AccessibilityNodeInfo

AccessibilityNodeInfo is a class in the Android accessibility framework. It represents a node in the accessibility tree, which is a hierarchical structure of UI elements visible on the screen. Each AccessibilityNodeInfo object encapsulates information about a single UI element, such as its text, content description, type, state, and actions it can perform.

Accessibility services use AccessibilityNodeInfo to understand the user interface and interact with it on behalf of users with disabilities. For example, a screen reader service might traverse the accessibility tree, reading out the text and descriptions of each AccessibilityNodeInfo to provide auditory feedback. Similarly, an input control service could use this information to perform actions like clicking a button or checking a checkbox.

Developers can create and populate AccessibilityNodeInfo objects when implementing custom views or widgets to ensure they are accessible. This involves overriding methods like `createAccessibilityNodeInfo` to return a correctly populated node for the view. The information provided within an AccessibilityNodeInfo is crucial for making Android applications usable by a wider range of users, including those who rely on assistive technologies.