问题
We have a web-based app which uses a side-by-side experience for desktop users where the left side of the screen is a file browser and editor and the right side of the screen is an interactive preview. Users of our app will make constant and iterative changes on the left and and then interact with the preview on the right, switching back and forth many times in quick succession.
Is there a "best practice" for allowing quick and easy navigation between these two interactive areas? I know this might fall under the "opinion" category, but I feel that accessibility is such an overlooked topic that it helps to have as many resources as possible.
回答1:
You have a few tools at your disposal.
Headings
Headings are one of the easiest ways to bake in some super simple section switching. Screen reader users will use the keys 1 through 6 to navigate by heading levels so if both of your panels are <h2>s (for example) they can simply cycle location using headings.
Keyboard shortcut keys
You can set keyboard shortcut keys.
However you should never do this in isolation. By this I mean if you say that switching window is say Alt + 0 you must allow users to be able to change these key bindings to their preferences.
This is so your shortcut keys don't interfere with their screen reader keys (as they may have set custom keyboard shortcuts).
please note: as pointed out in the comments this is not a WCAG requirement for key combinations (which is only for single keys) but is a usability best practice and highly encouraged, especially as some screen reader users use a modifier key rather than a toggle key for screen reader navigation.
Then we get into an interesting area which I like to illustrate by saying "how would a one handed user use your page?".
This example makes you realise that some sort of sticky keys solution may also be considered where key combinations can be done with a sequence of keys, any time apart (as you may have someone with NO HANDS using eye gaze technology or a switch for example so you don't want to impose a time limit.)
Obviously the above are extreme examples but things you may want to consider (and in reality anyone using eye gaze would be able to visually switch panels etc.)
Voice commands
Being able to switch panels via voice (for example Dragon Naturally Speaking) is also essential.
Now you can do key combinations with voice software so that fixes most issues but they can be annoying and fiddly.
One thing that is quick to use on most voice software is clicking any button on a page with a unique name.
As such having a button above each panel that activates it would be beneficial to voice users.
Assuming these buttons have unique names I could simply say "click activate panel 2" (where "activate panel 2" is the button name) and switch immediately.
Do you need to manage focus?
Bear in mind that when you switch panels you will by default start at the top each time.
This may be exactly what you want but more than likely this would be a terrible user experience.
Instead you may want to remember the previous focus location. Then if I use the keyboard shortcut it would jump back to the same location in the panel. If I use the voice / button click to change location same again.
However if someone uses headings to navigate this obviously wouldn't work. You could then give them a button directly after the heading that says "resume from previous location" to fix this and use that to manage focus.
User settings
As you can see there are loads of things that different people with different requirements may or may not need.
As such adding all of the features by default would probably make the application worse to use for majority of users.
Instead have a settings screen that lets a user turn on features that benefit them, set their own shortcut keys, turn on or off sticky keys, decide if they want you to manage focus for them (or not) etc.
回答2:
This is a difficult problem! I have been giving a similar issue a lot of thought. I have outlined one idea that uses ARIA live regions, and an alternative idea that might work better if quick-jump keyboard support is vital.
- Live region announcements as part of a
<form>
The <output> tag may be what you're looking for. It is mapped to the ARIA role of status so any changes to its content will be announced without any focus change. That way, the user can continue to navigate and make changes on the left side without always having to flip over to the right side to know what changes were made.
The role status has an implicit aria-live value of "polite", so that the announcement will wait until any other descriptive announcement is finished.
It has an implicit aria-atomic value of "true", which means that any change will trigger the announcement of the entire contents of the element -- which may or may not be appropriate for the content. If not, add aria-atomic="false" to read out only the changed node.
If the content inside the <output> could be anything other than phrasing content (including <div>s or heading tags) then you should use a <div> with the role attribute of "status" instead.
Custom keyboard controls can get tricky with various types of assistive technology (AT) software/hardware. Plus those commands probably can't be made easily discoverable. Some ATs provide a keyboard command to flip between a controlling element and the element assigned via its aria-controls attribute. Unfortunately, this functionality is poorly supported, but it is the current standard, so support may get better over time. Currently only NVDA on Windows supports it, with the keyboard command Insert + Alt + M.
Adding aria-controls to an element controlling an <output>/status is mandatory anyway, so give it a unique id attribute and set that as the value of aria-controls on each form element inside the <form>.
If the <output>/status is wrapped in a <fieldset> and the inputs are all wrapped in a containing <fieldset>, then each <fieldset> acts as a grouping container, so the user can navigate between them quickly. As part of this, ensure the <fieldset> containing the <output> directly follows <fieldset> containing the form elements in the source order. If this isn't possible, add the aria-owns attribute to the containing <form> and reference the id attributes of both <fieldset>s with a space in between.
- Always-open non-modal
<dialog>
You may instead consider making the right side pane an always-open non-modal <dialog>. A <button> next to each interactive element on the left pane would move focus to the <dialog>, and the Escape key would return focus back to the <button>. Focus isn't trapped within a non-modal <dialog>, so the user can still move between each pane using normal navigation methods. The <dialog> needs to have an open attribute to appear and it also needs to have aria-modal="false".
Each <button> would need an aria-controls value referencing the <dialog>'s id attribute, and an aria-haspopup value of "dialog". The <button>s could be invisible until focused.
回答3:
There's only a single focused point at any given time. So there isn't any real miracle solution, screen reader and other keyboard-only users will necessarily have to repeatedly go back and forth.
IN fact, the most important isn't to be able to switch quickly between the different parts (you must only somehow give a way to do it only with keyboard), but to not lose cursor position when you switch. For example if I edit something on the left, go to the right to check the result, and then go back to the left side, I expect to find the insertion point exactly where I left it off. You really have to make sure that this is always correct, and as closest as possible when changes occurs (especially when it's asynchronous, i.e. a change occurs on the right side when you are on the left side).
The most similar accessibility recipe or component is probably split view. In windows world, the most used shortcuts for cycling between the different splitte parts is F6, and Shift+F6 to cycle in reverse direction.
Don't hesitate to add other easier or additional shortcuts if the switch has to be really frequent, such as Ctrl+Tab, if such shortcuts aren't already used for something else. F6 and Shift+F6 aren't the easiest shortcuts to perform, especially on laptops where all F1-12 keys may not be available at all or only by using an additional FN key. I personally always found F6 a questionnable choice, but that's only an opinion; at least we have something and that's of course better than nothing.
However, don't replace an existing shortcut commonly used. (for example Ctrl+Tab = switch between different tabs, don't use it for cycling between views if there are tabs in your application and keep it for the tabs)
来源：https://stackoverflow.com/questions/64993332/accessibility-provide-mechanism-for-easy-navigation-between-interactive-sectio