协程不开始吗?

时间:2019-12-19 15:48:53

标签: android higher-order-functions kotlin-coroutines coroutinescope androidx-lifecycle

基于此post throttleFirst函数:

fun <T> throttleFirst(
    skipMs: Long = 700L,
    scope: CoroutineScope = viewModelScope,
    action: (T) -> Unit
): (T) -> Unit {
    var throttleJob: Job? = null
    return { param: T ->
        if (throttleJob?.isCompleted != false) {
            throttleJob = coroutineScope.launch {
                destinationFunction(param)
                delay(skipMs)
            }
        }
    }
}

我正在这样使用它:

查看

<Button
    android:onClick="@{viewModel.myClickListener}"
.../>

ViewModel:

fun myClickListener() = View.OnClickListener { _ ->
    throttleClick(clickAction = {
        //do things
    })
}

BaseViewModel

protected fun throttleClick(millis: Long = 700L, clickAction: (Unit) -> Unit): (Unit) -> Unit  {
    throttleFirst(millis, scope = viewModelScope, action = clickAction)
}

但没有任何反应,没有达到 clickAction 。在调试过程中,逐步操作在遇到return { param: T ->时结束,并且永不调用返回函数(throttleJob?.isCompleted ...代码)。
我在做什么错了?

编辑,在Patrick的帮助下,最终的解决方案是:

ViewModel

private val myThrottleClick = throttleClick(clickAction = {
    //do things
})

fun myClickListener() = View.OnClickListener { myThrottleClick(Unit) }

BaseViewModel

protected fun throttleClick(millis: Long = 700L, clickAction: (Unit) -> Unit): (Unit) -> Unit {
    return throttleFirst(millis, action = clickAction)
}

1 个答案:

答案 0 :(得分:1)

您的throttleFirst函数会构成一个点击监听器,因此您必须将其存储在点击监听器范围之外的val中。即

val clickListener = throttleFirst { doStuff() }

fun myClickListener() = View.OnClickListener { _ -> clickListener() }

您也许可以完全取消使用myClickListener函数,而只需在xml中引用clickListener

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