See the recommendations here.
The most important is TalkBack which is a pre-installed screen reader service provided by Google. It uses spoken feedback to describe the results of actions such as launching an app, and events such as notifications.
You should include the following in your xml layout files to describe all ImageViews, ImageButtons and all Checkboxes:
<ImageView android:contentDescription="@string/origin_label"/>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