iOS offers extensive accessibility features for users with vision loss, hearing loss, and other disabilities. Most UIKit-based apps can be made accessible with very little effort, allowing more people to use your app while providing an equally engaging experience for all.
iOS给弱视，弱听，和有其他障碍的用户提供了大量可用特性。几乎基于UIKit框架的应用都能轻而易举的使用，让更多的人使用你的应用同时为大家提供同样有吸引力的体验。
Reduce Transparency 降低透明度
VoiceOver 语音播报
Button Shapes 按钮形状
Play 开始
Provide alternative text labels for images, icons, and interface elements.Alternative text labels aren’t visible onscreen, but they let VoiceOver audibly describe what's onscreen, making navigation easier for people with visual impairments.
给图片，图标，和界面元素提供代替文本标签。替代的文本标签在界面上不可见，但会语音提示界面上有什么，让视觉缺陷的用户可以容易导航。
Respond to accessibility preferences.If your app uses UIKit to implement its user interface, text and interface elements automatically adapt to certain accessibility preferences, such as bold and larger text. Your app should also check and respond to accessibility preferences when appropriate, such as when the option to reduce motion is enabled. Apps implementing custom fonts should attempt to match the accessibility behavior of the system fonts.
响应可访问设置，如果你的应用使用UIKit框架实现用户界面，文本和界面元素自动的采用特定的辅助功能，例如更大字体和粗体文本。你的应用应该会适时的检查和响应辅助功能设置，如减弱动态效果的选项已启用， 应用实现定制字体应该尝试匹配系统字体的可访问设置。
Test your app with accessibility features.In addition to text and motion changes, accessibility options can change contrast, invert colors, reduce transparency, and more. Enable these settings and observe how your app will look and behave for people who enable these features.
测试你应用的可访问特性。除了文本和动效改变，可访问选项能调节对比度，反转颜色，降低透明度等等。启用这些设置，为启用这些特性的用户观察你的应用看起来使用起来怎么样。
Include closed captions and audio descriptions.Closed captions allow the deaf and hard-of-hearing to perceive spoken dialogue and other audible content in videos. Audio descriptions provide spoken narration of important video content for the visually impaired.
引入隐藏式字幕和口述影像。隐藏式字幕允许失聪和听力障碍的用户以视频的形式感知口语对话或其它音频内容。口述影像为视觉受损的用户提供重要内容的语音描述。
For more information, seeiOS AccessibilityandAccessibility Programming Guide for iOS.
更多信息参阅 iOS Accessibility 和 Accessibility Programming Guide for iOS 文章。
