Why is it recommended to perform all user interface operations in a single thread?

In Android, all operations with the user interface (UI) must be performed on a single thread — the main (UI) thread — because the UI itself is not thread-safe.

Attempting to update UI elements from another thread can lead to unpredictable behavior, crashes, or exceptions.

Main reasons:

• UI components are not synchronized for multi-threaded operation.
• Ensuring the consistency and integrity of the interface state.
• Simplifying the programming model and preventing data races.

Therefore, long-running operations (such as data loading or calculations) are performed in a background thread, and UI updates are done through callback mechanisms or special methods that switch to the UI thread.