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Improving Angular Component’s accessibility

 2 years ago
source link: https://blog.angular.io/improving-angular-components-accessibility-89b8ae904952
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Improving Angular Component’s accessibility

Improving Angular Component’s accessibility

If you’ve looked at the Angular roadmap recently, you’d see that one of the major focuses of the Components team this year is accessibility. The outcome is better, more accessible components.

This work will all come with no change required for application developers, ng update will deliver more accessible Angular Material experiences out of the box.

Along with code changes to the components, we’ve revised and expanded documentation with revised Accessibility sections in each of the material.angular.io component’s overviews and examples. You can view these by selecting any individual component and scrolling to the Accessibility sub-header.

We keep saying the components are more accessible, but how exactly?

My goal in this blog post is to highlight how each component has been improved. If you’re using a standard like WCAG to guide your accessibility practices, this post will outline some of the improvements included just by running ng update.

Improving today’s components and the MDC-Web based components

The migration to integrating MDC Web is currently in progress on the Angular roadmap, and incorporates reusable primitives for building Material Design components to align more closely with the Material Design specification. This upgrade to a newer spec includes a range of built in a11y improvements. Our accessibility review also targeted improving these components as they will be the default moving forward.

You can try out the MDC Web based components in your projects by installing with npm i @angular/material-experimental, then pointing imports of existing components to the experimental updated versions like this:

// Before
import { MatCheckboxModule } from ‘@angular/material/checkbox’;// After
import { MatCheckboxModule } from ‘@angular/material-experimental/mdc-checkbox’;

In an upcoming version, these components will become the default Angular Material components, so all of the following improvements will be built into the mdc-based migration of components. Keep in mind that some of the improvements highlighted below will not land in the default Angular components until this migration is complete.

Component improvements

cdk/a11y

The a11y package provides a number of tools to improve accessibility, like FocusTrap and LiveAnnouncer. These tools are used in multiple components to add accessibility functionality.

FocusMonitor now correctly detects fake mousedown events from screen readers.

This helps ensure that when focus and click events happen on the screen, they are correctly interpreted by your applications.

Video shows navigation between two focused Button elements recognizing both click and keyboard events.
Video shows navigation between two focused Button elements recognizing both click and keyboard events.
Video shows navigation between two focused Button elements recognizing both click and keyboard events.

This also includes more granular detection of input modality such as keyboard, mouse and touch events.

Badge

Better ARIA descriptions

The badge’s description is now applied to the badge’s host element via aria-describedby. The component previously applied an aria-label, which was not the best way to communicate the augmentative nature of the badge.

<button mat-stroked-button matBadge="7" matBadgeDescription="7 unread messages">
Inbox
</button>

Bottom Sheet

Add autoFocus options for initial focus when a bottom sheet is opened

When opened, MatBottomSheet traps browser focus. By default, the first tabbable element in the bottom sheet receives focus. You can now customize which element receives focus with the autoFocus property of MatBottomSheetConfig.

openBottomSheet() {
const bottomSheetConfig = new MatBottomSheetConfig();
bottomSheetConfig.autoFocus = '.custom-tab-header' return this.bottomSheet.open(this.template, config);
}

Button

Buttons in High Contrast Mode with correct styling.
Buttons in High Contrast Mode with correct styling.
Buttons in High Contrast Mode with correct styling.

High contrast outline for solitary icon-buttons

Icon buttons now have correct styling in high contrast mode when on pages that contain no other buttons.

Buttons with the inspect element panel showing an increased touch target size of 56 x 56.
Buttons with the inspect element panel showing an increased touch target size of 56 x 56.
Buttons with the inspect element panel showing an increased touch target size of 56 x 56.

Touch target sizes

The buttons, and several other components, now utilize MDC-Web’s specs for larger touch target sizes. This means there is more area in a button to successfully navigate and click.

Checkbox

Screen readers no longer read svg images within the checkbox during selection.

Expands the touch target size for checkbox selection. (MDC only)

MDC-Checkboxes with the inspect element panel showing expanded touch target of 40 x 40 on the focusable region of the checkbox.
MDC-Checkboxes with the inspect element panel showing expanded touch target of 40 x 40 on the focusable region of the checkbox.
MDC-Checkboxes with the inspect element panel showing expanded touch target of 40 x 40 on the focusable region of the checkbox.

Chips

Guidance on matChipRemove

matChipRemove is a directive which provides styling and behavior for removing chips from a list.

In the past, this directive appeared in documentation applied to <mat-icon>, which provides limited accessibility when clicked. New documentation and styling defines the best practice to apply matChipRemove to a <button> with a nested <mat-icon>, so that the button click is more accessible for users, with the same visual appearance.

<button matChipRemove *ngIf="removable">
<mat-icon>cancel</mat-icon>
</button>

Datepicker

There’s a bunch here because accessible date-pickers are, well, picky.

Changes include:

The team is continuing to invest in additional Datepicker improvements in Q4 that will land in future versions of Angular.

Angular Datepicker in High Contrast mode.
Angular Datepicker in High Contrast mode.
Angular Datepicker in High Contrast mode.

Dialog

Add autoFocus options for initial focus when a dialog is opened

Previously, autoFocus was a boolean that allowed users to specify whether the container element or the first tabbable element is focused on dialog open. Now you can also specify focusing the first header element or use a CSS selector and focus the first element that matches that. If these elements can’t be focused, then the container element is focused by default.

openDialog() {
const dialogConfig = new MatDialogConfig();
dialogConfig.autoFocus = '.custom-dialog-tab' this.matDialog.open(DialogBodyComponent, dialogConfig);
}

Better screen reader experience when opening a dialog

Screen readers now read the dialog title, role, content, and then inform the user about the focused element after being opened, following W3 best practices.

The dialog also avoids opening multiple of the same dialog before animations complete. In previous versions we moved the focus twice on dialog launch, sometimes confusing screen readers and missing the announcement that a dialog was opened. We now only move focus once, and block the user from opening repeats of the same dialog while one is animating open.

Expansion Panel

Add a bottom border to headers in high-contrast code.

Before: Expansion Panel in High Contrast mode is missing a border.
Before: Expansion Panel in High Contrast mode is missing a border.
Before: Expansion Panel in High Contrast mode is missing a border.
After: Improved Expansion Panel in High Contrast mode.
After: Improved Expansion Panel in High Contrast mode.
After: Improved Expansion Panel in High Contrast mode.

Form field

Adds missing focus indicator for outline appearance in high-contrast mode.

Before: Form field is missing focus indicator.
Before: Form field is missing focus indicator.
Before: Form field is missing focus indicator.
After: Form field focus indicator improves High Contrast mode.
After: Form field focus indicator improves High Contrast mode.
After: Form field focus indicator improves High Contrast mode.

Input

Show focus indication for readonly inputs

A long time ago we disabled focus indication on readonly inputs in order to mimic the native browser behavior, this reverses these changes to match best practices.

Updates how screen readers announce inputs in invalid states

Allows aria-invalid on matInput if the input is required and has no value so that screen readers can inform users of the input’s invalid state.

action-list focus state for high contrast mode in Firefox

Action list focus state shows “Inbox” list-item is focused.
Action list focus state shows “Inbox” list-item is focused.
Action list focus state shows “Inbox” list-item is focused.

Set initial focus on first selected option in selection list

Initial focus is set on the first selected option and falls back to the first option, so a user experiencing a selection for the first time is more informed of their options.

List shows focus indicator on the first list-item of “Boots” in list of five shoe type options.
List shows focus indicator on the first list-item of “Boots” in list of five shoe type options.
List shows focus indicator on the first list-item of “Boots” in list of five shoe type options.

Adds submenu icon support in high contrast mode

We originally rendered this little triangle with a clever CSS trick. It turned out this was too clever and didn’t render correctly in high contrast mode. It’s just an SVG now.

Submenu has right black triangle option in High Contrast mode of menu with nested selection of types of Vertebrates.
Submenu has right black triangle option in High Contrast mode of menu with nested selection of types of Vertebrates.
Submenu has right black triangle option in High Contrast mode of menu with nested selection of types of Vertebrates.

Paginator

Add screen reader announcement for current range when navigating between pages

The paginator will now read and announce navigation and page ranges.

Adds aria-labelledby support

Also adds role=”group” to the Paginator element

Paginator example with increased ARIA support.
Paginator example with increased ARIA support.
Paginator example with increased ARIA support.

Progress bar and Progress spinner

Make progress indicators reachable by screen readers

This sets the tab index to -1 so screen readers will read the aria-label.

Radio button

Adds accessible touch targets on the radio button.

Radio button with the inspect element panel showing expanded touch target of 40 x 40.
Radio button with the inspect element panel showing expanded touch target of 40 x 40.
Radio button with the inspect element panel showing expanded touch target of 40 x 40.

Select

Better visuals in high contrast mode

This removes the small rectangle rendered over the select placeholder text and makes the dropdown arrow visible.

Before: Select is missing a visible dropdown arrow and text is partially obstructed.
Before: Select is missing a visible dropdown arrow and text is partially obstructed.
Before: Select is missing a visible dropdown arrow and text is partially obstructed.
After: Select has clear text and dropdown in High Contrast mode.
After: Select has clear text and dropdown in High Contrast mode.
After: Select has clear text and dropdown in High Contrast mode.

Sidenav

Similar to Dialog, autoFocus now has expanded options for initial focus.

When opened, Sidenav can trap browser focus. By default, the first tabbable element in the bottom sheet receives focus. You can customize which element receives focus with the autoFocus property to ’dialog’ | ‘first-tabbable’ | ‘first-heading’ or a CSS custom selector.

Slide toggle

Increase the contrast of disabled slide toggles in high contrast mode.

Slide Toggle label text has contrast of 15.54 when the toggle is disabled.
Slide Toggle label text has contrast of 15.54 when the toggle is disabled.
Slide Toggle label text has contrast of 15.54 when the toggle is disabled.

Slider

Adds a strong focus indicator

Slider is slid to 54 out of 100 with label and has strong focus option.
Slider is slid to 54 out of 100 with label and has strong focus option.
Slider is slid to 54 out of 100 with label and has strong focus option.

Sort header

Add description input for sort-header

Adds a description input for mat-sort-header so that developers can provide an accessible description (using AriaDescirber under the hood). Additionally update the accessibility section for the sort header’s documentation with guidance on providing an accessible experience.

<table mat-table [dataSource]="dataSource" matSort (matSortChange)="announceSortChange($event)"
class="mat-elevation-z8">

<! - Position Column →
<ng-container matColumnDef="position">
<th mat-header-cell *matHeaderCellDef mat-sort-header sortActionDescription="Sort by number">
No.
</th>
<td mat-cell *matCellDef="let element"> {{element.position}} </td>
</ng-container>

<! - Name Column →
<ng-container matColumnDef="name">
<th mat-header-cell *matHeaderCellDef mat-sort-header sortActionDescription="Sort by name">
Name
</th>
<td mat-cell *matCellDef="let element"> {{element.name}} </td>
</ng-container> <! - Weight Column →
<ng-container matColumnDef="weight">
<th mat-header-cell *matHeaderCellDef mat-sort-header sortActionDescription="Sort by weight">
Weight
</th>
<td mat-cell *matCellDef="let element"> {{element.weight}} </td>
</ng-container> <! - Symbol Column →
<ng-container matColumnDef="symbol">
<th mat-header-cell *matHeaderCellDef mat-sort-header sortActionDescription="Sort by symbol">
Symbol
</th>
<td mat-cell *matCellDef="let element"> {{element.symbol}} </td>
</ng-container>
</table>

Stepper

The stepper received a number of updates including:

Stepper in High Contrast mode.
Stepper in High Contrast mode.
Stepper in High Contrast mode.

Table

Adds default role to ‘table’

Adds role=”table” to the html element. When we originally built the table, we assumed that most MatTable instances would be rich, interactive tables, so we applied role=”grid”. But after seeing how developers use MatTable, we determined that role=”table” is actually more appropriate for the most common cases.

You can still set role=”grid” on the <table> element and all of the appropriate descendent roles will apply (e.g. gridcell), but MatTable doesn’t currently provide any of the expected keyboard interaction for role=”grid”.

Increase functionality when using both tabbing and keyboard events

We now keep the ListKeyManager state up-to-date on tab navigation so that tabs can be fully interact-able with both Tab and keyboard events.

Tabs shows focus on the Second tab header with navigation by tabbing and keyboard.
Tabs shows focus on the Second tab header with navigation by tabbing and keyboard.
Tabs shows focus on the Second tab header with navigation by tabbing and keyboard.

Tooltip

Increase color contrast on the tooltip

This makes the background color opaque to increase the contrast and make the tooltip more readable.

Before: Tooltip contrast depends on text underneath.
Before: Tooltip contrast depends on text underneath.
Before: Tooltip contrast depends on text underneath.
After: Tooltip contrast is more consistent.
After: Tooltip contrast is more consistent.
After: Tooltip contrast is more consistent.

Thank you for continuing to develop with accessibility in mind!

If you notice an additional a11y improvement we can make to components, please open an issue on the angular/components GitHub.


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