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.
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'm looking for a way to cancel the resolve of a Angular-UI Bootstrap modal and stop it from opening. The dismissAll method is not working because the modal instance is added to the modal stack only after the resolve has completed.
I have a website where modals open and close on route change. If dismissAll is called during route change to close any old modals it won't affect modals that are still resolving. So you come to the new route but the old modal still pops up after its resolve has completed.
As things stand right now, there is no way to cancel ES6 and $q promises. you can refer to this question for more info.
tl;dr Bluebird allows promise cancellation
If you really need it you can add bluebird to angular.
If you still want to use plain ol' $q, here's what I would have done
Pass the modal the current state (if using ui-router) or route (if using angular router).
When you need to render the modal template compare the current state to the provided state.
If they are not equal discard the modal
The modalInstance object exposes a rendered promise that will run when the modal finished rendering, you can place $uibModalStack.dismissAll(); inside.
Example:
modalInstance.rendered.then(function (currentState) {
if (currentState !== $state.current) {
$uibModalStack.dismissAll();
}
}, function () {
$log.info('Modal dismissed at: ' + new Date());
});
Of course you can defer your loading after rendering the modal and avoid this mess altogether.
This is by far the simplest way to make sure modals never stick around, and it works for apps with simple modal use. I’ve seen this working for years at several places and reliably. Essentially, you register a state change listener in your router and whenever there’s a state change you make sure to dismiss all open modals, whatever those might be. Again, this might seem harsh, but in some apps this works like a charm, and is better than nothing.
A simple example, using UI Router’s $transition service and Angular UI Bootstrap’s $uibModalStack, this can be as simple as:
$transitions.onFinish({}, function(transition) {
$uibModalStack.dismissAll();
});
And of course, if needed, you can only perform this for transitions that match a specific criteria.
Source: https://www.codelord.net/2017/12/11/reliably-managing-modals-in-angularjs/
If I write the following Dart code, how do I know which click handler happens first?
main() {
var button = new ButtonElement();
var stream = button.onClick.asBroadcastStream();
stream.listen(clickHandler1);
stream.listen(clickHandler2);
}
Let's say I'm in other code that doesn't know anything about the first two click handlers, but I register another one.
Can I know that the stream has two listeners?
Can I pause or cancel all other subscribers?
If I write button.onClick.asBroadcastStream() again elsewhere, does it point to the same stream as was used in main?
Can I say in one of the handlers to not pass event on to the other broadcast listener? Is that a consumer?
Let's say I'm in other code that doesn't know anything about the first
two click handlers, but I register another one.
Can I know that the stream has two listeners?
No, you can't. You could extend the stream class or wrap it and provide this functionality yourself, but it does not feel like a good design choice, because I don't think a listener should know about other listeners. What are you trying to do exactly? Perhaps there's a better way than letting listeners know about each other.
Can I pause or cancel all other subscribers?
You can cancel/pause/resume only the subscriber you are dealing with. Again, you probably shouldn't touch other listeners, but I guess you could wrap/extend the Stream class to have this behavior.
If I write button.onClick.asBroadcastStream() again elsewhere, does it point to the same stream as was used in main?
No, at least not at the current version of SDK. So, unfortunately, you need to store a reference to this broadcast stream somewhere, and refer to it, because calling asBroadcastStream() multiple times will not yield in the result you might expect. (Note: at least based on quick testing: http://d.pr/i/Ip0K although the documentation seems to indicate different, I have yet to test a bit more when I find the time).
Can I say in one of the handlers to not pass event on to the other broadcast listener?
Well, there's stopPropagation() in the HTML land which means that the event won't propagate to other elements, but it's probably not what you were looking for.
For being able to stop an event firing in other listeners, there needs to be an order of which the listeners are getting called. I believe the order is the order of registration of those listeners. From the design perspective, I don't think it would be a good idea to allow a listener to cancel/pause others.
Event propagation in HTML makes sense since it's about hierarchy, but here we don't have that (and even in case of events in HTML there can be multiple listeners for the single element).
There's no way to assign weight to listeners or define the order of importance, therefore it's not surprising that there isn't a way to stop the event.
Instead of letting listeners know about each other and manipulate each other, maybe you should try to think of another way to approach your problem (whatever that is).
Is that a consumer?
The StreamConsumer is just a class that you can implement if you want to allow other streams to be piped into your class.
Can I know that the stream has two listeners?
No, you have a ´Stream´ that wraps the DOM event handling. There is no such functionality.
Can I pause or cancel all other subscribers?
Look at Event.stopPropagation() and Event.stopImmediatePropagation(), and possibly Event.preventDefault().
If I write button.onClick.asBroadcastStream() again elsewhere, does it point to the same stream as was used in main?
[Updated] No, the current implementation doesn't gives you the same Stream back since the onClick getter returns a new stream every time it is invoked. However, the returned stream is already a broadcast stream so you shouldn't invoke asBroadcastStream() on it. If you do you will hower just get a reference to the same object back.
Stream<T> asBroadcastStream() => this;
Can I say in one of the handlers to not pass event on to the other broadcast listener? Is that a consumer?
Again, take a look at Event.stopPropagation() and Event.stopImmediatePropagation(), and possibly Event.preventDefault().
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 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.