Can't set focus on an input box programmatically in Angular - html

I'm trying to follow a suggestion and have set a marker on the input control in my component like this.
<span (click)="onEditClick()"
[class.hidden]="editing">{{value}}</span>
<input #input
value="{{value}}"
[class.hidden]="!editing">
I noticed that clicking the span hides it and presents the input but an additional click is required to make the input control actually focused for editing. I tried to focusify it as follows.
#ViewChild("input") input: ElementRef;
onEditClick() {
this.editing = true;
this.input.nativeElement.focus();
}
It doesn't work, so I verified that the native element is set and corresponds to what I expect. It did. And since there are no errors in the console, I'm a bit stuck not knowing how to diagnose it further.
I suspect that I'm missing something rather basic that can easily be inferred from the provided description.

The problem is that the input element is still hidden when you try to set focus on it. To make sure that the input element has become visible after setting the editing property, force change detection by calling ChangeDetectorRef.detectChanges():
onEditClick() {
this.editing = true;
this.changeDetectorRef.detectChanges();
this.input.nativeElement.focus();
}
See this stackblitz for a demo.

Related

How to fix Angular bug requiring user to click a separate element before choosing a second mat chip

Here is the link for an example of the issue I will attempt to describe. In the chips autocomplete example, click the text box to select a new fruit.
Now, before clicking anywhere else, click again on the text box as you did before.
This should result in no options showing up. The issue here is that the user must either begin keying in a new selection or first click another element in the window before matchip will show the options to choose from. I am wondering if there is a way to fix this issue. I would like a user to be able to choose a selection from the list and then immediately click the text box as they had before and make a new selection.
I'm using mat-chip-list inside an outer *ngFor iterating over a FormArray.
Here is what I'have done. It's pretty efficient :
<input
#validatorInput
#operationTrigger="matAutocompleteTrigger"
[formControl]="contactCtrl"
[matAutocomplete]="auto"
[matChipInputFor]="chipList"
(blur)="contactCtrl.setValue(''); validatorInput.value='';"
(click)="contactCtrl.setValue(''); validatorInput.value=''; operationTrigger.openPanel()">
The trick is
Always clear your html input and your (shared) formControl with an empty and not null value each time the blur and click events occur.
Do NOT do this 'clear' on the input focus event. (Because when you delete the last chip, the input is auto-focus and you will have the famous Expression has changed after it was checked.
Call operationTrigger.openPanel(); when the user click on the input
Setting contactCtrl.setValue(''); allows your autocomplete panel to be automatically opened when you call operationTrigger.openPanel()
Setting validatorInput.value=''; is just a way to properly sync your formControl with the html input to ensure a good UX/UI behavior.
Inside my formArray, the formControl is the same for all the inputs but it does not matter since the user can only manipulate one input at a given time
Since you didn't post your code and you mention the example on the material site I'm going to do it as a fork of the stackblitz example they have on their site.
But this will allow you to open the autocomplete panel again despite having had the cursor there and choosing an option previously.
// Using MatAutocompleteTrigger will give you access to the API that will allow you to
// to open the panel or keep it open
...
#ViewChild(MatAutocompleteTrigger, {static: false}) trigger: MatAutocompleteTrigger;
...
ngAfterViewInit() {
fromEvent(this.fruitInput.nativeElement, 'click')
.pipe(
tap(() => {
this.trigger.openPanel()
})
).subscribe()
}
Link to the full stackblitz:
https://stackblitz.com/edit/angular-sb38ig

Angular2: undefined errors when trying to set focus to an input field using #ViewChild annotation

I have a input field which I set focus to when my view loads in the following way:
ngAfterViewInit() {
this.focusInput.nativeElement.focus();
}
this works fine from within the ngAfterViewInit() function but when I try to do it in another part of my view when a button is clicked I get an exception saying that focusInput is undefined. After reading up a bit it seems like ngIf could be the cause of this as the part of the view that contains the input field #focusInput gets shown or hidden using ngIf. Is there any way I can check using ngOnChanges() or anything else whether the #focusInput input field is currently shown and if it is set focus to it?
It happens when you have ngIf or ngFor directives inside your template and your input can not be linked to focusInput property you added inside your class. Instead use this code:
<input type="text" #myInput />
{{ myInput.focus() }}
Just add {{ myInput.focus() }} right after input inside template
The simplest solution turned out to be writing a custom focus attribute directive. This helped a lot:
How to move focus on form elements the Angular way
I know its very late to answer your question. If you want focus after any click or view change so for this you need to call change detector.
You can call change detection after your view change or a click by calling detectchanges().
`constructor(private detRef:ChangeDetectorRef) {}
#ViewChild('name_input') input: ElementRef;
private buttonClick(): void {
this.detRef.detectChanges();
this.input.nativeElement.focus();
}`
Hope this will helpful.

Why is a custom angular directive not disabled with ng-disabled set to true

I have been playing around with ngAria and ngDisabled in AngularJS using the example given here .I modified the custom-checkbox directive in the example to set ng-disabled= true in the controller , that further sets aria-disabled=true as seen in the plunker output here.
<some-checkbox role="checkbox" ng-model="checked" ng-class="{active: checked}" ng-disabled="isDisabled" ng-click="toggleCheckbox()" aria-label="Custom Checkbox" show-attrs>
var app = angular.module('ngAria_ngModelExample', ['ngAria'])
.controller('formsController', function($scope){
$scope.checked = false;
$scope.isDisabled=true;
$scope.toggleCheckbox = function(){
$scope.checked = !$scope.checked;
}
})...
But with ng-disabled=true and aria-disabled=true this does not disable the "Custom Checkbox" as seen in the plunker output.
As per the documentation here and several examples on stackoverflow, the "disabled" attribute works only for buttons, input and text area. For custom directives (like the one above), ngDisabled is the way to go. But it does not seem to work for the above example. Any help here is appreciated.
The disabled attribute is only valid for certain elements such as button, input and textarea
ngDisabled adds or removes the disabled attribute to your element. I suggest you watch the disabled expression in your custom directive, and add / remove a class to disable your component.
If you're creating your own component that you want to have support for ng-disabled, then you can add this inside $onInit after injecting $attrs and $parse:
// Watch ng-disabled
this.$scope.$watch(
() => {
let value = this.$attrs.ngDisabled;
// Evaluate ng-disabled expression on parent scope
let evaluated = this.$scope.$parent.$eval(value);
return evaluated;
},
(disabled) => {
this.disabled = disabled;
}
);
As with all ARIA controls, the browser does not give you any "behavior" for free. What the addition of roles like "button" does is it instructs the browser/screen-reader what to do with announcements and what to do with keyboard events. What I mean by "what to do with keyboard events", this means "switch to-or-from forms mode automatically when the element receives focus".
This means that you need to:
Implement event handlers for keyboard and mouse/touch commands,
Implement the visual styling to convey the state of the component
(e.g. disabled, enabled or selected, not selected etc.), and
Implement the interpretation of the state (so disable the keyboard and
touch/mouse handling when the state is disabled)

Setting an HTML text input box's "default" value. Revert the value when clicking ESC

When a web form is written to the browser, the browsers remembers what the initial values are of a text INPUT box. ie. when it receives HTML like this:
<input type="text" value="something">
The browser remembers "something" as the initial/default value. When the user starts typing over it, then hits ESC, the browser reverts the field to the initial value (or blank if it was initially blank of course).
However, when creating a text input box programatically, hitting ESC always seems to blank the box, even if I create it with a default value like so:
$('<input type="text" value="something">')
The browser doesn't count this as a default value and doesn't revert to it when hitting ESC. So my question is, is there a way to create a text box in code and somehow assign it a default value, so the ESC key works as if the browser received it in the HTML document?
You might looking for the placeholder attribute which will display a grey text in the input field while empty.
From Mozilla Developer Network:
A hint to the user of what can be entered in the control . The
placeholder text must not contain carriage returns or line-feeds. This
attribute applies when the value of the type attribute is text,
search, tel, url or email; otherwise it is ignored.
However as it's a fairly 'new' tag (from the HTML5 specification afaik) you might want to to browser testing to make sure your target audience is fine with this solution.
(If not tell tell them to upgrade browser 'cause this tag works like a charm ;o) )
And finally a mini-fiddle to see it directly in action: http://jsfiddle.net/LnU9t/
Edit: Here is a plain jQuery solution which will also clear the input field if an escape keystroke is detected: http://jsfiddle.net/3GLwE/
This esc behavior is IE only by the way. Instead of using jQuery use good old javascript for creating the element and it works.
var element = document.createElement('input');
element.type = 'text';
element.value = 100;
document.getElementsByTagName('body')[0].appendChild(element);
http://jsfiddle.net/gGrf9/
If you want to extend this functionality to other browsers then I would use jQuery's data object to store the default. Then set it when user presses escape.
//store default value for all elements on page. set new default on blur
$('input').each( function() {
$(this).data('default', $(this).val());
$(this).blur( function() { $(this).data('default', $(this).val()); });
});
$('input').keyup( function(e) {
if (e.keyCode == 27) { $(this).val($(this).data('default')); }
});
If the question is: "Is it possible to add value on ESC" than the answer is yes. You can do something like that. For example with use of jQuery it would look like below.
HTML
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>
<input type="text" value="default!" id="myInput" />
JavaScript
$(document).ready(function (){
$('#myInput').keyup(function(event) {
// 27 is key code of ESC
if (event.keyCode == 27) {
$('#myInput').val('default!');
// Loose focus on input field
$('#myInput').blur();
}
});
});
Working source can be found here: http://jsfiddle.net/S3N5H/1/
Please let me know if you meant something different, I can adjust the code later.
See the defaultValue property of a text input, it's also used when you reset the form by clicking an <input type="reset"/> button (http://www.w3schools.com/jsref/prop_text_defaultvalue.asp )
btw, defaultValue and placeholder text are different concepts, you need to see which one better fits your needs

mootools - using addEvent to element not working properly?

bangin' my head against this and it's starting to hurt.
I'm having trouble with adding an event to an element.
I'm able to add the event, and then call it immediately with element.fireEvent('click'), but once the element is attached to the DOM, it does not react to the click.
example code:
var el = new Element('strong').setStyle('cursor','pointer');
el.addEvent('click',function () { alert('hi!'); });
el.replaces(old_element); // you can assume old_element exists
el.fireEvent('click'); // alert fires
however, once I attach this to the DOM, the element is not reactive to the click. styles stick (cursor is pointer when I mouseover), but no event fires. tried mouseover as well, to no avail.
any clues here? am I missing something basic? I am doing this all over the place, but in this one instance it doesn't work.
EDIT----------------
ok here's some more code. unfortunately I can't expose the real code, as it's for a project that is still under tight wraps.
basically, the nodes all get picked up as "replaceable", then the json found in the rel="" attribute sets the stage for what it should be replaced by. In this particular instance, the replaced element is a user name that should pop up some info when clicked.
again, if I fire the event directly after attaching it, all is good, but the element does not react to the click once it's attached.
HTML-----------
<p>Example: <span class='_mootpl_' rel="{'text':'foo','tag':'strong','event':'click','action':'MyAction','params':{'var1': 'val1','var2': 'val2'}}"></span></p>
JAVASCRIPT-----
assumptions:
1. below two functions are part of a larger class
2. ROOTELEMENT is set at initialize()
3. MyAction is defined before any parsing takes place (and is properly handled on the .fireEvent() test)
parseTemplate: function() {
this.ROOTELEMENT.getElements('span._mootpl_').each(function(el) {
var _c = JSON.decode(el.get('rel'));
var new_el = this.get_replace_element(_c); // sets up the base element
if (_c.hasOwnProperty('event')) {
new_el = this.attach_event(new_el, _c);
}
});
},
attach_event: function(el, _c) {
el.store(_c.event+'-action',_c.action);
el.store('params',_c.params);
el.addEvent(_c.event, function() {
eval(this.retrieve('click-action') + '(this);');
}).setStyle('cursor','pointer');
return el;
},
Works just fine. Test case: http://jsfiddle.net/2GX66/
debugging this is not easy when you lack content / DOM.
first - do you use event delegation or have event handlers on a parent / the parent element that do event.stop()?
if so, replace with event.preventDefault()
second thing to do. do not replace an element but put it somewhere else in the DOM - like document.body's first node and see if it works there.
if it does work elsewhere, see #1
though I realsie you said 'example code', you should write this as:
new Element('strong', {
styles: {
cursor: "pointer"
},
events: {
click: function(event) {
console.log("hi");
}
}
}).replaces(old_element);
no point in doing 3 separate statements and saving a reference if you are not going to reuse it. you really ought to show the ACTUAL code if you need advice, though. in this snippet you don't even set content text so the element won't show if it's inline. could it be a styling issue, what is the display on the element, inline? inline-block?
can you assign it a class that changes it on a :hover pseudo and see it do it? mind you, you say the cursor sticks which means you can mouseover it - hence css works. this also eliminates the possibility of having any element shims above it / transparent els that can prevent the event from bubbling.
finally. assign it an id in the making. assign the event to a parent element via:
parentEl.addEvent("click:relay(strong#idhere)", fn);
and see if it works that way (you need Element.delegate from mootools-more)
good luck, gotta love the weird problems - makes our job worth doing. it wouldn't be the worst thing to post a url or JSFIDDLE too...