Ext JS 4: Getters and setters in view

Question

I've been thinking about this problem for a while, and I can't seem to come up with a reasonable solution. What I would like to do is create getters/setters for a textfield/its value in my view. I realize that the preferred Ext JS way is using a reference within the controller and getting it that way, but that doesn't feel very object-oriented to me. I'd also have to wrap these getters and setters because I want to output a message if the getter returns undefined. What I'd like to do is create my own getters/setters or somehow override the default getters/setters. Here are some ways I was thinking of accomplishing this.

I was thinking I could use the config {}, but that appears to only work for variables I want to define. I then was thinking of using an id somehow, but the community seems split on whether that's a good practice or not. Which leads to my current solution... wrapping. Here's my code:

LoginWindow

Ext.define('MyApp.view.LoginWindow', {
    extend: 'Ext.window.Window',
    alias: 'widget.loginWindow',
    autoShow: true,
    closable: false,
    border: 0,
    plain: true,
    allowBlank: false,
    title: "Enter your username",
    modal: true,
    config: {
        buttons: [{
            text: "Ok"
        }],
        items: [{
            xtype: 'textfield',
            fieldLabel: 'Username',
            id: 'loginUserInput',
            name: 'loginUserInput',
            msgTarget: 'under',
            validator: function(value) {
                if (Ext.isEmpty(value)) {
                    return "You need to enter a username.";
                }
                return true;
            }
        }]
    },

    constructor: function(config) {
        this.callParent(config);
    },

    getButton: function() {
        console.log('here');
    }
});

MyController

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

    requires: [
        'Views.ChatModule.view.LoginWindow'
    ],

    refs: [{
        ref: 'loginWindow',
        selector: 'loginWindow',
        xtype: 'loginWindow',
        autoCreate: true
    }, {
        ref: 'loginUserInput',
        selector: '#loginUserInput'
    }],

    init: function() {
        // The events controller oversees
        this.control({
            'loginWindow button[text="Ok"]': {
                'click': this.onSubmitLoginWindow
            }
        });
    },

    getLoginUserInputValue: function() {
        var loginUserInput = this.getLoginUserInput();
        if (loginUserInput) {
            var username = loginUserInput.getValue();
            if (username) {
                console.log(username);
            } else {
                console.warn("username is undefined");
            }
        }
        console.warn("loginUserInput is undefined");
    },

    onSubmitLoginWindow: function(button, event, eOpts) {
        this.getLoginUserInputValue();
    }
});

This works, and I realize it's a very nit-picky thing, but it just doesn't feel right to have the getter in the controller. I feel like it'd be more object-oriented if it was in the Window. However, if I put it in the Window, I believe my only option is to lean on ids or manually create the textfield in the Window's initComponent--which would involve saving off a reference of the textfield in there, but that seems a bit inefficient... as I would have to make a call to doLayout as well.

Just to reiterate, I'd love to have the getters/setters in the Window, and I'm looking for a quick way to reference it, similar to how the controller references objects. I believe the main answer will be to use ids and making a call to Ext.ComponentQuery.query('#loginUserInput') in the Window, but I'd like to know if there were any better approaches out there... like overriding the auto generated getters/setters or adding a simple getter/setter for an input's value.

Cross-post from the Sencha forums.

Edit

I guess I was a bit unclear with what I want. As a more general statement, instead of jamming all things related to my view in the controller, I'd like to store it all in the view itself, which includes things like getters/setters. One of these getters/setters just so happens to be the loginUserInput getter.

Using a model is an interesting idea, but I feel like that would be a whole lot of overhead for singleton values. I'm basically looking for something like Java's setters/getters in the LoginWindow view... and hopefully something as simple as (or close to) Java's.

The idea of including (encapsulating) it in the view makes the controller a bit cleaner, and if I delete the view, I'm deleting its functions as well, so I don't have to go hunting for the functions in the controller... all I have to worry about is removing the references (which should be minimal).

Answer 1

My thoughts are something like this:

...
items: [],
constructor: function(config) {
  this.loginUserInput = Ext.create('Ext.form.field.Text', {
    fieldLabel: 'Username',
    id: 'loginUserInput',
    name: 'loginUserInput',
    msgTarget: 'under',
    validator: function(value) {
      if (Ext.isEmpty(value)) {
        return "You need to enter a username.";
      }
      return true;
    }
  });
  this.items.push(this.loginUserInput);
  this.callParent(config);
},

getLoginUserInput: function() {
  var loginUserInput = this.loginUserInput;
  if (!loginUserInput) {
    console.warn("LoginWindow::getLoginUserInput: loginUserInput is undefined");
  }
  return loginUserInput;
}

So instead of letting Ext do its magic, I am now instantiating the object on my own, which then allows me to store away a reference of it, so I can easily access it in my getter. I just wonder if this is creating any sort of performance hit. It doesn't seem like it'd be that much worse... it actually seems like it'd be a bit better because I'm not referencing this object by its ID, and I don't have to go searching for it when I need it.

Answer 2

I think that the "OO" way that you're looking is to work with a Ext.data.Model for your form. If you look at the Ext.form.Basic you have methods to manipulate a model (called record) and also get the object with the values of your view. So you need:

1. When you create your form, use loadRecord() to bind your form to a Model.
2. At any time you need, use getValues() to retrieve the values of your form fields.
3. When submiting your form, use getRecord() and getValues() to sync your record.

---

Ext.define('MyApp.model.Login',{
  fields : [{
    name: 'username',
    type: 'string'
  },{
    name: 'password',
    type: 'string'
  }]
});

Ext.define('MyApp.controller.Login',{
  ...
  refs : [{
    selector: 'window form',
    ref: 'formPanel'
  }],
  ...
  openForm : function() {
    //load your form and then bind the new record
    var formPanel = this.getFormPanel(), //Ext.form.Panel
        form = formPanel.getForm(); //Ext.form.Basic

    form.loadRecord(Ext.create('MyApp.model.Login'));

  },
  save : function() {
    //get the values in the view
    var form = this.getFormPanel().getForm(),
        vals = form.getValues(),
        record = form.getRecord();

    console.log(vals); //see the object representation of your view here
    record.set(vals); //update your model

    //do whatever you need with your model

  }
  ...
});

This is an good example when you need to save the form data. In the login I think you can work directly with getValues() without binding it to a Ext.data.Model.

Answer 3

I am not quite certain what problem you are trying to solve to be honest with you.

If you do not like controllers listening to buttons within your window, you can have button handlers witin your view definition fire custom events that controllers can listen on. Use fireEvent method. And by the way initConfig is a recommended way to setup your views. You can break it up into methods if you wish, 'this' reference is available and is the View component being instantiated.

If you need to find inner components within the View there are many methods available from up /down to nextSibling and query .

For Components:
    • Ext.getCmp(id)
    • Ext.ComponentQuery.query()
    • up() 
    • down() 
    • nextSibling() 
    • previousSibling()
    • child()
    • previousNode()
plus various find.. Methods

EDIT

I think I understood what you mean by getter and setters. Ext forms have the fields finders to make it easy to get and set data to individual fields. See these SO questions: Best way to access adjacent components / fields and EXT.JS getting a list of items from a fieldset

Also like Sergio said there is getRecord getValues and setRecord methods on the form to deal with data binding. Thats it.

EDIT2

The best starting point guide that shows clear and claen MVC patterns as well as form handling. http://docs.sencha.com/extjs/4.1.3/#!/guide/application_architecture