HandlerThread replacement in Coroutines

Question

I have some code which uses single HandlerThread with Handler to send messages to it. Is there any way to do this with coroutines? I don't want to create new coroutine every time, I just want to execute blocks of code on the HandlerThread. Please help

Answer 1

If you are looking to execute a block of code in the main Android thread, then you can use UI context from kotlinx-coroutines-android module like this:

launch(UI) { 
    ... // this block of code will be executed in main thread
}

The above snippet sends a message to the main handler to execute your code.

If you looking for a custom handler thread for background work, then you can create a single-threaded context in one of two ways.

Generic approach: Use newSingleThreadedContext() like this:

val ctx = newSingleThreadedContext() // define your context

launch(ctx) { ... } // use it to submit your code there

Android-specific approach: Create new Android Handler, use Handler.asCoroutineDispatcher() extension to convert it to the coroutines context extension. Then you'll be able to use launch to send your blocks of code for execution.