android - 从 Firebase 监听器发出状态 - Kotlin Flow

Question

我想使用 Kotlin Flow 来处理 FirebaseAuth 状态。我知道下面的代码是错误的，但我不知道如何修复它。我尝试使用 channelFlow 并且当我想要 send 或 offer

时它总是崩溃

   fun registerFlow(email: String, password: String) = flow {
    emit(AuthState.Loading)
    firebaseAuth.createUserWithEmailAndPassword(email, password)
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                CoroutineScope(Dispatchers.IO).launch {      
                    emit(AuthState.Success(task.result?.user))
            } }else {
                  emit(AuthState.Error(task.exception))
            }
        }
}

}

Listener里面的协程抛出

z E/AndroidRuntime: FATAL EXCEPTION: DefaultDispatcher-worker-1
Process: pl.rybson.musicquiz, PID: 26578
java.lang.IllegalStateException: Flow invariant is violated:
        Emission from another coroutine is detected.
        Child of StandaloneCoroutine{Active}@4903a45, expected child of StandaloneCoroutine{Completed}@988059a.
        FlowCollector is not thread-safe and concurrent emissions are prohibited.
        To mitigate this restriction please use 'channelFlow' builder instead of 'flow'

我使用send()时的错误

FATAL EXCEPTION: DefaultDispatcher-worker-1
Process: pl.rybson.musicquiz, PID: 27105
kotlinx.coroutines.channels.ClosedSendChannelException: Channel was closed

Answer 1

当代码块运行完成时，流程结束。

您可以使用 integration 而不是使用回调使其成为暂停功能。

fun registerFlow(email: String, password: String) = flow {
    emit(AuthState.Loading)
    val result = firebaseAuth.createUserWithEmailAndPassword(email, password).await()
    if (result.isSuccessful) {     
        emit(AuthState.Success(result.result?.user))
    } else {
        emit(AuthState.Error(result.exception))
    }
}