Developers Many Android users have different abilities that require them to interact with their Android devices in different ways. These include users who have visual, physical or age-related limitations that prevent them from fully seeing or using a touchscreen, and users with hearing loss who may not be able to perceive audible information and alerts.
很多Android用户因能力差异，需要使用不同的方式与Android设备进行交互。视觉障碍、肢体残疾和与年龄有关的障碍用户，不能充分的看到或使用触摸屏，还有听力障碍用户因听力损失而无法获取音频信息和警报。
Android provides accessibility features and services for helping these users navigate their devices more easily, including text-to-speech, haptic feedback, gesture navigation, trackball and directional-pad navigation. Android application developers can take advantage of these services to make their applications more accessible.
Android提供了无障碍特性和服务，帮助这些用户更轻松地浏览他们的设备，包括文本转语音、触觉反馈、手势导航、轨迹球和定向垫导航。 Android应用程序开发者可以利用这些服务，使他们的应用程序更加无障碍。
Android developers can also build their own accessibility services, which can provide enhanced usability features such as audio prompting, physical feedback, and alternative navigation modes. Accessibility services can provide these enhancements for all applications, a set of applications or just a single app.
Android开发者还可以建立自己的无障碍服务，提供更强的可用性特性，如音频提示、物理反馈以及替代导航方式。无障碍服务可以为所有应用、一组应用或单一的app提供这些增强特性。
The following topics show you how to use the Android framework to make applications more accessible.
以下主题展示了如何使用Android框架，使应用程序更加无障碍：
- Making Applications Accessible
- Development practices and API features to ensure your application is accessible to users with disabilities.
- Accessibility Developer Checklist
- A checklist to help developers ensure that their applications are accessible.
- Building Accessibility Services
- How to use API features to build services that make other applications more accessible for users.