Trying to implement a add/remove sub-item entry; increment/decrement buttons add slots into the array and input fields are added/removed automatically:
<div *ngFor="let item of itemsInNewOrder; let i = index">
<input [(ngModel)]="itemsInNewOrder[i]" xtype="text" name="order" title="order" />
</div>
This is working functionally, but every time a letter is entered into the input, the element is deselected and must be clicked again to enter yet one more letter. How can I solve this?
http://blog.thoughtram.io/angular/2016/02/22/angular-2-change-detection-explained.html
The link above explains change detection in Angular 2. It also describes some other change detection strategies that you might find useful.
Basically since you did a 2 way binding [(ngModel)]="itemsInNewOrder[i]" to the itemsInNewOrder array, Angular is trying to be helpful and update the view for you.
Each keystroke updates your model (itemsInNewOrder)
Angular detects the update
Angular renders the view again with new form controls
Again, these are new form controls so the user hasn't focused one yet. This is why you have to click into the control after every entered character.
You can fix this by removing your 2 way binding and instead listening to the blur event for each input or implementing something described in the link above.
Blur event listening example:
<input (blur)="blurHandler(item,i)" type="text" name="order" title="order" />
Component
blurHandler(val:string,ndx:number) {
this.itemsInNewOrder[ndx] = val;
}
This might help too
Angular 2 change event - model changes
You can also wrap the values into objects. I don't know why you don't lose focus if you do it like this.
Component:
itemsInNewOrder = [{value: 'Soda'}, {value: 'Burger'}, {value: 'Fries'}];
template:
<div *ngFor="let item of itemsInNewOrder; let i = index">
<input
type="text"
name="order"
title="order"
[(ngModel)]="itemsInNewOrder[i].value"/>
</div>
The simplest answer to this was that I needed to learn and implement Angular 2's reactive forms library, which is part of Angular 2. Using this, I ran into none of difficulties I was experiencing.
Related
I currently have an accordion with a bunch of options in the form of checkboxes. The user can select the checkboxes as expected however, I want to already have some of those checkboxes checked depending on certain conditions. The issue is sometimes that is determined after the page has loaded. Below are simplified examples to demonstrate my code (my code is for work and would not be able to share due to confidentiality issues).
My HTML looks like this:
<div class="row">
<div "ngFor="let value of filteredPeople" >
<div>
<input type="checkbox" (click)="selectPeople(value)" [checked]="checkedPeople.get(value)">
{{ value }}
</div>
</div>
</div
My Javascript:
public checkPeople() {
this.selectedPeople.forEach(element => {
this.checkedPeople.set(element, true);
});
}
To explain some variables and methods:
Variables:
filterPeople - a string array of all possible people
checkedPeople - a map with a KVP of string (the people) and boolean (whether or not their checkbox is checked)
selectedPeople - a string array of people whose checkboxes I want already checked
Methods:
selectPeople - checks the corresponding checkbox when user clicks on it
checkPeople - a method called when I want the specific checkboxes checked (these specific checkboxes change based on other factors so I cannot hard code it)
For some reason my checkPeople method does not seem to select the expected checkboxes, I am not sure why but I have a feeling it is to do with the fact that I have used "[checked]" in the HTML and that it should be something else. Can someone clarify the issue for me and help me identify a fix? (Note: as the title suggests, I am using Angular)
Edit:
I have just debugged my code and added breakpoints, the checkedPeople map has the correct mapping of people to true for each of the elements in selectedPeople which shows that the checkPeople method is working as expected. Therefore the issue must be with the [checked] attribute if I'm not mistaken. I cannot see why it wouldn't work though.
You should use [ngModel]="checkedPeople.get(value)"
instead of [checked]="checkedPeople.get(value)"
to initialize the checkbox and
(change)="checkUncheckPeople(value, $event)"
to update the value when you check or uncheck it, where
checkUncheckPeople(value, e) {
this.checkedPeople.set(value, e.target.value);
}
So, in conclusion, your HTML input element will be:
<input
type="checkbox"
[ngModel]="checkedPeople.get(value)"
(change)="checkUncheckPeople(value, $event)"
/>
If you choose to use an object instead of a map then you can also directly use
[(ngModel)]="checkedPeople[value]"
to two-way bind the variable
I am attempting to use a checkbox in Angular in order to toggle the contents of an array. I am using property booleans to determine if 3 different boxes are checked and adjust the contents of the array accordingly. The array defaults to containing all 3 subarrays via declaring this.allNouns in ngOnInit(). When I click the first checkbox, I can see in the console that it is running the associated onchange function and setting the associated boolean to its opposite, but the interpolated string in the view does not change. When I click it again, it will change the view but now everything is one step behind. Also when it hits the console logs, it appears to load the prior length and not the length of the newly established this.allNouns. Below are the html and ts snippets associated with it. This is the first of the three checkboxes, but I plan to apply it to all when smoothed out.
TS
preloadedNouns: Boolean = true;
toggleData() {
if(this.preloadedNouns==false){
this.allNouns=this.nouns.concat(this.onlyUserNouns);
console.log('hitting first condition in toggledata', this.allNouns.length);
}
else {
this.allNouns=this.nouns.concat(this.stockNouns).concat(this.onlyUserNouns);
console.log('hitting second condition in toggledata', this.allNouns.length);
}
}
HTML
<div name="allNouns" [(ngModel)]="allNouns" [ngModelOptions]="{standalone: true}" ngDefaultControl>{{allNouns.length}}</div>
<div class="toggleDiv">
<label>Preloaded Nouns</label>
<input id="preloadedNounsCheck"
type="checkbox"
[checked]="preloadedNouns"
(change)="toggleData(); preloadedNouns = !preloadedNouns">
</div>
i don't clear about your nouns logic.
<div class="toggleDiv">
<label>Preloaded Nouns</label>
<input id="preloadedNounsCheck"
type="checkbox"
[checked]="preloadedNouns"
(change)="preloadedNouns = !preloadedNouns;toggleData()">
</div>
but i hope based on my understanding above code will help to you.
just reorder the function call in (change).
I have been working all day to try and get the selected values on one set of checkboxes on my Django form and copy the selected ones only to an identical checkbox on my form. If a user clicks on a checkbox in form.author defined below, I want the same identical checkbox to automatically be checked on form.favorite_author defined below.
I've tried a JQuery approach as documented here...Copy Selected Checkbox Value From One Checkbox To Another Immediately Using JQUERY but no luck so far. I've recently begun exploring an avenue with the Modelmultiplechoicefield and the checkboxselectmultiple parameters within the form itself. From what I can tell, when I am using JQuery and trying to check a box on the form, the value is coming back as undefined which is most likely why it is not propagating the checkbox selection to the other checkbox.
Here is my form....
class ManagerUpdateNewAssociateForm(forms.ModelForm):
class Meta:
model = Library
self.fields['author'] = forms.ModelMultipleChoiceField(
widget=forms.CheckboxSelectMultiple(),
queryset=Books.objects.all()
self.fields['favorite_author'] = forms.ModelMultipleChoiceField(
widget=forms.CheckboxSelectMultiple(),
queryset=Books.objects.all()
My HTML...
<div class="spacer83">
{{ form.author }}
</div>
<div class="spacer83">
{{ form.favorite_author }}
</div>
When I tried to trace JQuery, it told me the checkbox selections are undefined. I did read a bit about how Modelmultiplechoicefield, since it uses a queryset it doesn't show the selections, but I can't figure out how to get it to.
Thanks in advance for any thoughts.
In combination with the other issue included in this one, I went back to the JQuery route and explored further. From what I can tell, I was not able to use the class for the input because of the way the HTML for Django forms is generated in this use case. I ultimately was able to leverage the input name and then used the code below to interrogate the checkboxes accordingly:
$(document).ready(function() {
$("[name=author]").change(function() {
let selectedValA = $(this).val();
let isAChecked = $(this).prop("checked");
$(`[name=favorite_author][value="${selectedValA}"]`).prop("checked", isAChecked);
});
});
});
I'm trying to use jQuery geocomplete along with Vue.js to populate a form with geo data.
My code contains this form:
<form>
<label for="get-offer-location">location: </label><input id="get-offer-location" v-model="newoffer.location" type="text"/>
<div style="visibility:hidden">
<input name="lat" type="text" value=""/>
<input name="lng" type="text" value=""/>
</div>
</form>
After I click on a suggested location from the get-offer-location input, it looks like the field is filled out -- but then when I start typing in another field, the location input field reverts to just the letters I typed in for the location search. Try it out here by clicking "post", then "news" or "offers":
https://jsfiddle.net/dvdgdnjsph/157w6tk8/
Can anyone tell me what's wrong?
The problem you are having is that v-model binds on input, since the geolocation dropdown is a plugin that changes the value programatically the input event is not fired, so v-model is not updated. As a case, try typing a space after selecting a location, you will see that it sticks.
Fortunately, v-model is nothing more than syntactic sugar for v-on:input, so you can use v-on to fire your event instead. Considering that you are going to need to unfocus to get out of the box, the blur event is likely to be your best option, so you can simply do:
v-on:blur="newarticle.location = $event.target.value"
Unfortunately, JSFiddle won't let me save or update your Fiddle, but I did get it working with the code above.
For completeness, in case you want to use this behavior extensively, and because the Vue docs are fairly limited in this regard, you may write a custom directive to encapsulate the code:
Vue.directive('model-blur', {
bind: function(el, binding, vnode) {
el.addEventListener('blur', function() {
vnode.context[binding.expression] = el.value;
});
}
});
Then you can use like so:
<input v-model-blur="myVar" />
Here's the JSFiddle: https://jsfiddle.net/4vp6Lvmc/
Can't tell for sure. But it looks like jQuery plugin just changes input#get-article-location value, but not the Vue model. So when you trigger model update (e.g. editing headline) it overwrites complete location with whatever you typed in.
I have something like this for catch the geocomplete event and try to set the vueJS value :
$("#get-article-location")
.geocomplete({details: ".details"})
.bind("geocode:result", function (event, result) {
vm.newoffer.location = result.formatted_address;
console.log('done');
});
But something still appears wrong, I think you should really change the name of your vueJS instance (var vm) it may be use by another script and make troubles.
This is because v-model, as two-way binding, on the receiving-user-input way, listens to the input event on the input element, while js plugins (like jquery-geocomplete) obviously set input values via js, which leads to the view model's data not changing as we discussed in other answers.
To fix this, just listen to the geocode:result event of the plugin and manually change the data with code (there seems to be something wrong with jsfiddle so I'm posting it here):
var vueVM = this;
$("#get-offer-location").geocomplete({ details: ".details" });
$("#get-article-location")
.geocomplete({ details: ".details" })
/***** highlight start *****/
.bind("geocode:result", function(event, result){
console.log(result);
//tried result.something but couldn't find the the same thing as `this.value`
vueVM.newarticle.location = this.value;
});
/***** highlight end *****/
extra knowledge: the mechanism of v-model stated above is usually used in making reusable components, by receiving a value prop from the parent, and emitting an input event with the user-input value when detecting change on the input element in the component. And then we can use <my-component v-model='parentData'></my-component> as the child behaves exactly like a simple input element from the parent's perspective. example
Working with a set of column components with id input in my template:
<div class="panel-body" *ngIf="columns">
<div class="col-md-4">
<column [id]=columns[current_left_column].Id></column>
</div>
<div class="col-md-4">
<column [id]=columns[current_middle_column].Id></column>
</div>
<div class="col-md-4">
<column [id]=columns[current_right_column].Id></column>
</div>
</div>
I have buttons that increment and decrement the columns by changing the values of current_left_column, current_middle_column, and current_right_column. When I click those buttons I log the values of the three column id's and they're representative of where they should be however the template doesn't reload.
I did attempt to use ApplicationRef.tick() to trigger change detection, but the fact that it didn't change makes me think it's a binding issue, but I'm thus far unable to find anything that matches my case as 2-way binding seems to necessitate a more traditional input element and it currently is one way bound.
I think you need to change the name of the input. I have seen it several times that it collides with the id property every HTML element has.
I really appreciate the comments and info given, it helped me get a better handle on what I was actually trying to do.
I ended up taking an example from a different answer and using ngModel with an input to show the individual column id's. Then since I could prove my id's were switching but it wasn't updating even with the tick() I realized I was working on one component level too high and had to be initiating the change from the Column level. So I took the ngOnInit method that populates the columns with data and put it in a ngOnChanges() method, cleared the OnInit() because it was doubling up, and it started moving fine.
Then I had to deal with the information from the columns being added on top of the prior column, but that was relatively minor.
ngOnChanges(){
this._columnService.GetSingleColumn(this.id).subscribe(column => { this.columnData = column; });
this._cardService.GetCardsByColumnId(this.id).subscribe(cards => { this._cardColumnService.LoadCards(cards); console.log(this.cards); });
if (this.columnData == undefined) {
this.LoadDummyData();
}
}