ANR: Application Not Responding

Definition: Occurs when a mobile application’s UI (main) thread is blocked for too long (typically 5 seconds for input events or longer for broadcast receivers/services), causing the app to freeze and often resulting in a system dialog prompting the user to close the app

How to Calculate: Often tracked as an ANR Rate

ANR Rate: $ \text{ANR Rate} = (\text{Number of Unique Users who Experienced an ANR} / \text{Total Daily Active Users}) \times 100%$

Specific ANR types (e.g., User-Perceived ANR Rate) are often tracked by platform consoles like Google Play Console.

Note: ANRs don’t always result in a crash, but they severely impact user experience