Verifying accessibility features for iOS apps

Original:verifying App accessibility on IOS

Translator: Liu Hui, Li Hongli ( China information Barrier-free Product Alliance & Information Barrier-free society )

1. About verifying accessibility features on iOS

IMPORTANT: This document contains preliminary information about an API or technology used in the development process. This information may change at any time, and the software implemented under the document should be tested in the final operating system software.

So far, developers have done a barrier-free optimization. But how to ensure the accessibility characteristics of the application? Developers can use the same screen reading technology as the visually impaired user to interact with the app to test the accessibility features of the application. This way, developers can replicate a barrier-free experience. When you personally experience the accessibility of your application, developers may consider the accessibility features of enhanced applications. If you have done a barrier-free optimization, now come and experience it for yourself.

Read on to learn how to verify that the barrier-free features are enhanced as expected.

1.1 Overview

Developers can test the app's accessibility features on real-world devices and in the iOS simulator.

1.1.1 Learn how to use voiceover

iOS Native screen reading technology is called voiceover. With increased usability for visually impaired users, voiceover has changed the way the system clicks and sweeps are interpreted. Because voiceover controls devices in a non-traditional way, learning how to use voiceover looks very difficult. But learning to use voiceover is focused on learning the right gestures and several usability techniques.

Related chapters: Use voiceover on your device to test accessibility features

1.1.2 Learn how to use the barrier-free checker

The Barrier-free Checker (accessibility Inspector) is a handy tool to help developers test for defective, barrier-free implementations. The Accessibility Checker runs on your Mac's built-in iOS emulator. After you open the inspector, the developer can see all the available information that voiceover uses.

Related chapters: Using the Accessibility Checker in the iOS simulator to debug accessibility features

1.2 Prerequisites for increased availability of visually impaired users

This document assumes that the developer has tried to perform a barrier-free optimization based on the following documents:

• iOS barrier-free Programming Guide-Describes how custom views enhance accessibility features.
• Support Accessibility in the iOS View Controller Programming Guide-Describes the view controller role that makes the application accessible.

1.3 More

Hello bye: Use the Accessibility API to increase the user base--Download the sample code project to see the accessibility implementation in action.

2. Use voiceover on your device to test accessibility features

Using voiceover to test your app is a good idea so that developers can experience the app in the same way as voiceover users. Using voiceover to manipulate apps can expose problematic areas-for example, confusing tags, useless hints, unreachable elements-all of which make the application a hindrance.

VoiceOver is a complex technology that provides a number of powerful features for users with disabilities. Although developers don't need to be voiceover expert users with voiceover test apps, they still need to know some simple basic gestures. This section describes how to activate voiceover and use it to manipulate the app.

2.1 First Step

Go to "settings, general-purpose, barrier-free->voiceover" and click on the switch to open voiceover,1-1 as shown. If you are prompted for a barrier-free element in your app, developers need to make sure that the "read-out prompt (Speak Hints)" switch is turned on (default on). Make sure that the speech rate slider (Speaking rates Slider) has a suitable value before leaving voiceover settings.

Figure 1-1 Opening voiceover in SettingsNote: Alternatively, you can use the Quick Click home button to open voiceover, which is described in the "three hit home key to quickly open voiceover".

When voiceover is turned on, the tester will notice that many familiar gestures have different effects. For example, click Let voiceover read out the selected item, and double-click to activate the selected item. When an element is selected, voiceover draws a black rounded rectangle around the element, which is called the voiceover cursor. VoiceOver users can confidently navigate the interface, because the voiceover cursor prevents users from accidentally triggering certain events.

Table 1-1 describes all voiceover gestures in detail.

Table 1-1 voiceover gestures differ from standard gestures

VoiceOver gestures	Behavior
Drag on the screen	Select and read each item of the touch.
Single-Finger click	Read out the selected item.
Single finger left and right sweep	Select the next or previous item. The order of elements is determined by the layout coordinates on the screen, from left to right, top to bottom. You can override this order by using the Shouldgroupaccessibilitychildren property to group the accessibility attributes together.
Single finger up and down sweep motion	Increase or decrease the value on an adjustable element, such as a slider. An adjustable element implements the Uiaccessibilitytraitadjustable feature. In text view, move the insertion point forward or backward.
Single-finger double-tap	This action achieves the following effects: Activates the selected item; switch is selected; Unlocks the screen when the unlock switch is selected.
split tap -touch and hold on one element, then tap other points on the screen with other fingers.	Merge the selected and active gestures into the same. Once familiar, this gesture can be entered quickly, especially when typing.
Single-finger double-tap long press -one fingers, double click, click on the second, continue long press the screen, do not lift.	Drag an item.
Two-Finger click	Interrupted reading. Double-click again to continue reading.
double-fingered double-tap-also known as Magic click.	Opens or stops the current behavior. For example, the magic tap can pause the stopwatch timing of the clock app, and answer calls that hold the call app. Not all views have a magical click. The user must choose to implement the feature. See Responding to special voiceover gestures.
two finger rub --a zigzag gesture, also known as exit.	Returns the parent level. For example, an exit gesture can be rolled back in the navigation controller to eject the navigation stack. Not all views implement an exit gesture. See Responding to special voiceover gestures.
Double pointing up sweep	Start reading all accessibility items from the top of the screen.
Double pointing down sweep	Read all accessibility items starting at the current location.
Two fingers pinch to open	Select the text.
Two fingers kneading off	Uncheck the text.
Swipe up and down with three fingers	Scrolls the list or area on the screen.
Three fingers left and right sweep	Navigate to the next or previous page.
three-finger double-click -If the zoom function is activated, the gesture becomes a three-finger three-click.	Switch Voice. If the device is not muted, voiceover voice identification, or audio feedback continues to function.
three-finger three-click -If the zoom function is activated, the gesture becomes a three-finger four-click.	Toggle the screen blinds. See "Simulating the voiceover experience with a screen curtain."
Four fingers click the top or bottom of the screen	Select the first or last barrier-free element on the screen.

Tip : There is a voiceover practice area where you can practice voiceover gestures in settings, general-purpose, barrier-free->voiceover. The practice button will not appear until voiceover is activated.

When testing the application, ensure that interactive controls and important information entries can be accessed by the voiceover cursor. UI decorations are independent of voiceover users and do not need to be accessible.

important : To avoid the interface sounds like a robot, try to carve the text without obstacles. Guidelines for creating accessible tags and tips, see providing accurate and useful property information

2.2 VoiceOver tips and tricks

This section contains specific voiceover shortcuts and gestures to help users manipulate and manage voiceover. Using these tips, you can quickly change the voiceover settings to jump to specific elements when there are many elements on the screen, using iOS from the perspective of the visually impaired user.

2.2.1 Using three-click home button to quickly switch voiceover

You can quickly switch the voiceover,1-2 as shown by setting it in the "settings, general-purpose, barrier-free, three-click". You can then turn voiceover on and off with the three hit home key. This is a lot faster than using the switch to navigate to the settings app each time, greatly improving the efficiency of the barrier-free test, and when unsure whether the gesture is correct, you can simply turn off voiceover.

Figure 1-2 setting voiceover three hit home key activation

2.2.2 Fine-tuning speech granularity with voiceover rotor

You can use the voiceover rotor to decompose voiceover speech into a single word or even a single character, as shown in 1-3. Two fingers rotate clockwise or counterclockwise, like turning a dial to circulate the rotor option. Once an option is selected, a single finger swipe up and down to get the previous or next value, depending on the selected rotor option.

Figure 1-3 using the voiceover rotor to read text verbatim

You can also add options to the rotor in the "settings--general-purpose, barrier-free->voiceover-> rotor". For example, add speech speed and adjust speech speed by swiping up or down anywhere in iOS. The rotor option is context sensitive and may not appear in all environments.

2.2.3 using the project selector to quickly scroll

The project selector helps users quickly select the element they are looking for, especially when there are a large number of elements in the view. Using the two-finger three-click screen, trigger the item selector, 1-4, and then select the index list on the right, up and down blows to get the previous or next letter. This method is useful when you need to jump to a specific point in the desktop view without an indexed list. When there is no search area on the screen, it is useful to search for items and organize non-alphabetical lists. Use the exit gesture to cancel the item selector-a two-finger zigzag gesture.

Figure 1-4 Project Selector

2.3 Simulating the voiceover experience with a screen curtain

Using the app's visually impaired user experience, testers can use the voiceover screen blinds appropriately. When the screen curtain is activated, voiceover turns off the device display, causing no one to read the content on the screen. Turn off screen display testing, requiring testers to rely on voiceover to read aloud information and remove the temptation for visual users to use the app. When using voiceover, the three-finger three-click screen turns off the screen display. Turn on the screen display and perform the same operation again.

Note: If zoom is activated, the screen curtain gesture becomes a three-finger four-click.

3. Debugging barrier-free performance with the Accessibility Checker in the iOS simulator

The Barrier-free Checker (accessibility Inspector) shows accessibility information for each barrier-free element in the application. Developers can use the Accessibility Checker to simulate the interaction of voiceover and accessibility elements in the app, and debug the information provided by accessibility elements.

Note: The Accessibility Checker can help developers debug your app's barrier-free performance during development, but this test is not a substitute for using voiceover to test your app on a real device. One thing to note is that the barrier-free checker does not read out the accessibility information, so the tester cannot hear the reading of the element description. Although the barrier-free checker is the ideal tool for quickly verifying that an element provides the right accessibility information, developers should test the app on real-world devices, turn on voiceover, and make sure the app runs the way users expect it to. See Using voiceover on your device to test accessibility performance.

The barrier-free checker runs in the iOS simulator, allowing testers to simply see the accessibility tags, values, hints (if applied), features, and frame combinations for each element on the screen. Testers can also see a list of recently sent accessibility notifications.

To start the barrier-free checker:

1. Run the app in the iOS simulator (for more information, see the Demo User Guide).

2. In the simulated device environment, press the home key to return to the home screen.

3. Open "Settings--general--accessibility".

4. Open the Barrier-free checker switch. The barrier-free checker remains active until it is closed, regardless of the developer exiting or restarting the iOS emulator.

When running an app in the iOS emulator, click Simulate click, use mouse scrolling, keyboard emulation blows, or single finger drag. However, when the Accessibility Checker is activated, click the focus inspector to an element, and the inspector does not simulate clicking on the element. When the Accessibility Checker is activated, click on the element to simulate, double-clicking the element. When the Barrier checker focuses on an element, a shaded rectangle (similar to the voiceover cursor) is drawn around the element, as shown in 2-1.

Figure 2-1 Barrier Checker draws a shaded rectangle around the selection element

In order to be able to scroll, you must first invalidate the Barrier checker. Use your mouse to drag and drop the scroll to the desired position, reactivate the Barrier Checker, and click the close control in the upper-left corner of the panel (the closing control looks like a ring with an X number). Clicking on this control does not really close the barrier checker; turn off the inspector and need to go to the universal-accessibility-accessibility Checker to change the switch settings.

When the Barrier checker is not activated, 2-2 shows no effect on how to interact with any of the simulated app features in the iOS simulator.

Figure 2-2 Accessibility Checker does not activate the interface

4. Document Revision History

This table describes the changes to the document.

Date	Matters
2013-04-23	The new document describes how to ensure that an iOS app can be used by voiceover users.

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Verifying accessibility features for iOS apps