Accessibility features and best practices
The BlackBerry 10 OS allows you to implement accessibility improvements. Here's a list of features in the BlackBerry 10 OS that can be used to create more accessible apps.
Screen Reader. This app reads all of the UI elements and actions in your app's UI out loud. You must set each element's accessibility property so the screen reader can properly identify the element or action, and read it out loud.
The BlackBerry 10 OS screen reader can be enabled on the device under Settings > Accessibility > Screen Reader.
Accessibility API. You can use the functionality found in the AbstractA11yObject API to add a human-readable name to your app's UI controls to make them more accessible. Every accessible control should have human-readable text associated with it. In most cases, this can be inferred by the text being displayed on the control or by the text of a label that is labeling the control. However, with icon-only push buttons, the name cannot be inferred and must be supplied by you through the accessibility property, or in the case of an image, through its alt text property. The properties in the AbstractA11yObject class allow you to provide information that's used by the screen reader to read UI elements out loud.
BlackBerry 10 OS provides a magnifier capability that allows users to increase or decrease the magnification of the screen. You should view your app using the magnifier to be certain that it can be navigated as expected when magnified. This accessibility feature can be enabled (or disabled) on the device under Settings > Accessibility > Magnify Mode.
Closed Captions (CC). The media owner must provide an .scc (Scenarist Closed Caption) file, which contains the Closed Captioned data, to add Closed Captioning to video content. There are two formats that can be used with CC media. The first format is mpeg2ts, which is a broadcast standard and has CC embedded in it. The second format is SMTP-TT, which uses a separate file for the CC content. Closed Captioned content can be enabled or disabled, however there is no way to know what languages are available for the CC content. A media content owner who chooses to use the SMPT-TT format can include an additional file per language. Therefore, the user can enable the service for a specific language, such as English (En), French (Fr), Spanish (Es) and other languages that are available for that content.
The creation and use of .scc files to provide Closed Captioned content requires the use of third party software. Another option for creating .scc files is to use one of the many Closed Captioning services available. In either case, the media content owner is responsible for creating and embedding the Closed Captioning data into their video media content if they wish to provide Closed Captions for their content.
Display settings. Display settings can be configured to make colors, text, and other items easier to view.
TTY settings. TTY settings are available for users who want to use a teletypewriter with their BlackBerry 10 OS device.
For more information about Closed Captions, see Wikipedia: Closed Captioning.
How accessible is your app?
The following questions can help you measure your app's current level of accessibility.
- Does your UI adapt well when the font size preferences are set in the Settings > Display > Font Size dropdown control?
- Can your UI be easily navigated when magnified, or when large font sizes are used?
- Are the UI elements large enough, and spaced out far enough to allow users to easily operate them using only their thumb?
- Are there any actions, or information that can only be accessed through the use of color? For example, are there any instructions that say something like "click the Red button"?
- Is the information in your UI laid out in a logical sequence when viewed as a screen reader would view it?
- Have you set the above accessibility property for all UI elements and actions so your app's UI can be properly read by a screen reader?
- When human readable text for a control has not been provided or cannot be determined, are the UI control elements (such as buttons, sliders, tabs, check boxes, etc.) in your app described correctly using the accessibility properties found in AbstractA11yObject?
- Are the input fields laid out in a logical sequence as well? If they are, then you should be able to use your app using only a screen reader and without looking at the screen. Can your app be used without your having to look at the UI, and only with a screen reader?
Design your UI to be accessible
Follow these recommendations and best practices to create accessible UI designs: Accessibility: Best Practices.
Last modified: 2013-12-20