We have a template-based form that uses the various Angular Material controls (matInput, mat-select, etc). We want to create a 'read-only' type view for some users. My immediate thought was to simply check a user's privileges and then loop through all form controls and set them to disable if need be.
This appears to work for text input type controls but is not working for selects and checkboxes. Plus this grays-out the controls which isn't necessarily what we want.
Any ideas on how to best accomplish this? Perhaps somehow disable keyboard and mouse input within the form might be what we want but I have no idea how to go about this.
I think it is possible, but you will have to check all control types, for example MatInput exposes readonly property, it allows us to create simple directive which will switch readonly state for entire form:
import {Directive, ContentChildren, QueryList, AfterContentInit, Input} from '#angular/core';
import {NgModel} from '#angular/forms';
#Directive({
selector: 'form[readonly]'
})
export class FormReadonlyDirective implements AfterContentInit
{
#ContentChildren(NgModel)
public inputs:QueryList<NgModel>;
private controls:any[];
private _readonly:boolean = false;
public ngAfterContentInit():void
{
this.controls = this.getControls();
this.inputs.changes.subscribe(() =>
{
this.setReadonly(this.readonly);
});
this.setReadonly(this.readonly);
}
#Input()
public get readonly():boolean
{
return this._readonly;
}
public set readonly(value:boolean)
{
this._readonly = value != null && value !== false && `${value}` !== 'false';
this.setReadonly(value);
}
private setReadonly(value:boolean):void
{
if(this.controls != null)
{
this.controls.forEach(control =>
{
//todo: check
control.readonly = value;
});
}
}
private getControls():any[]
{
return this.inputs.map(control => control.valueAccessor);
}
}
Not tested, but you get the idea.
I'm developing an app with Angular and Semantic-UI. The app should be accessible, this means it should be compliant with WCAG 2.0.
To reach this purpose the modals should keep focus within the dialog and prevents users from going outside or move with "tabs" between elements of the page that lays under the modal.
I have found some working examples, like the following:
JQuery dialog: https://jqueryui.com/dialog/#modal-confirmation
dialog HTML 5.1 element: https://demo.agektmr.com/dialog
ARIA modal dialog example:
http://w3c.github.io/aria-practices/examples/dialog-modal/dialog.html
(that I have reproduced on Plunker)
Here is my try to create an accessible modal with Semantic-UI: https://plnkr.co/edit/HjhkZg
As you can see I used the following attributes:
role="dialog"
aria-labelledby="modal-title"
aria-modal="true"
But they don't solve my issue. Do you know any way to make my modal keeping focus and lose it only when user click on cancel/confirm buttons?
There is currently no easy way to achieve this. The inert attribute was proposed to try to solve this problem by making any element with the attribute and all of it's children inaccessible. However, adoption has been slow and only recently did it land in Chrome Canary behind a flag.
Another proposed solution is making a native API that would keep track of the modal stack, essentially making everything not currently the top of the stack inert. I'm not sure the status of the proposal, but it doesn't look like it will be implemented any time soon.
So where does that leave us?
Unfortunately without a good solution. One solution that is popular is to create a query selector of all known focusable elements and then trap focus to the modal by adding a keydown event to the last and first elements in the modal. However, with the rise of web components and shadow DOM, this solution can no longer find all focusable elements.
If you always control all the elements within the dialog (and you're not creating a generic dialog library), then probably the easiest way to go is to add an event listener for keydown on the first and last focusable elements, check if tab or shift tab was used, and then focus the first or last element to trap focus.
If you're creating a generic dialog library, the only thing I have found that works reasonably well is to either use the inert polyfill or make everything outside of the modal have a tabindex=-1.
var nonModalNodes;
function openDialog() {
var modalNodes = Array.from( document.querySelectorAll('dialog *') );
// by only finding elements that do not have tabindex="-1" we ensure we don't
// corrupt the previous state of the element if a modal was already open
nonModalNodes = document.querySelectorAll('body *:not(dialog):not([tabindex="-1"])');
for (var i = 0; i < nonModalNodes.length; i++) {
var node = nonModalNodes[i];
if (!modalNodes.includes(node)) {
// save the previous tabindex state so we can restore it on close
node._prevTabindex = node.getAttribute('tabindex');
node.setAttribute('tabindex', -1);
// tabindex=-1 does not prevent the mouse from focusing the node (which
// would show a focus outline around the element). prevent this by disabling
// outline styles while the modal is open
// #see https://www.sitepoint.com/when-do-elements-take-the-focus/
node.style.outline = 'none';
}
}
}
function closeDialog() {
// close the modal and restore tabindex
if (this.type === 'modal') {
document.body.style.overflow = null;
// restore or remove tabindex from nodes
for (var i = 0; i < nonModalNodes.length; i++) {
var node = nonModalNodes[i];
if (node._prevTabindex) {
node.setAttribute('tabindex', node._prevTabindex);
node._prevTabindex = null;
}
else {
node.removeAttribute('tabindex');
}
node.style.outline = null;
}
}
}
The different "working examples" do not work as expected with a screenreader.
They do not trap the screenreader visual focus inside the modal.
For this to work, you have to :
Set the aria-hidden attribute on any other nodes
disable keyboard focusable elements inside those trees (links using tabindex=-1, controls using disabled, ...)
The jQuery :focusable pseudo selector can be useful to find focusable elements.
add a transparent layer over the page to disable mouse selection.
or you can use the css pointer-events: none property when the browser handles it with non SVG elements, not in IE
This focus-trap plugin is excellent at making sure that focus stays trapped inside of dialogue elements.
It sounds like your problem can be broken down into 2 categories:
focus on dialog box
Add a tabindex of -1 to the main container which is the DOM element that has role="dialog". Set the focus to the container.
wrapping the tab key
I found no other way of doing this except by getting the tabbable elements within the dialog box and listening it on keydown. When I know the element in focus (document.activeElement) is the last one on the list, I make it wrap
"focus" events can be intercepted in the capture phase, so you can listen for them at the document.body level, squelch them before they reach the target element, and redirect focus back to a control in your modal dialog. This example assumes a modal dialog with an input element gets displayed and assigned to the variable currDialog:
document.body.addEventListener("focus", (event) => {
if (currDialog && !currDialog.contains(event.target)) {
event.preventDefault();
event.stopPropagation();
currDialog.querySelector("input").focus();
}
}, {capture: true});
You may also want to contain such a dialog in a fixed-position, clear (or low-opacity) backdrop element that takes up the full screen in order to capture and suppress mouse/pointer events, so that no browser feedback (hover, etc.) occurs that could give the user the impression that the background is active.
Don't use any solution requiring you to look up "tabbable" elements. Instead, use keydown and either click events or a backdrop in an effective manor.
(Angular1)
See Asheesh Kumar's answer at https://stackoverflow.com/a/31292097/1754995 for something similar to what I am going for below.
(Angular2-x, I haven't done Angular1 in a while)
Say you have 3 components: BackdropComponent, ModalComponent (has an input), and AppComponent (has an input, the BackdropComponent, and the ModalComponent). You display BackdropComponent and ModalComponent with the correct z-index, both are currently displayed/visible.
What you need to do is have a general window.keydown event with preventDefault() to stop all tabbing when the backdrop/modal component is displayed. I recommend you put that on a BackdropComponent. Then you need a keydown.tab event with stopPropagation() to handle tabbing for the ModalComponent. Both the window.keydown and keydown.tab could probably be in the ModalComponent but there is purpose in a BackdropComponent further than just modals.
This should prevent clicking and tabbing to the AppComponent input and only click or tab to the ModalComponent input [and browser stuffs] when the modal is shown.
If you don't want to use a backdrop to prevent clicking, you can use use click events similarly to the keydown events described above.
Backdrop Component:
#Component({
selector: 'my-backdrop',
host: {
'tabindex': '-1',
'(window:keydown)': 'preventTabbing($event)'
},
...
})
export class BackdropComponent {
...
private preventTabbing(event: KeyboardEvent) {
if (event.keyCode === 9) { // && backdrop shown?
event.preventDefault();
}
}
...
}
Modal Component:
#Component({
selector: 'my-modal',
host: {
'tabindex': '-1',
'(keydown.tab)': 'onTab($event)'
},
...
})
export class ModalComponent {
...
private onTab(event: KeyboardEvent) {
event.stopPropagation();
}
...
}
Here's my solution. It traps Tab or Shift+Tab as necessary on first/last element of modal dialog (in my case found with role="dialog"). Eligible elements being checked are all visible input controls whose HTML may be input,select,textarea,button.
$(document).on('keydown', function(e) {
var target = e.target;
var shiftPressed = e.shiftKey;
// If TAB key pressed
if (e.keyCode == 9) {
// If inside a Modal dialog (determined by attribute role="dialog")
if ($(target).parents('[role=dialog]').length) {
// Find first or last input element in the dialog parent (depending on whether Shift was pressed).
// Input elements must be visible, and can be Input/Select/Button/Textarea.
var borderElem = shiftPressed ?
$(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').first()
:
$(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').last();
if ($(borderElem).length) {
if ($(target).is($(borderElem))) {
return false;
} else {
return true;
}
}
}
}
return true;
});
we can use the focus trap npm package.
npm i focus-trap
This might help someone who is looking for solution in Angular.
Step 1: Add keydown event on dialog component
#HostListener('document:keydown', ['$event'])
handleTabKeyWInModel(event: any) {
this.sharedService.handleTabKeyWInModel(event, '#modal_id', this.elementRef.nativeElement, 'input,button,select,textarea,a,[tabindex]:not([tabindex="-1"])');
}
This will filters the elements which are preseneted in the Modal dialog.
Step 2: Add common method to handle focus in shared service (or you can add it in your component as well)
handleTabKeyWInModel(e, modelId: string, nativeElement, tagsList: string) {
if (e.keyCode === 9) {
const focusable = nativeElement.querySelector(modelId).querySelectorAll(tagsList);
if (focusable.length) {
const first = focusable[0];
const last = focusable[focusable.length - 1];
const shift = e.shiftKey;
if (shift) {
if (e.target === first) { // shift-tab pressed on first input in dialog
last.focus();
e.preventDefault();
}
} else {
if (e.target === last) { // tab pressed on last input in dialog
first.focus();
e.preventDefault();
}
}
}
}
}
Now this method will take the modal dialog native element and start evaluate on every tab key. Finally we will filter the event on first and last so that we can focus on appropriate elements (on first after last element tab click and on last shift+tab event on first element).
Happy Coding.. :)
I used one of the methods suggested by Steven Lambert, namely, listening to keydown events and intercepting "tab" and "shift+tab" keys. Here's my sample code (Angular 5):
import { Directive, ElementRef, Attribute, HostListener, OnInit } from '#angular/core';
/**
* This directive allows to override default tab order for page controls.
* Particularly useful for working around the modal dialog TAB issue
* (when tab key allows to move focus outside of dialog).
*
* Usage: add "custom-taborder" and "tab-next='next_control'"/"tab-prev='prev_control'" attributes
* to the first and last controls of the dialog.
*
* For example, the first control is <input type="text" name="ctlName">
* and the last one is <button type="submit" name="btnOk">
*
* You should modify the above declarations as follows:
* <input type="text" name="ctlName" custom-taborder tab-prev="btnOk">
* <button type="submit" name="btnOk" custom-taborder tab-next="ctlName">
*/
#Directive({
selector: '[custom-taborder]'
})
export class CustomTabOrderDirective {
private elem: HTMLInputElement;
private nextElemName: string;
private prevElemName: string;
private nextElem: HTMLElement;
private prevElem: HTMLElement;
constructor(
private elemRef: ElementRef
, #Attribute('tab-next') public tabNext: string
, #Attribute('tab-prev') public tabPrev: string
) {
this.elem = this.elemRef.nativeElement;
this.nextElemName = tabNext;
this.prevElemName = tabPrev;
}
ngOnInit() {
if (this.nextElemName) {
var elems = document.getElementsByName(this.nextElemName);
if (elems && elems.length && elems.length > 0)
this.nextElem = elems[0];
}
if (this.prevElemName) {
var elems = document.getElementsByName(this.prevElemName);
if (elems && elems.length && elems.length > 0)
this.prevElem = elems[0];
}
}
#HostListener('keydown', ['$event'])
onKeyDown(event: KeyboardEvent) {
if (event.key !== "Tab")
return;
if (!event.shiftKey && this.nextElem) {
this.nextElem.focus();
event.preventDefault();
}
if (event.shiftKey && this.prevElem) {
this.prevElem.focus();
event.preventDefault();
}
}
}
To use this directive, just import it to your module and add to Declarations section.
I've been successful using Angular Material's A11yModule.
Using your favorite package manager install these to packages into your Angular app.
**"#angular/material": "^10.1.2"**
**"#angular/cdk": "^10.1.2"**
In your Angular module where you import the Angular Material modules add this:
**import {A11yModule} from '#angular/cdk/a11y';**
In your component HTML apply the cdkTrapFocus directive to any parent element, example: div, form, etc.
Run the app, tabbing will now be contained within the decorated parent element.
For jquery users:
Assign role="dialog" to your modal
Find first and last interactive element inside the dialog modal.
Check if current target is one of them(depending on shift key is
pressed or not).
If target element is one of first or last interactive element of the
dialog, return false
Working code sample:
//on keydown inside dialog
$('.modal[role=dialog]').on('keydown', e => {
let target = e.target;
let shiftPressed = e.shiftKey;
// If TAB is pressed
if (e.keyCode === 9) {
// Find first and last element in the ,modal-dialog parent.
// Elements must be interactive i.e. visible, and can be Input/Select/Button/Textarea.
let first = $(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').first();
let last = $(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').last();
let borderElem = shiftPressed ? first : last //border element on the basis of shift key pressed
if ($(borderElem).length) {
return !$(target).is($(borderElem)); //if target is border element , return false
}
}
return true;
});
I read through most of the answers, while the package focus-trap seems like a good option. #BenVida shared a very simple VanillaJS solution here in another Stack Overflow post.
Here is the code:
const container=document.querySelector("_selector_for_the_container_")
//optional: needed only if the container element is not focusable already
container.setAttribute("tabindex","0")
container.addEventListener("focusout", (ev)=>{
if (!container.contains(ev.relatedTarget)) container.focus()
})
I created a new tool in ContentTools that adds a static table (I don't want you to edit).
But being a static element doesn't maintain focus and I can not remove it when I click remove button.
I can do so that the table is not editable but can be removed if you click on it?
That's how I created the element:
new ContentEdit.Static('div', {'data-ce-moveable': true}, '<table><thead><tr><th>Foo head</th></tr></thead><tbody><tr><td>Foo body</td></tr></tbody></table>')
Thank you!
Static elements can't be interacted with for the most part (other elements can be dragged around them but that's about it). ContentEdit/Tools does allow you to restrict the some behaviour for elements but not being able to modify the content of a text element isn't one right now (though I think this might be a worthy addition).
However whilst there's no set way to do this at the moment here's an approach you can use that should provide the behaviour you describe (do let me know how you get on):
ContentEdit.Root.get().bind('mount', function(element) {
// We only care about `TableCell` elements
if (element.type() != 'TableCell') {
return;
}
// We only want to make the element read-only if the parent table has
// the `data-read-only` attribute.
var table = element.closest(function(node) {
return node.type() == 'Table';
});
if (table.attr('data-read-only') !== undefined) {
// Disable text editing for the table cell
element.tableCellText()._onKeyDown = function(ev) {
ev.preventDefault();
}
}
// Disable dragging of the table rows
var tableRow = element.closest(function(node) {
return node.type() == 'TableRow';
});
tableRow.can('drag', false);
tableRow.can('drop', false);
});
I am working in extjs4. I am having form with multiple textboxes,radio buttons and some more elements.Suppose i clicked on modify form. If user made some editing in form,then i want to display message box window in order to ask confirmation of saving of changes that user has made.If user closes form without any modifications,then that messagebox should not be appear.I was trying to use dirtychange event of form as-
me.getForm().on('dirtychange', function(form, isDirty) {
console.log(form.events);
if( isDirty ) {
isChanged=true;
}
else {
isChanged=false;
}
});
But its setting isChanged variable to always true though form is not modified.
So how to identify whether form is modified or not so that i can display confirmation message box.
You can use Ext.data.Model-property-dirty to determine if a record has been modified.
form.getRecord().dirty
If your record is dirty without you making any modifications, you can try this to find which field is dirty.
if (form.isDirty()) {
var fields = form.getForm().getFields().items;
for (var i=0; i<fields.length; i++) {
if (fields[i].isDirty()) {
if (Ext.isDefined(fields[i].name)) {
alert(fields[i].name);
}
}
}
}
I have a CheckBox with a handler attached to the select event. In this function is the code to dynamically populate/ display few fields. If I come on the screen and the data brings in a value which makes the checkbox selected already, then those fields are not displayed (because they become visible only when I select the checkbox).
I want to ensure that if the CheckBox is auto selected, still I should be able to process the logic in the function, which has oEvent as an input parameter. But the issue is that if I call this function from another method, that function does not work as it has many statements like oEvent().getSource() which I do not pass.
Controller.js
onCheckBoxSelect: function(oEvent) {
var cells = sap.ui.getCore().byId("cell");
controlCell.destroyContent();
vc.abc();
var material= sap.ui.getCore().byId("abc");
var isSelected = oEvent.getParameters("selected").selected;
if (isSelected) {
// ...
}
},
someFunction : function(){
if(true){
// want to call onCheckBoxSelect here
}
// ...
},
If you assign an ID to your checkbox, you can get the checkbox in any function you want as long as it is known in the view. By doing that you won't need the oEvent which is only available when an event on the checkbox is executed.
Example:
var cb = this.byId('checkboxId');
if(cb.getProperty('selected')) {
// execute code
} else {
// do something else
}
Decouple the handler body into a separate function so that other functions can call the decoupled function with the right arguments. For example:
Controller
onCheckBoxSelect: function(oEvent) {
const bSelected = oEvent.getParameter("selected");
this.doIt(bSelected); // Instead of "doing it" all here
},
someFunction: function(){
if (/*Something truthy*/) {
const checkBox = this.byId("myCheckBox");
const bSelected = checkBox.getSelected();
doIt(bSelected); // passing the same argument as in onCheckBoxSelect
}
// ...
},
doIt: function(bSelected) { // decoupled from onCheckBoxSelect
// ...
if (bSelected) {
// ...
}
},
View
<CheckBox id="myCheckBox"
select=".onCheckBoxSelect"
/>
Or since 1.56:
<CheckBox id="myCheckBox"
select=".doIt(${$parameters>/selected})"
/>
Docu: Handling Events in XML Views
By that, you can have a pure, decoupled function that can be called from anywhere.
I would suggest a different approach. Use the same property that you have used in your checkbox binding, to determine the visibility of the other fields, i.e. bind the visible property of each relevant field to that property in your model.
If there is additional post-processing required in populating the fields, you can either use expression binding or custom formatter for field-specific processing, or model binding events if you need to do a bit more "staging" work (in which case you would probably store the resultant data in a client model and bind to that for populating your fields).