This is a follow up to this question: Access a DOM element in Aurelia
Is there a hook in the Screen Activation Lifecycle which allows me to run code after ref bindings have been set up? Currently it seems like there is a period of time after the activate hook is called when the ref bindings are not set up yet and then at some point they get activated. I tested this by adding a <div ref="myDiv"></div> to near the bottom of welcome.html in a cloned version of the latest (v0.13.0) skeleton-navigation repo and testing the existence of the reference in the view-model like this:
export class Welcome{
heading = 'Welcome to the Aurelia Navigation App!';
firstName = 'John';
lastName = 'Doe';
testMyDiv() {
console.log("Getting my div")
console.log(this.myDiv)
}
get fullName(){
this.testMyDiv()
return `${this.firstName} ${this.lastName}`;
}
welcome(){
alert(`Welcome, ${this.fullName}!`);
}
}
A snippet of the bottom of the template...
<button type="submit" class="btn btn-default">Submit</button>
</form>
<div ref="myDiv"></div>
</section>
</template>
This is a snapshot of what I see in the console...
welcome.js:10 Getting my div
welcome.js:11 undefined
welcome.js:10 Getting my div
welcome.js:11 undefined
welcome.js:10 Getting my div
welcome.js:11 <div ref="myDiv" class="au-target"></div>
welcome.js:10 Getting my div
welcome.js:11 <div ref="myDiv" class="au-target"></div>
(continues)
The print outs like this goes on indefinitely. You can see that fullName() is being called regularly to update the screen if the name changes (I assume this is the dirty checking)... but you can see that at the beginning there is a period when the referenced div is NOT valid as a property of the view-model, and then it IS valid. Can someone explain this? Is there a way to hook into the view-model after the ref becomes valid?
In general, bindings are processed and available after the bind callback. However, in this case since you need to access the DOM element, you will need the ViewModel to be bound and attached to the view, so use the attached callback.
class ViewModel {
bind() {
this.refItem == undefined; // true
}
attached() {
this.refItem == undefined; // false
}
}
As you noted in the comments, more information on the activator callbacks is available here: http://aurelia.io/docs.html#extending-html
Related
I have a problem with a vue component that handles model changes.
In the parent component I have something like this:
<div v-for="role in roles">
Start date: {{ role.start_date) }}
<button #click="handleSelectRoleToEdit($event, role)" id="start_date"</button>
</div>
<edit-role
:role="selectedRole"
:editField="editField"
ref="ToEditRole"
>
</edit-role>
where handleSelectRoleToEdit is
handleSelectRoleToEdit(event, role) {
this.selectedRole = role;
this.$refs.ToEditRole.editRoleModal()
this.editField = event.currentTarget.id
}
This piece of code should take the current item and pass it to the child component <edit-role>. Inside the child component there is
props: [
"role",
"editField"
]
...
editRoleModal() {
this.modal_edit_role = new Modal(document.getElementById('edit_roleModal'), {})
this.modal_edit_role.show()
console.log(this.role)
}
The modal is successfully created and opened, but console.log(this.role) returns Proxy {}.
If I edit the fields (so I call another function), everything is fine, because this.role becomes available.
However I need this.role to be available as soon as the modal is created.
How can I solve this problem?
Any help is greatly appreciated
I don't know if this suits your needs, but instead of using $refs you could set a watcher for the prop role in the child component. This ensures that the function is executed when the data is available.
I am struggling to understand why an emitted event on a child component is not getting picked up by the parent.
The event is getting emitted from the child component - I can see it in the toolbar along with the correct values. The method that is tied to the event is not getting called on the parent component. ChildComponent.vue is a form that is imported into ParentComponent.vue.
Here is what I have (that's working but not).
ParentComponent.vue
<child-component/>
<div v-show="this.label === 'acme'" #label:name="handleLabelName">
<h3>Hello World</h3>
...
</div>
...
methods: {
handleLabelName(name) {
console.log('handleManualType called'); // never getting here
console.log('name: ', name); // never getting here
}
},
ChildComponent.vue
...
<button data-label="acme" #click="handleClick($event)">Click Me</button>
...
methods: {
handleClick(event) {
const label = event.target.dataset.label;
this.$emit('label:name', label); // acme
},
The event is getting broadcast, but handleLabelName is never getting called. I've read through this great article many times and I believe I'm following it correctly. Is there something I am doing wrong to make handleLabelName never get called? I've also tried wrapping everything in a div like so:
<div #label:name="handleLabelName">
<div v-show="this.label === 'acme'">
<h3>Hello World</h3>
...
</div>
</div>
And still the same result. handleLabelName never gets called. I've also tried changing the event name/method to simple things like, foo and still no difference.
Thank you for any suggestions!
You are listening for events on a div instead of listening to your child component. You must put your listener on the DOM element that sends the event. Try something like this :
<child-component #my-event-name="handleLabelName"/>
Another point is that you might prefer using kebab case to name your custom events. It might be a problem to name your event with this character ":" (see https://v2.vuejs.org/v2/guide/components-custom-events.html)
I'm working on a Vue.js project, and when I click on an element, I'm using the Vue transition tag to fade it out. The problem is that as the element is in the process of being faded out, it is still clickable, which in my application can cause issues.
My question is: how can I make an element unclickable during a transition, so that users don't click it multiple times before the transition finishes?
I've already tried applying a css class with point-events: none; to the element right when the transition starts, but it didn't stop clicks during transition.
Example:
<transition name="fade">
<div v-if="shouldShow" #click="doSomeAction">Example text</div>
</transition>
(where doSomeAction sets shouldShow to false).
Vue has event modifiers that might help with that. The specific one which might be helpful to you is #click.once. If you add this to the click event the user will only be able to click it once. Documentation for it is here.
If you are using Vue.js 2.6+ you can do it with ease. In this minor realse Dynamic directive arguments was added, so you can conditionally bind desired event name, or in you case disable it (passing null).
Dynamic argument values are expected to be strings. However, it would
be convenient if we allow null as a special value that explicitly
indicates that the binding should be removed. Any other non-string
values are likely mistakes and will trigger a warning.
Reference.
// using computed property
<transition name="fade">
<div v-if="shouldShow" #[event]="doSomeAction">Example text</div>
</transition>
export default {
data() {
return {
shouldShow: true
}
},
computed: {
event() {
return this.shouldShow ? "click" : null;
}
}
}
// using object
<transition name="fade">
<div v-if="shouldShow" v-on="{ [shouldShow ? 'click' : null]: doSomeAction }">Example text</div>
</transition>
Update
If you also need to ensure that users can immediately click "through" the element that is being faded out to items behind it, you can add a class with pointer-events: none; to the element, and then do this:
this.$nextTick(() => {
this.shouldShow = false;
});
This will make sure the fade doesn't happen until the class has been added. this.$nextTick is a Vue function that waits for the dom to update (which in this case is adding the pointer-events class) before running a callback: https://v2.vuejs.org/v2/api/#Vue-nextTick
Note that pointer-events: none; doesn't work on some very old browsers (IE < 10)
i make modal popup components myPopup.vue for global.
and import that in App.vue and main.js
i use this for global, define some object Vue.prototype
make about popup method in Vue.prototype
like, "show" or "hide", any other.
but i think this is maybe anti pattern..
i want to find more best practice.
in App.vue
<div id="app>
<my-popup-component></my-popup-conponent>
<content></content>
</div>
main.js
...
Vue.prototype.$bus = new Vue(); // global event bus
Vue.prototype.$popup = {
show(params) {
Vue.prototype.$bus.$emit('showPopup', params);
},
hide() {
Vue.prototype.$bus.$emit('hidePopup');
}
}
Vue.component('my-popup-component', { ... });
...
myPopup.vue
....
export default {
...
created() {
this.$bus.$on('showPopup', this.myShow);
this.$bus.$on('hidePopup', this.myHide);
}
...
need-popup-component.vue
methods: {
showPopup() {
this.$popup.show({
title: 'title',
content: 'content',
callback: this.okcallback
});
}
}
It seems to be works well, but i don't know is this correct.
Is there any other way?
I was very surprised while reading your solution, but if you feel it simple and working, why not?
I would do this:
Add a boolean property in the state (or any data needed for showing popup), reflecting the display of the popup
use mapState in App.vue to bring the reactive boolean in the component
use v-if or show in App.vue template, on the popup declaration
create a 'showPopup' mutation that take a boolean and update the state accordingly
call the mutation from anywhere, anytime I needed to show/hide the popup
That will follow the vue pattern. Anything in state, ui components reflect the state, mutations mutates the state.
Your solution works, ok, but it doesn't follow vue framework, for exemple vue debug tools will be useless in your case. I consider better to have the minimum of number of patterns in one app, for maintenance, giving it to other people and so on.
You somehow try to create global component, which you might want to consume in your different projects.
Here is how I think I would do this -
How do I reuse the modal dialog, instead of creating 3 separate dialogs
Make a separate modal component, let say - commonModal.vue.
Now in your commonModal.vue, accept single prop, let say data: {}.
Now in the html section of commonModal
<div class="modal">
<!-- Use your received data here which get received from parent -->
<your modal code />
</div>
Now import the commonModal to the consuming/parent component. Create data property in the parent component, let say - isVisible: false and a computed property for the data you want to show in modal let say modalContent.
Now use it like this
<main class="foo">
<commonModal v-show="isVisible" :data="data" />
<!-- Your further code -->
</main>
The above will help you re-use modal and you just need to send the data from parent component.
How do I know which modal dialog has been triggered?
Just verify isVisible property to check if modal is open or not. If isVisible = false then your modal is not visible and vice-versa
How my global dialog component will inform it's parent component about its current state
Now, You might think how will you close your modal and let the parent component know about it.
On click of button trigger closeModal for that
Create a method - closeModal and inside commonModal component and emit an event.
closeModal() {
this.$emit('close-modal')
}
Now this will emit a custom event which can be listen by the consuming component.
So in you parent component just use this custom event like following and close your modal
<main class="foo">
<commonModal v-show="isVisible" :data="data" #close- modal="isVisible = false"/>
<!-- Your further code -->
</main>
I am using the Durandal Starter Template for mvc4. I have set the following simple View:
<section>
<h2 data-bind="html: displayName"></h2>
<h3 data-bind="html: posts"></h3>
<button data-bind="click: getrss">Get Posts</button>
<div id="rsstestid" ></div>
</section>
and ViewModel:
define(function (require) {
var http = require('durandal/http'),
app = require('durandal/app');
return {
displayName: 'This is my RssTest',
posts: ko.observable(),
activate: function () {
return;
},
getrss: function () {
$('#rsstestid').rssfeed('http://feeds.reuters.com/reuters/oddlyEnoughNews');
return;
}
};
});
As you can see, it is simply using the zRssReader plugin to load posts into a div when the 'Get Posts' button is clicked. Everything works fine, the display name is populated and the posts show up as expected.
Where I am having trouble is when I try to eliminate the button and try to load the posts at creation time. If I place the plugin call in the activate function, I get no results. I assume this is because the view is not fully loaded, so the element doesn't exist. I have two questions:
How do I delay the execution of the plugin call until the view is fully composed?
Even better, how do I load the plugin result into an the posts observable rather than using the query selector? I have tried many combinations but no luck
Thanks for your help.
EDIT** the below answer is for durandal 1.2. In durandal 2.0 viewAttached has changed to attached
Copy pasted directly from durandaljs.com
"Whenever Durandal composes, it also checks your model for a function called viewAttached. If it is present, it will call the function and pass the bound view as a parameter. This allows a controller or presenter to have direct access to the dom sub-tree to which it is bound at a point in time after it is injected into its parent.
Note: If you have set cacheViews:true then viewAttached will only be called the first time the view is shown, on the initial bind, since technically the view is only attached once. If you wish to override this behavior, then set alwaysAttachView:true on your composition binding."
--quoted from the site
There are many ways you can do it but here is just 1 quick and dirty way:
<section>
<h2 data-bind="html: displayName"></h2>
<h3 data-bind="html: posts"></h3>
<button data-bind="click: getRss">Get Posts</button>
<div id="rsstestid"></div>
</section>
and the code:
define(function (require) {
var http = require('durandal/http'),
app = require('durandal/app');
var $rsstest;
return {
displayName: 'This is my RssTest',
posts: ko.observable(),
viewAttached: function(view) {
$rssTest = $(view).find('#rsstestid');
},
getRss: function() {
$rssTest.rssfeed('http://feeds.reuters.com/reuters/oddlyEnoughNews');
}
};
});
In general, I think it's wise to refrain from directly touching UI elements from within your view model.
A good approach is to create a custom KO binding that can render the rss feed. That way, you're guaranteed that the view is in place when the binding executes. You probably want to have the feed url exposed as a property on your view model, then the custom binding can read that when it is being updated.
Custom bindings are pretty simple - if I can do it, then it must be :)
Here's a link to the KnockOut custom bindings quickstart: http://knockoutjs.com/documentation/custom-bindings.html
I too am having the same problem, I'm trying to set a css property directly on an element after the durandal view model and view are bound together. I too assume that it's not working because the view is not fully composed at the point I am setting the value.
Best I have come up with is using the viewAttached lifecycle event in durandal, which I think is the last event in the loading cycle of a durandal viewmodel, and then using setTimeout to delay the setting of the property still further.
It's a pretty rubbish workaround but it's working for now.
var viewAttached = function (view) {
var _this = this;
var picker = new jscolor.color($(view).children('.cp')[0], {
onImmediateChange: function() {
_updateCss.call(_this, this.toString());
}
});
picker.fromString(this.color());
setTimeout(function() {
_updateCss.call(_this, _this.color());
}, 1000);
};
var activate = function (data) {
system.log('activated: ' + this.selectors + ' ' + this.color());
};
var deactivate = function (isClose) {
system.log('deactivated, close:' + isClose);
};
return {
viewAttached: viewAttached,
deactivate: deactivate,
activate: activate,
color: this.color
};
I was having a similar issue with timing. On an initial page load, where a partial view was being loaded on the page I could call the viewAttached function and use jQuery to bind some elements within the partial view. The timing worked as expected
However, if I navigated to a new page, and then back to the initial page, the same viewAttached + jQuery method failed to find the elements on the page... they had not yet been attached to the dom.
As best as I have been able to determine (so far) this is related to the transition effects in the entrance.js file. I was using the default transition which causes an object to fade out and a new object to fade in. By eliminating the fadeOutTransition (setting it to zero in entrance.js) I was able to get the viewAttached function to actually be in sync with the partial views attachment.
Best guess is that while the first object is fading out, the incoming object has not yet been attached to the dom but the viewAttached method is triggered anyway.