Kotlin + Rx：需要消费者，找到 KFunction

Question

我正在使用 Kotlin + Retrofit + Rx。我想将其中一个请求提取到函数中：

fun getDataAsync(onSuccess: Consumer<Data>, onError: Consumer<in Throwable>) {
    ApiManager.instance.api
            .getData("some", "parameters", "here")
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(Consumer {
                time = System.currentTimeMillis()
                onSuccess.accept(it)
            }, onError)
}


fun onButtonClick() {
    getDataAsync(this::onSuccess, this::onError)
}

private fun onSuccess(data: Data) {}

private fun onError(throwable: Throwable) {}

我在行 getDataAsync(this::onSuccess, this::onError):

中遇到错误

Type mismatch: inferred type is KFunction1<@ParameterName Data, Unit> but Consumer<Data> was expected

Type mismatch: inferred type is KFunction1<@ParameterName Throwable, Unit> but Consumer<in Throwable> was expected

如何解决？

Answer 1

您可以传递一个函数，而不是将消费者作为参数传递

fun getDataAsync(onSuccess: (Data) -> Unit, onError: (Throwable) -> Unit) {
     ApiManager.instance.api
        .getData("some", "parameters", "here")
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe({
            time = System.currentTimeMillis()
            onSuccess(it)
        }, onError)
}


fun onButtonClick() {
   getDataAsync(this::onSuccess, this::onError)
}

private fun onSuccess(data: Data) {}

private fun onError(throwable: Throwable) {}

Answer 2

问题是您的方法 getDataAsync 需要一个类型为 Consumer 的对象作为两个参数，而您提供的是方法引用。请注意，同样的错误发生在 Java.

为了解决它，您可以将 getDataAsync 的两个参数都声明为函数引用，或者创建 Consumer.

的实现

第一个解决方案

fun getDataAsync(onSuccess: (Data) -> Unit, onError: (Throwable) -> Unit) {

}

fun onButtonClick() {
    getDataAsync(::onSuccess, ::onError)
}


private fun onSuccess(data: Data) {

}

private fun onError(throwable: Throwable) {}

第二种解决方案

fun getDataAsync(onSuccess: Consumer<Data>, onError: Consumer<in Throwable>) {

}

fun onButtonClick() {
    getDataAsync(Consumer { data ->
        // do something
    }, Consumer { throwable ->
        // do something
    })
}