What are the main reasons that can lead to ANR errors in applications?

ANR (Application Not Responding) errors occur when the application does not respond to user actions within a certain period of time (usually 5 seconds for the main thread). The main causes are:

• Performing long operations (such as network requests, database reads, complex calculations) on the main (UI) thread.
• Locks or deadlocks that prevent the main thread from processing events.
• Improper thread management, where heavy work is not offloaded to background threads.

To avoid ANR, long operations should be moved to separate threads or asynchronous methods should be used.