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Ext Js Attach Event Handler In Parent Container To Its Child Item

A component definition:
Ext.define('Retroplanner.view.dimension.DimensionMapping', {
alias: 'widget.dimensionMapping',
extend: 'Ext.form.Panel',
...
items: [{
xtype: 'combo'
}, ...
]
A 'select' handler of the child item must create a widget and add this widget to the items array of its parent.
Inside of this child item, it its 'select' handler, I can find its parent by some search techniques. But I would like to avoid it if it is possible. I do not have a reference variable to the parent neither.
A better approach would be - to create function in the parent, and attach it somehow to the child item:
Ext.define('Retroplanner.view.dimension.DimensionMapping', {
...
onSiRemoteCombo: function(cmb, rec, idx) {
alert("select handler");
var newItem = Ext.widget('somexType');
this.items.add(newItem);
}
The question, how to attach onSiRemoteCombo?
I've found a similar solution here: How to create listener for child component's custom event
First, it does not work for me. I can give a full example that I tried to use.
2nd, I would like to create items via the most common way/in the common place, not via initComponent method. I would like to have something like:
Ext.define('Retroplanner.view.dimension.DimensionMapping', {
...
afterRender: function() {
var me = this;
//exception here
//Uncaught TypeError: Cannot read property 'on' of undefined
me.items[0].on('select', onSiRemoteCombo, this);
},
items: [{
xtype: 'combo'
}, ...
],
onSiRemoteCombo: function(cmb, rec, idx) {
alert("Ttt");
var dimensionMapping = Ext.widget('propGrid');
this.getParent().add(dimensionMapping);
}
But I get an exception:
//exception here
//Uncaught TypeError: Cannot read property 'on' of undefined
me.items[0].on('select', onSiRemoteCombo, this);
And also, attach a listener after each rendering, really is a bad idea.
Are there any best practices for such use cases? Ideally, if it will work in different versions of Ext JS, at least in 5.x and 6.x
Attach a handler in a child and access its parent? A child should not depend on its parent. Only parent should know, what to do.

One way to solve this is by wrapping the combo item component initialization into form's initComponent method. This way when setting a listener for the combo, you can use this.formMethod to reference a form method. Here is some code:
Ext.define('Fiddle.view.FirstForm', {
extend: 'Ext.form.Panel',
bodyPadding: 15,
initComponent: function () {
Ext.apply(this, {
items: [{
xtype: 'combo',
fieldLabel: 'First Combo',
store: ['first', 'second'],
listeners: {
'select': this.onComboSelect
}
}]
});
this.callParent();
},
onComboSelect: function () {
alert('I am a first form method');
}
});
The second approach by using a string listener on the combo, and by setting defaultListenerScope to true on the form. This way the listener function will be resolved to the form's method. Again, some code:
Ext.define('Fiddle.view.SecondForm', {
extend: 'Ext.form.Panel',
bodyPadding: 15,
defaultListenerScope: true,
items: [{
xtype: 'combo',
fieldLabel: 'Second Combo',
store: ['first', 'second'],
listeners: {
'select': 'onComboSelect'
}
}],
onComboSelect: function () {
alert('I am a second form method');
}
});
And here is a working fiddle with both approaches: https://fiddle.sencha.com/#view/editor&fiddle/27un

Show/hide subpanels dynamically in Ext JS

I have created a view (a panel) with 3 subpanels ...
When the view loads , I want a function to run in viewController and based on its outcome , I want subpanel 1 to be visible(subpanel2 to be invisible) or subpanel2 to be visible(subpanel1 to be invisible)
How can I accomplish this ?

You are looking for card layout. It is already implemented. So you don't have to implement again. Just tell it witch panel gonna be active it will do all layout things itself. Checkout this api doc.

May be the Accordion layout can help you:
This is a layout that manages multiple Panels in an expandable accordion style such that by default only one Panel can be expanded at any given time

Here's a full example, it's quite straight forward:
Fiddle
Ext.define('FooController', {
extend: 'Ext.app.ViewController',
alias: 'controller.foo',
init: function(view) {
var child = Math.random() < 0.5 ? 'p1' : 'p2';
view.setActiveItem(this.lookupReference(child));
}
})
Ext.define('Foo', {
extend: 'Ext.container.Container',
layout: 'card',
controller: 'foo',
items: [{
title: 'P1',
reference: 'p1'
}, {
title: 'P2',
reference: 'p2'
}]
});
Ext.onReady(function() {
new Foo({
renderTo: document.body,
width: 200,
height: 200
});
});

Give itemId to all three panel and then fireEvent.
Listener of view
listeners:{
show: function(){
me.fireEvent('showHidePanel');
}
}
define showHidePanel method in Controller and in that method get panel by using down() with item id and hide/show panel by using hide()/show() method.

Sencha Touch 2: How to override back button on Navigation View

I was wondering how to ovverride the back button on a navigation view. I tried using onBackButtonTap but it doesnt seem to work http://www.senchafiddle.com/#8zaXf
var view = Ext.Viewport.add({
xtype: 'navigationview',
onBackButtonTap: function () {
alert('Back Button Pressed');
},
//we only give it one item by default, which will be the only item in the 'stack' when it loads
items: [
{
//items can have titles
title: 'Navigation View',
padding: 10,
//inside this first item we are going to add a button
items: [
{
xtype: 'button',
text: 'Push another view!',
handler: function() {
//when someone taps this button, it will push another view into stack
view.push({
//this one also has a title
title: 'Second View',
padding: 10,
//once again, this view has one button
items: [
{
xtype: 'button',
text: 'Pop this view!',
handler: function() {
//and when you press this button, it will pop the current view (this) out of the stack
view.pop();
}
}
]
});

The fiddle you've mentioned works well in my local project on my machine. For some reason, it doesn't work on fiddle site. Try running it on your local project.
Still instead of using onBackButtonTap config, it's good to extend Ext.navigation.View class and override onBackButtonTap method. That way you'll have more control over whole components. You'd also like to override other configs as well. Here's what I'd use -
Ext.namespace('Ext.ux.so');
Ext.define('Ext.ux.so.CustomNav',{
extend:'Ext.navigation.View',
xtype:'customnav',
config:{
},
onBackButtonTap:function(){
this.callParent(arguments);
alert('back button pressed');
}
});
the line this.callParent(arguments) will allow component to behave in default way + the way to wanted it to behave. And if you want to completely override the back button behavior you can remove this line. Try doing both ways.
To use this custom component, you can use -
launch: function() {
// Destroy the #appLoadingIndicator element
Ext.fly('appLoadingIndicator').destroy();
var view = Ext.create('Ext.ux.so.CustomNav', {
fullscreen: true,
items: [{
title: 'First',
items: [{
xtype: 'button',
text: 'Push a new view!',
handler: function() {
//use the push() method to push another view. It works much like
//add() or setActiveItem(). it accepts a view instance, or you can give it
//a view config.
view.push({
title: 'Second',
html: 'Second view!'
});
}
}]
}]
});
}
Give this a shot. It'll work for you yoo.

Defining items of an object inside the initialize function

I am trying to create items inside a component as it gets initialized, with a function.
Consider the following:
Ext.define('mobi.form.Login',{
extend:'Ext.form.Panel',
config:{
items: [{
xtype: 'textfield',
name: 'Name',
label: 'Name'
}]
});
Ext.application({
viewport: {
layout:'fit'
},
launch: function(){
Ext.Viewport.add(Ext.create('mobi.form.Login'));
}
})
I am trying to get The mobi.form.login to generate its config from a function that runs on initialize ( or whatever I can use to over write the config I specify ).
I know Sencha touch 2 has the constructor, and initialize function, but both of them seem to have arguments=[] ( eg an empty array )
This is more or less how it would look if I was doing it in ExtJS 4.x:
Ext.define('mobi.form.Login',{
extend:'Ext.form.Panel',
initComponent:function(config){
config=Ext.apply({}.config,{});//make sure config exists
config.items= [{
xtype: 'textfield',
name: 'Name',
label: 'Name'
}]
Ext.apply(this, config);
this.callParent(arguments);
}
});

If you ever wanted to do this, you could use constructor or initialize.
Constructor you would use for synchronous logic which will be fast and you want to happen before the component is initialized. You can access the configuration through the constructors first argument:
Ext.define('MyComponent', {
extend: 'Ext.Component',
constructor: function(config) {
console.log(config);
this.callParent([config]);
}
});
Ext.application({
launch: function(){
Ext.create('MyComponent', { test: 1 })
// Will log out:
// {
// test: 1
// }
}
});
Remember you will always need to callParent with the config/arguments within constructor.
In any other situation, you should use initialize which is called after all the config's have been... initialized. :) We use this a lot internally for adding listeners.
initialize: function() {
this.on({
...
});
}

you don't need to call initialize manually it is already done by constructor and when calling this function you can access items data using this.items and create panel items there
Ext.define('mobi.form.Login',{
extend:'Ext.form.Panel',
config: {
items: []
},
initialize : function()
{
this.items = [Ext.create({
xtype: 'textfield',
name: 'Name',
label: 'Name'
})];
this.callParent();
}
});
Ext.application({
viewport: {
layout:'fit'
},
launch: function(){
Ext.Viewport.add(Ext.create('mobi.form.Login'));
}
})

Use the following:
Ext.apply(this, {
items: [
....
]
});

Have you tried something similar to this? I'm just passing a config object to Ext.create, though I can't test it right now. See http://docs.sencha.com/touch/1-1/#!/api/Ext-method-create
Ext.Viewport.add(Ext.create(
{
xtype: 'mobi.form.Login',
items: [ /*A list of items*/ ]
}
));
You could stick this snippet in its own function as well, one that takes in items as a parameter. Hope this solves your problem!

Sencha Touch 2 - TabPanel does not work in MVC designed App

simple question for you today...
This works:
var carousel = Ext.create('Ext.Carousel', {
fullscreen: 'true',
//load in views view clean instantiation using
// the widget.alias's defined in each view... yea
// For some reason, putting flex on these components... oh...
// Have to call directly in by just the xtype since these are just
// references..
items: [
{
xtype: 'Main'
},
{
xtype: 'CommentList'
}
]
This does NOT work:
var tabpanel = Ext.create('Ext.TabPanel', {
fullscreen: 'true',
tabBarPosition: 'bottom',
defaults: {
styleHtmlContent: true
},
//load in views view clean instantiation using
// the widget.alias's defined in each view... yea
// For some reason, putting flex on these components... oh...
// Have to call directly in by just the xtype since these are just
// references..
items: [
{
xtype: 'Main',
title: 'The Main',
iconCls: 'user'
},
{
xtype: 'CommentList',
title: 'Comments',
iconCls: 'user'
}
]
});
As you can see, they are pretty much the same except one is a TapPanel (with the required default configs added) and the other is a carousel.
Everything else is exactly the same.... This is in the app.js of my Sencha Touch 2.0 app designed following the MVC architecture.
The result of the not-working TabPanel is that I only see the first view (Main) and no tab-bar appears in the bottom of the screen.
Any ideas what my problem might be?

I am not sure if this is an issue but in my code the line is:
Ext.create("Ext.tab.Panel", {
Not:
Ext.create('Ext.TabPanel', {

Fullscreen should be fullscreen: true instead of fullscreen: 'true'. You could also add this code to make them switch:
cardSwitchAnimation: {type: "fade", duration: 1000},
layout: "card",
Didn't test it, but it worked for me (got it from a snippet of my own code)