Coroutines中未捕获异常

Question

我的viewmodel用它的作用域启动coroutine

class MyViewModel(private var myUseCase: MyUseCase) : ViewModel() {
    private val viewModelJob = Job()
    private val uiScope = CoroutineScope(Dispatchers.Main + viewModelJob)

    fun doSomething() {
        uiScope.launch {
            try {
                myUseCase()
            } catch (exception: Exception) {
                // Do error handling here
            }
        }
    }
}

我的usecase只处理一些逻辑，在本例中是某种验证器

class MyUseCase(private val myRepository: MyRepository) {
    suspend operator fun invoke() {
        if (checker()) {
            throw CustomException("Checker Failed due to: ...")
        }

        myRepository.doSomething()
    }
}

然后我的存储库只处理网络层/本地层

object MyRepository {
    private val api = ... // Retrofit

    suspend fun doSomething() = api.doSomething()
}

interface MyInterface {
    @POST
    suspend fun doSomething()
}

以下是我得到的错误日志：

com.example.myapp.domain.errors.CustomException
        at com.example.myapp.domain.FeatureOne$invoke$2.invokeSuspend(FeatureOne.kt:34)
        at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
        at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:238)
        at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:594)
        at kotlinx.coroutines.scheduling.CoroutineScheduler.access$runSafely(CoroutineScheduler.kt:60)
        at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:742)

错误直接指向显式的throw语句。

Answer 1

尝试使用CoroutineExceptionHandler可以解决在Coroutines中处理异常的问题。

CoroutineExceptionHandler上下文元素用作coroutine的泛型catch块，在这里可以进行自定义日志记录或异常处理。这类似于使用thread.uncaughtExceptionHandler。

怎么用？

val handler = CoroutineExceptionHandler { _, exception -> 
    println("Caught $exception") 
}
val job = GlobalScope.launch(handler) {
    throw AssertionError()
}
val deferred = GlobalScope.async(handler) {
    throw ArithmeticException() // Nothing will be printed, relying on user to call 
    deferred.await()
}
joinAll(job, deferred)