firing an event from a view, Sencha's convention is that the first parameter to the event be scope -- a reference to the view that fired the event. This is convenient when the event is being handled from a controller where you'll need the actual scope of the event handler to be the controller.

Sample Controller

Ext.define('app.controller.myController', {
    extend: 'Ext.app.Controller'

    ,init: function() {
        this.control({
            'usergallery': {
                userselected: function(galleryView, userId, ev) {
                    this.openUserProfile(userID);
                }
            }   
        });
    }

    ,openUserProfile: function(userId) {
        alert('load another view here');
    }
});