I've added an event like so:
this.getLetters().element.on({
tap: me.lettersTap,
delegate: 'span.letter-hidden'
});
based on user interaction, I'm adding another class to those
elements, so it will be:
<span class="letter-hidden new_class">
I want to remove the event handler based on the "new_class",but got no clue how.
I tried like:
questionController.getLetters().element.un({
tap: questionController.lettersTap,
delegate: 'span.new_class',
scope: questionController
});
but it's not working, I am able to remove it if I replace the "new_class" with letter-hidden in the above code, so I suppose works to be removed if the same class is used, which is not mentioned in documentation. Am I doing something wrong, an alternative would be nice to have it...Thanks.
You used a delegate so it would be important to use exactly the same when you are trying to remove it. Otherwise ExtJS must expect it is a different element, which is a correct behavior.
This is how the registered listeners get checked:
(registered.fn === remove.fn &&
registered.scope === remove.scope &&
registered.delegate === remove.delegate &&
registered.order === remove.order)
So no, there is no alternative way. You have to unregister with the same properties as you registered it.
Note: Sencha don't use your properties to query within the DOM it just
lookup in the oberservalbe listeners collection for a listener that
was registered like the one you handed to unregister.
Related
I am working on a problem wherein I am required to pick-up keydown events (specifically ctrl+p and then point to a print function which already exists) on a certain custom directive and under certain conditions (a certain tab should be selected). My current approach is to bind the keydown event on the document itself, broadcast it and then listen to it in the required custom directive. Following is the code I have placed in the app.run.. block -
angular.element($document).on('keydown', function(evt) {
if(evt.ctrlKey && evt.key==='p'){
$rootScope.$broadcast('printOnKeyPress');
}
});
This part is working as expected, the problem arises when I try to handle it in the required controller of the custom directive as follows:
$scope.$on('printOnKeyPress', function() {
//point to existing print function
}
This is where the problem arises. It goes into the print function but still the output is incorrect. I am missing something and I can't figure out what.
Also, this is not a good approach but I have searched and am unable to find a possible solution to just bind the keydown event on that custom directive itself (the component only appears if a document is selected).
(ng-keydown won't also work here)
Any help is appreciated!
You could put it in the directive and use the scope destroy event to remove the listener.
Within directive link function:
function keyHandler(evt) {
if (evt.ctrlKey && evt.key === 'p') {
// do your print
}
}
angular.element($document).on('keydown', keyHandler);
scope.$on('$destroy', function() {
angular.element($document).off('keydown', keyHandler);
});
I have a view which defines a change event on some select controls, but they don't seem to be firing. The view is something like this:
var FiltersView = Backbone.Marionette.ItemView.extend({
template: FiltersTmpl,
events: {
'change #panel_filters select': 'enableSearch'
},
enableSearch: function() {
debugger;
}
});
When I change the dropdown, enableSearch doesn't fire. However, using Chrome Dev Tools, I can use jQuery to setup an event handler like this $("#panel_filters select").change(function() { debugger; }); and that does in fact fire. So I know the selector is correct and the select is triggering a change event. I know it must be a simple syntax problem but it seems like the correct syntax to me.
Ok I figured it out. #panel_filters is actually the element that I injected my view into. Technically, it's considered outside the view. And apparently, view events are scoped to the view itself. Which is handy I suppose, but I didn't know that. Good to know :-)
I've binded window's scroll event to a view's method like:
MyView = Backbone.View.extend({
initialize: function(){
_.bindAll(this, 'handleScrolling');
$(window).off('scroll', this.handleScrolling).on('scroll', this.handleScrolling);
}
})
I see this is not working. If this callback is triggered as many times as this view is instantiated. However, if I remove handler from off, then it is correctly unbinding and triggers only once per scrolling. Like:
$(window).off('scroll').on('scroll', this.handleScrolling);
Any idea why this is happening? I dont want to remove all callbacks from this event as other views/codes may bind event to it which will make app behaving unexpected.
Is there any better way of binding events to window/document or other element outside the scope of current view?
Your problem is right here:
_.bindAll(this, 'handleScrolling');
That's equivalent to:
this.handleScrolling = _.bind(this.handleScrolling, this);
so each time you instantiate your view, you're working with a brand new function in this.handleScrolling. Then you do this:
$(window).off('scroll', this.handleScrolling)
But that won't do anything since the this.handleScrolling function that you attached with on:
.on('scroll', this.handleScrolling);
isn't the same function as the this.handleScrolling function that you're trying to .off. The result is that each time you create a new instance of your view, you're leaving the old scroll handler in place and adding a new one.
The proper solution (IMO) is to add a remove method to properly clean things up:
remove: function() {
$(window).off('scroll', this.handleScrolling);
return Backbone.View.prototype.remove.apply(this);
}
and then call view.remove() before creating the new view.
It looks like you have a new instance of the handler this.handleScrolling in each call.
so when jQuery tries to remove the specific handler it will not find the handler in the event registry, so it will not be able to remove it.
Problem: Demo
I would suggest using event namespaces here
$(window).off('scroll.myview').on('scroll.myview', this.handleScrolling);
Demo: Fiddle
Another solution is to use a shared handler like this
I have many events bound to elements in my view, though when I use stickit js to change values in my view by altering the model it doesn't trigger an onChange event.
Is there a way that I can trigger an onchange event for the current model:element after the setting the value in the model without having to write a handler for every binding? This would be for all form elements, input/select/textarea.
I want to avoid the following for each form element on the page:
bindings: {
'#foo': {
observe: 'foo',
afterUpdate: 'forceChange'
},
'#bar': {
observe: 'bar',
afterUpdate: 'forceChange'
},
...
},
forceChange: function(el) { jQuery(el).change() }
One possible hack (with version 0.6.3 only) would be to define a global handler which matches all elements:
Backbone.Stickit.addHandler({
selector: '*',
afterUpdate: function($el) {
$el.trigger('change');
}
});
Since handlers are mixed in with other matching handlers and bindings configurations in the order that they are defined, you couldn't use afterUpdate in any of your bindings without overwriting this global, all-matching handler since the bindings configurations are the last to be mixed in. You can read more about it here.
Ahhh, that comment clarifies matters. So, in Javascript when you change an input's value "manually" (whether through jQuery or through someElement.value =) the browser won't, as you noticed, fire a change event. Change events (and most other events for that matter) are only fired in response to user actions, not to Javascript.
Luckily, just as you can "manually" change a value, you can also "manually" trigger an event. In jQuery the syntax for that is:
$(yourElement).trigger('change');
If you need to control things like e.target you can read up on the jQuery trigger documentation for the details, but that's the basic idea.
You can even chain the value-changing and event-triggering together if you want:
$(yourElement).val('newValue').trigger('change');
I have little experience with ExtJS3 and now starting with version 4.
In my controller, I have this:
init: function ()
{
this.control({
"userlist":
{
selectionchange: function (view, selected, opts)
{
//get to grid??
}
}
});
}
How can I access the grid that this event happened on, without using id's?
I want to enable/disable buttons on the grid toolbar (tbar) if there are items selected, but I don't want to give anything id's (not the bar, not the individual buttons)
EDIT: the solution was to use the refs property in the controller:
refs:
[
{
ref: "list",
selector: "userlist"
}
],
selectionchange: this.activateTbButtons
activateTbButtons: function (selected, opts)
{
if (selected.selected.length == 1)
{
var tb = this.getList().query("toolbar");
}
}
Just found out that you can use the attribute view, and views under Ext.selection.Model.
This can be useful in cases when you let's say open multiple instances of your objects.
So, to access the grid in your example:
selectionchange: function (view, selected, opts) {
//get to grid??
var grid = view.view.ownerCt;
}
Having the same problem and found the previous answers missing some points. In short, I recommend:
selectionchange: function (selModel, selected, eOpts) {
var grid = selModel.view.ownerCt;
}
This was already proposed by Adezj although it referred to the selectionchange event that has the view as the first argument, and is not applicable to ExtJS 4.0.7+. (Don't think that selectionchange ever had the view as an argument?)
Note that this might not be officially supported by ExtJS since the view property of the selection model is not mentioned in the API docs at all.
Another approach is to use Ext.ComponentQuery.query(...) or defining refs in the controller, as proposed by Arun V, which is basically just a handy wrapper for Ext.ComponentQuery.query(). This works fine if you only have individual instances of the grid class but you need to take care in case you have multiple instances of the same grid class. Simply doing Ext.ComponentQuery.query('xtype-of-your-grid') will return all instances of your grid and you will have lots of fun finding out in which one the user has selected something.
So, in general, I would highly recommend to always work your way up from the component or object that fired the event to be sure you are in the right branch of the component hierarchy unless you are sure you will never have more than one instance of that class you write a controller for.
EDIT
I took a look at the docs for the selectionChange event:
selectionchange( Ext.selection.Model this, Ext.data.Model[] selected, Object eOpts )
The view is not being passed in to the selectionchange handler. An easy way to handle this is to either use Ext.getCmp() or use refs as seen in the docs for Ext.app.Controller:
http://docs.sencha.com/ext-js/4-0/#!/api/Ext.app.Controller
//get grid
var grid = selectionModel.view.ownerCt.ownerCt;