Merge pull request #653 from greatislander/tab-keyboard-accessibility

feature: keyboard accessibility for tabbed UIs (fixes #526)
This commit is contained in:
Mouse Reeve 2021-02-28 11:11:54 -08:00 committed by GitHub
commit 310d4a1f59
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5 changed files with 336 additions and 94 deletions

View file

@ -12,9 +12,9 @@ window.onload = function() {
Array.from(document.getElementsByClassName('select-all'))
.forEach(t => t.onclick = selectAll);
// toggle between tabs
Array.from(document.getElementsByClassName('tab-change'))
.forEach(t => t.onclick = tabChange);
// tab groups
Array.from(document.getElementsByClassName('tab-group'))
.forEach(t => new TabGroup(t));
// handle aria settings on menus
Array.from(document.getElementsByClassName('pulldown-menu'))
@ -141,23 +141,6 @@ function selectAll(e) {
.forEach(t => t.checked=true);
}
function tabChange(e) {
var el = e.currentTarget;
var parentElement = el.closest('[role="tablist"]');
parentElement.querySelectorAll('[aria-selected="true"]')
.forEach(t => t.setAttribute("aria-selected", false));
el.setAttribute("aria-selected", true);
parentElement.querySelectorAll('li')
.forEach(t => removeClass(t, 'is-active'));
addClass(el, 'is-active');
var tabId = el.getAttribute('data-tab');
Array.from(document.getElementsByClassName(el.getAttribute('data-category')))
.forEach(t => addRemoveClass(t, 'hidden', t.id != tabId));
}
function toggleMenu(e) {
var el = e.currentTarget;
var expanded = el.getAttribute('aria-expanded') == 'false';
@ -203,3 +186,258 @@ function removeClass(el, className) {
}
el.className = classes.join(' ');
}
/*
* The content below is licensed according to the W3C Software License at
* https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
* Heavily modified to web component by Zach Leatherman
* Modified back to vanilla JavaScript with support for Bulma markup and nested tabs by Ned Zimmerman
*/
class TabGroup {
constructor(container) {
this.container = container;
this.tablist = this.container.querySelector('[role="tablist"]');
this.buttons = this.tablist.querySelectorAll('[role="tab"]');
this.panels = this.container.querySelectorAll(':scope > [role="tabpanel"]');
this.delay = this.determineDelay();
if(!this.tablist || !this.buttons.length || !this.panels.length) {
return;
}
this.keys = this.keys();
this.direction = this.direction();
this.initButtons();
this.initPanels();
}
keys() {
return {
end: 35,
home: 36,
left: 37,
up: 38,
right: 39,
down: 40
};
}
// Add or substract depending on key pressed
direction() {
return {
37: -1,
38: -1,
39: 1,
40: 1
};
}
initButtons() {
let count = 0;
for(let button of this.buttons) {
let isSelected = button.getAttribute("aria-selected") === "true";
button.setAttribute("tabindex", isSelected ? "0" : "-1");
button.addEventListener('click', this.clickEventListener.bind(this));
button.addEventListener('keydown', this.keydownEventListener.bind(this));
button.addEventListener('keyup', this.keyupEventListener.bind(this));
button.index = count++;
}
}
initPanels() {
let selectedPanelId = this.tablist.querySelector('[role="tab"][aria-selected="true"]').getAttribute("aria-controls");
for(let panel of this.panels) {
if(panel.getAttribute("id") !== selectedPanelId) {
panel.setAttribute("hidden", "");
}
panel.setAttribute("tabindex", "0");
}
}
clickEventListener(event) {
let button = event.target.closest('a');
event.preventDefault();
this.activateTab(button, false);
}
// Handle keydown on tabs
keydownEventListener(event) {
var key = event.keyCode;
switch (key) {
case this.keys.end:
event.preventDefault();
// Activate last tab
this.activateTab(this.buttons[this.buttons.length - 1]);
break;
case this.keys.home:
event.preventDefault();
// Activate first tab
this.activateTab(this.buttons[0]);
break;
// Up and down are in keydown
// because we need to prevent page scroll >:)
case this.keys.up:
case this.keys.down:
this.determineOrientation(event);
break;
};
}
// Handle keyup on tabs
keyupEventListener(event) {
var key = event.keyCode;
switch (key) {
case this.keys.left:
case this.keys.right:
this.determineOrientation(event);
break;
};
}
// When a tablists aria-orientation is set to vertical,
// only up and down arrow should function.
// In all other cases only left and right arrow function.
determineOrientation(event) {
var key = event.keyCode;
var vertical = this.tablist.getAttribute('aria-orientation') == 'vertical';
var proceed = false;
if (vertical) {
if (key === this.keys.up || key === this.keys.down) {
event.preventDefault();
proceed = true;
};
}
else {
if (key === this.keys.left || key === this.keys.right) {
proceed = true;
};
};
if (proceed) {
this.switchTabOnArrowPress(event);
};
}
// Either focus the next, previous, first, or last tab
// depending on key pressed
switchTabOnArrowPress(event) {
var pressed = event.keyCode;
for (let button of this.buttons) {
button.addEventListener('focus', this.focusEventHandler.bind(this));
};
if (this.direction[pressed]) {
var target = event.target;
if (target.index !== undefined) {
if (this.buttons[target.index + this.direction[pressed]]) {
this.buttons[target.index + this.direction[pressed]].focus();
}
else if (pressed === this.keys.left || pressed === this.keys.up) {
this.focusLastTab();
}
else if (pressed === this.keys.right || pressed == this.keys.down) {
this.focusFirstTab();
}
}
}
}
// Activates any given tab panel
activateTab (tab, setFocus) {
if(tab.getAttribute("role") !== "tab") {
tab = tab.closest('[role="tab"]');
}
setFocus = setFocus || true;
// Deactivate all other tabs
this.deactivateTabs();
// Remove tabindex attribute
tab.removeAttribute('tabindex');
// Set the tab as selected
tab.setAttribute('aria-selected', 'true');
// Give the tab parent an is-active class
tab.parentNode.classList.add('is-active');
// Get the value of aria-controls (which is an ID)
var controls = tab.getAttribute('aria-controls');
// Remove hidden attribute from tab panel to make it visible
document.getElementById(controls).removeAttribute('hidden');
// Set focus when required
if (setFocus) {
tab.focus();
}
}
// Deactivate all tabs and tab panels
deactivateTabs() {
for (let button of this.buttons) {
button.parentNode.classList.remove('is-active');
button.setAttribute('tabindex', '-1');
button.setAttribute('aria-selected', 'false');
button.removeEventListener('focus', this.focusEventHandler.bind(this));
}
for (let panel of this.panels) {
panel.setAttribute('hidden', 'hidden');
}
}
focusFirstTab() {
this.buttons[0].focus();
}
focusLastTab() {
this.buttons[this.buttons.length - 1].focus();
}
// Determine whether there should be a delay
// when user navigates with the arrow keys
determineDelay() {
var hasDelay = this.tablist.hasAttribute('data-delay');
var delay = 0;
if (hasDelay) {
var delayValue = this.tablist.getAttribute('data-delay');
if (delayValue) {
delay = delayValue;
}
else {
// If no value is specified, default to 300ms
delay = 300;
};
};
return delay;
}
focusEventHandler(event) {
var target = event.target;
setTimeout(this.checkTabFocus.bind(this), this.delay, target);
};
// Only activate tab on focus if it still has focus after the delay
checkTabFocus(target) {
let focused = document.activeElement;
if (target === focused) {
this.activateTab(target, false);
}
}
}

View file

@ -10,56 +10,58 @@
{% if not suggested_books %}
<p>{% trans "There are no books here right now! Try searching for a book to get started" %}</p>
{% else %}
<div class="tabs is-small">
<ul role="tablist">
{% for shelf in suggested_books %}
{% if shelf.books %}
{% with shelf_counter=forloop.counter %}
<li>
<p>
{{ shelf.name }}
</p>
<div class="tabs is-small is-toggle">
<ul>
{% for book in shelf.books %}
<li class="tab-change{% if shelf_counter == 1 and forloop.first %} is-active{% endif %}" data-tab="book-{{ book.id }}" data-tab="book-{{ book.id }}" role="tab" tabindex="0" aria-selected="{% if shelf_counter == 1 and forloop.first %}true{% else %}false{% endif %}" aria-controls="book-{{ book.id }}" data-category="suggested-tabs">
<a>
{% include 'snippets/book_cover.html' with book=book size="medium" %}
</a>
</li>
{% endfor %}
</ul>
</div>
</li>
{% endwith %}
{% endif %}
{% endfor %}
</ul>
</div>
{% for shelf in suggested_books %}
{% with shelf_counter=forloop.counter %}
{% for book in shelf.books %}
<div class="suggested-tabs card{% if shelf_counter != 1 or not forloop.first %} hidden{% endif %}" role="tabpanel" id="book-{{ book.id }}">
<div class="card-header">
<p class="card-header-title">
<span>{% include 'snippets/book_titleby.html' with book=book %}</span>
</p>
<div class="card-header-icon is-hidden-tablet">
{% include 'snippets/toggle/toggle_button.html' with label="close" controls_text="book" controls_uid=book.id class="delete" nonbutton=True pressed=True %}
</div>
<div class="tab-group">
<div class="tabs is-small">
<ul role="tablist">
{% for shelf in suggested_books %}
{% if shelf.books %}
{% with shelf_counter=forloop.counter %}
<li>
<p>
{{ shelf.name }}
</p>
<div class="tabs is-small is-toggle">
<ul>
{% for book in shelf.books %}
<li{% if shelf_counter == 1 and forloop.first %} class="is-active"{% endif %}>
<a href="#book-{{ book.id }}" id="tab-book-{{ book.id }}" role="tab" aria-label="{{ book.title }}" aria-selected="{% if shelf_counter == 1 and forloop.first %}true{% else %}false{% endif %}" aria-controls="book-{{ book.id }}">
{% include 'snippets/book_cover.html' with book=book size="medium" %}
</a>
</li>
{% endfor %}
</ul>
</div>
</li>
{% endwith %}
{% endif %}
{% endfor %}
</ul>
</div>
<div class="card-content">
{% for shelf in suggested_books %}
{% with shelf_counter=forloop.counter %}
{% for book in shelf.books %}
<div class="suggested-tabs card" role="tabpanel" id="book-{{ book.id }}"{% if shelf_counter != 1 or not forloop.first %} hidden{% endif %} aria-labelledby="tab-book-{{ book.id }}">
<div class="card-header">
<p class="card-header-title">
<span>{% include 'snippets/book_titleby.html' with book=book %}</span>
</p>
<div class="card-header-icon is-hidden-tablet">
{% include 'snippets/toggle/toggle_button.html' with label="close" controls_text="book" controls_uid=book.id class="delete" nonbutton=True pressed=True %}
</div>
</div>
<div class="card-content">
{% include 'snippets/shelve_button/shelve_button.html' with book=book %}
{% active_shelf book as active_shelf %}
{% if active_shelf.shelf.identifier == 'reading' and book.latest_readthrough %}
{% include 'snippets/progress_update.html' with readthrough=book.latest_readthrough %}
{% endif %}
{% include 'snippets/create_status.html' with book=book %}
</div>
</div>
{% endfor %}
{% endwith %}
{% endfor %}
</div>
{% endfor %}
{% endwith %}
{% endfor %}
{% endif %}
{% if goal %}

View file

@ -1,7 +1,7 @@
{% load bookwyrm_tags %}
<div class="cover-container is-{{ size }}">
{% if book.cover %}
<img class="book-cover" src="/images/{{ book.cover }}" alt="{{ book.alt_text }}" title="{{ book.alt_text }}">
<img class="book-cover" src="/images/{{ book.cover }}" alt="{{ book.alt_text }}">
{% else %}
<div class="no-cover book-cover">
<img class="book-cover" src="/static/images/no_cover.jpg" alt="No cover">

View file

@ -2,34 +2,36 @@
{% load i18n %}
{% load bookwyrm_tags %}
<div class="tabs is-boxed">
<ul role="tablist">
<li class="tab-change is-active" data-category="tab-option-{{ book.id }}" role="tab" aria-selected="true" tabindex="0" data-tab="review-{{ book.id }}">
<a>{% trans "Review" %}</a>
</li>
<li class="tab-change" data-category="tab-option-{{ book.id }}" role="tab" tabindex="0" data-tab="comment-{{ book.id}}">
<a>{% trans "Comment" %}</a>
</li>
<li class="tab-change" data-category="tab-option-{{ book.id }}" role="tab" tabindex="0" data-tab="quote-{{ book.id }}">
<a>{% trans "Quote" %}</a>
</li>
</ul>
</div>
<div class="tab-group">
<div class="tabs is-boxed" role="tablist">
<ul>
<li class="is-active">
<a href="#review-{{ book.id }}" id="tab-review-{{ book.id }}" role="tab" aria-selected="true" aria-controls="review-{{ book.id }}" data-category="tab-option-{{ book.id }}">{% trans "Review" %}</a>
</li>
<li>
<a href="#comment-{{ book.id}}" id="tab-comment-{{ book.id }}" role="tab" aria-selected="false" aria-controls="comment-{{ book.id}}" data-category="tab-option-{{ book.id }}">{% trans "Comment" %}</a>
</li>
<li>
<a href="#quote-{{ book.id }}" id="tab-quote-{{ book.id }}" role="tab" aria-selected="false" aria-controls="quote-{{ book.id }}" data-category="tab-option-{{ book.id }}">{% trans "Quote" %}</a>
</li>
</ul>
</div>
<div class="tab-option-{{ book.id }}" id="review-{{ book.id }}">
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type='review' %}
{% endwith %}
</div>
<div class="tab-option-{{ book.id }}" id="review-{{ book.id }}" role="tabpanel" aria-labelledby="tab-review-{{ book.id }}">
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type='review' %}
{% endwith %}
</div>
<div class="hidden tab-option-{{ book.id }}" id="comment-{{ book.id }}">
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type="comment" placeholder="Some thoughts on '"|add:book.title|add:"'" %}
{% endwith %}
</div>
<div class="tab-option-{{ book.id }}" id="comment-{{ book.id }}" role="tabpanel" aria-labelledby="tab-comment-{{ book.id }}" hidden>
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type="comment" placeholder="Some thoughts on '"|add:book.title|add:"'" %}
{% endwith %}
</div>
<div class="hidden tab-option-{{ book.id }}" id="quote-{{ book.id }}">
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type="quotation" placeholder="An excerpt from '"|add:book.title|add:"'" %}
{% endwith %}
<div class="tab-option-{{ book.id }}" id="quote-{{ book.id }}" role="tabpanel" aria-labelledby="tab-quote-{{ book.id }}" hidden>
{% with 0|uuid as uuid %}
{% include 'snippets/create_status_form.html' with type="quotation" placeholder="An excerpt from '"|add:book.title|add:"'" %}
{% endwith %}
</div>
</div>

View file

@ -16,13 +16,13 @@
{% block panel %}
<div class="block columns">
<div class="column">
<div class="tabs" role="tablist">
<div class="tabs">
<ul>
{% for shelf_tab in shelves %}
<li class="{% if shelf_tab.identifier == shelf.identifier %}is-active{% endif %}">
<a href="/user/{{ user | username }}/shelf/{{ shelf_tab.identifier }}" role="tab" aria-selected="{% if shelf_tab.identifier == shelf.identifier %}true{% else %}false{% endif %}">{{ shelf_tab.name }}</a>
{% for shelf_tab in shelves %}
<li class="{% if shelf_tab.identifier == shelf.identifier %}is-active{% endif %}">
<a href="/user/{{ user | username }}/shelf/{{ shelf_tab.identifier }}"{% if shelf_tab.identifier == shelf.identifier %} aria-current="page"{% endif %}>{{ shelf_tab.name }}</a>
</li>
{% endfor %}
{% endfor %}
</ul>
</div>
</div>