在Android上取代Kotlin Coroutine的回调

Question

How can I replace my callbacks with coroutine? It's possible? I tried to replace my onclick event of adapter item using suspendCoroutine:

suspend fun waitForButtonClick() = suspendCoroutine<String> { continuation ->
    button.setOnClickListener {
        continuation.resume("My Data")
    }
}

And on activity:

GlobalScope.launch {
  val callbackResult = adapter.waitForButtonClick()
}

The problem is that I can call waitForButtonClick only one time, because resume can be executed only one time. How to replace the onClickCallback with Kotlin coroutine?

Answer 1

the problem is that calling setOnClickListener overwrites the old listener.

you can use something like this to collect the suspended functions:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    button.setOnClickListener(this::resumeSuspendedClickFunctions)
}

private val suspendedClickFunctions = LinkedList<View.OnClickListener>()

private fun resumeSuspendedClickFunctions(view: View){
    suspendedClickFunctions.forEach {
        it.onClick(view)
    }
    suspendedClickFunctions.clear()
}

suspend fun waitForButtonClick() = suspendCoroutine<String> { continuation ->
    val listener = View.OnClickListener {
        continuation.resume("My Data")
    }
    suspendedClickFunctions.add(listener)
}