Why cant a thread that is not the UI thread access the view?

Question

I know that no thread can access the current view unless it is the UI Thread. I am wondering why? Why does it matter which thread is changing the view? Is it a security reason?

Answer 1

Android application uses Single Thread Model and this thread is responsible to dispatch various events to the UI elements. This single thread model has two rules :

1. Do not block the UI thread
2. Do not access the Android UI toolkit from outside the UI thread

If you create a thread that uses View outside the UI thread then it violates the second rules.