In a widget, I'm adding a refresh method and I need to cleanup everything before re-applying all the hooks. However, I'm not sure what are the consequences of calling this._hoverable(selector); multiple times on the same elements.
Looking inside jquery-ui-1.10.js, I see that the widget factory keeps a jQuery object of the elements, and it performs an add operation with the selector. While I assume it wouldn't add duplicate DOMelements, it's more the next operation : _on that makes me doubt.
Is it ok to call _hoverable and such multiple times on the same element?
No, you should not do that. Calling _hoverable() more than once on an element will register additional handlers on the mouseenter and mouseleave events.
If you absolutely have to call this method more than once, you will have to unbind these handlers beforehand:
this._off(element, "mouseenter mouseleave");
this._hoverable(element);
Note the events are namespaced under the hood, so the call to _off() above will only unbind the handlers registered through _on(), not additional handlers you may have registered yourself.
Related
I have a JS component (SigPlot) that I need to read click values from. I have instantiated SigPlot inside of a VerticalLayout, where I also instantiate a DIV to pass to the SigPlot constructor. I am not sure if this is a valid way, but it works.
Now I need to read CLICKS but I am having troubles finding correct way to do this. Can someone pass some words of wisdom?
In my constructor for my VIEW, it use addAttachListener to start my JS code using.
div.addAttachListener(e->{
e.getUI().getPage().executeJs("myInit($0)",div);
});
How can I register a click listener to this?
Regards
As long as it's just a regular DOM event listener, then something like this should work:
div.getElement().addEventListener("click", event -> Notification.show("Clicked"));
If you need to do something on a more granular level, then your might want to expose callbacks as #ClientCallable and then use executeJs to run some short JavaScript snippets to set up listeners that delegate to those methods.
I have build a plugin (pluginA) based on zeptojs and inside this plugin I fetch data using ajax and attach a list of
How do I bind an event to these anchors? I was going for something globally like and then use $('[data-key]').pluginB() and then inside pluginB() have something like
$(this).on('click', function (e) { e.preventDefault(); ... }); but I am not able to bind the click event to anchors created dynamically.
I tried adding $('a').on('click', ...) before I call pluginA() but it's not firing.
What I really would like would be to use the bind() trigger() approach in order to decouple the two plugins, but I am having trouble finding a good example.
Use the delegating form of on to bind all desired links in a particular area (in this example, the entire body):
$(body).on('click', 'a[data-key]', function(e) {e.preventDefault();...});
Now all links with data-key will trigger your function, regardless of whether or not they were present at the time you called on; subsequently-added links will automatically get the behavior, and removed links won't leak memory by holding dangling handler references.
I'm trying to maintain a widget that triggers events using one of these two lines of code:
this.element.trigger('change'); // or...
stop: function (event, ui) { that.element.change(); }
The word 'change' occurs only 4 times in the code, in one of the 2 forms above. However, I've got no idea what's going on here. There's no event handler in the change call, and there are no bind, delegate, on, or live calls, so something external is presumably setting this up. Can anyone fill me in? Are there any docs on this? Thanks.
Those two lines of code simply trigger a change event to this.element using two different allowed syntax.
Using .trigger():
this.element.trigger('change');
Or using a shorthand method .change():
that.element.change();
You can actually bind an event handler to the element represented by this.element to handle this event.
Without knowing your plugin, it is difficult to answer you precisely on what is this.element.
But take the example of the autocomplete plugin. In this one, this.element is actually the input field the autocomplete plugin is applied to. If the change event was triggered like supposedly done in your question, you could bind an event handler to the input like this:
$('#myinput')
.autocomplete()
.bind('change', function() { });
Now if this plugin relies on the jQuery UI Widget Factory, it is advisable to use the method _trigger() to trigger events instead of the jquery .trigger().
Using _trigger() will make sure to execute any callback defined in the plugin's option with a correct context and also trigger that event for this.element (like above). So you could have:
$('#myinput')
.somePlugin({
change: function(e, someData) {
// "this" here will be `this.element´
}
})
.bind('change', function() { ... });
The answer turned out to be simple - there was no event handler, there were no bind/etc calls, jQuery does nothing behind the scenes, so the trigger calls did nothing. I commented them out and the widget behaved exactly the same. Doh.
I have common code that I want in various events for our standard jqGrid configuration.
I use $.extend($.jgrid.defaults, { }); to set some code for the following:
loadError()
beforeRequest()
loadComplete()
gridComplete()
Now, when I define an instance of my grid, there is a potential that I would like to execute more code in any of these events.
My initial solution was to have global variables, e.g.: loadCompleteEx() and if they are defined, call them at the end of the default method calls. This was great if I only had one grid on the page, but I am trying to implement a solution that would work regardless of how many grids are on the page.
Is there some way to hook in and add a method to execute when any of these events are fired? I'm using jqGrid 4.1.2 and jQuery 1.6.
Thanks in advance for your help!
You can .bind() your own functions to events, so that your function executes with the event. You could use this to bind different events to each grid, or bind one function to every grid at once.
.bind() also allows binding to standard javascript events, custom events, or even undefined strings which you later call with .trigger().
It needs to be attached after a selector, which can select a specific grid or multiple grids in your case.
$('#Your-Grid-Selector').bind('eventToBind', functiontoBind() {
alert('Triggered eventToBind');
});
jQuery Documentation
Edit: This question may be a duplicate of this SO Question, which has a good solution you can use for this very issue.
In Nitrogen, the Erlang web framework, you wire actions like this:
wf:wire(send_message, #event { type=click, postback=send_message })
but if after that you run
wf:wire(send_message, #event { type=click, postback=send_message2 }),
then you get the action wired twice.
How do you unwire the previous action or all actions of an element?
Since events in nitrogen are bound using jquery's bind method. You can use unbind to unbind them. There isn't currently a nitrogen api to unbind an event but you could output the javascript code to unbind it yourself if you so wished.
see action_event.erl for an example of how the binding javascript is output. You can create a similar action/event that removes the binding.
I too was looking for an "unwire" and didn't find it. My work-around was to wf:replace() the element to which the event was wired, and wire the replacement element; I hope that javascript will eventually notice the former bind can never be called and then garbage collect it. I don't know how expensive such abandoned bindings are. My context was a lazy loading of the page, such that a button would initially show a stub, but when clicked would download arbitrarily large content, and henceforth toggle hide/show.
Beyond being nervous about the sophistication of the javascript garbage collection, I'm worried that this may be a bad pattern, and would love to hear others' experience. The only alternative that occurs to me would be to keep state (e.g. data) in the original element and pass that state back with the event message so that the same event handler would act on the "unloaded->loaded_show->loaded_hide->loaded_show" transitions. But I'd prefer not to be calling back to the server for a simple hide/show transition.