如何在不阻塞线程的情况下从挂起 function 返回值

Question

I have a suspend method: checkIfAvailable() that returns a Boolean. I want to get that boolean value and then use it in my activity. I try this the following way(not sure if this is how it should be done):

suspend fun checkIfAvailable(year: Int): Boolean = viewModelScope.async{
        return@async dao.checkIfAvailable(year)
    }.await()

This returns a boolean. The problem is that i can't use that boolean, because the function must be a suspend function as await() must be called inside one.

How do i get the boolean value without blocking the main thread ?

I tried it with runBlocking in my activity:

fun something(tag: Int): Boolean {
            return runBlocking {
            return@runBlocking checkIfAvailable(tag)
        }
}

but this crashes or blocks the mainthread.

I just need a way to get the value out of the suspend function and into a variable without blocking the thread.

Answer 1

Use this inside your activity:

lifecycleScope.launch(Dispatchers.Default) {
      val result = checkIfAvailable(year)
}