* The article source is from Udacity Nanodegree Program- Become an Android Developer *

Accessibility refers to the design of products, devices, services, or environments for people who experience disabilities. Android provides accessibility features like

• TalkBack: It uses spoken feedback to describe the results of actions such as launching an app, and events such as notifications.
• Explore by Touch which is a system feature that works with TalkBack, allowing you to touch your device’s screen and hear what’s under your finger via spoken feedback. This feature is helpful to users with low vision.
• Accessibility settings that let you modify your device’s display and sound options, such as increasing the text size, changing the speed at which text is spoken, and more. and more.

Describe user interface controls

contentDescription attribute to describe what any view actually presents, this description text is not displayed anywhere on the screen, but if the user enables accessibility services that provide audible prompts, then when the user navigates to that control, the text is spoken.

<ImageView android:contentDescription="@string/origin_label"/>

ContentDescription is just one of many things you need to consider when building your app for accessibility, others include:

• Enable focus-based navigation which makes sure users can navigate your screen layouts using external hardware like bluetooth keyboards.
• No audio-only feedback which guarantees any audio feedback to always have a secondary feedback mechanism to support users who are deaf or hard of hearing
  For the full check list and best practices follow this link: Accessibility Developer Checklist