如果最后一次操作以异常结束，Kotlin协程会立即给出异常

Question

When I was try to login on my service via retrofit. When my service is off, 10 seconds after clicking the button I got an SocketTimeoutException exception. So far everything is normal but again, I clicked the button again after the error gave the same error immediately. What's wrong?

interface LoginService {

    @FormUrlEncoded
    @POST("/login")
    fun login(@Field("id") id: String, @Field("pw") pw: String): Deferred<Response<User>>

}

class LoginViewModel : ViewModel() {

    private var job: Job = Job()
    private val scope: CoroutineScope = CoroutineScope(Dispatchers.Main + job)
    private val service by lazy { RetrofitApiFactory().create(LoginService::class.java) }
    private val excHandler = CoroutineExceptionHandler { _, throwable ->
        Timber.e(throwable);
    }

    fun doLogin(id: String, pw: String) {
        scope.launch(excHandler) {
            val response = service.login(id, pw).await()
            if (response.isSuccessful) {
                response.body()
                        ?.let { user -> doOnSuccess(user) }
                        ?: doOnError(InvalidUserException())
            } else doOnError(Exception())
        }
    }

    private fun CoroutineScope.doOnError(e: Throwable) {
        excHandler.handleException(coroutineContext, e)
    }

    private fun doOnSuccess(user: User) {
        ...
    }

    override fun onCleared() {
        job.cancel()
    }

}

Answer 1

You need to change your CoroutineScope to not re-use the same Job . It's already considered as failed , so it will not even begin executing.

See related issue on github .