Updating GUI: Runnables vs Messages

Question

To update the GUI from other threads, there are basically two main approaches:

1. Use java.lang.Runnable with any of these methods:

   Activity.r         
   
   
           

Answer 1

I prefer Runnable to Message. I think code using Runnable is much clearer than Message, because the event handling code is very close to the event. Also, You can avoid the overhead of defining constants and switch cases.

And I don't think using Runnable violates encapsulation. You can extract the code in Runnable.run() into another method in the outer class, for example on...Event(), or even wrap it into an EventHandler object. Both ways are much clearer than using Message, especially when you need store references in Message, because using Runnable avoids downcasting msg.obj. And the nameless field msg.obj is also error prone and sometimes inefficient to understand.

And Runnable can also be reused by storing it as a field.