Question

请注意，我使用的是javafx库。以下是通过空间移动的类船的功能。玩家点击船只，出现一个下拉菜单，点击“移动”后，一个协程开始\ moveJob \调用函数\ move（）\，这将使对象开始向目的地移动。

问题在于，如果我再次单击“移动”，中途航行，那么对象将表现不正常，因为两个协同程序将同时运行并更新对象的x和y坐标。

因此我需要取消\ moveJob \每次我点击“移动”并开始一个新目的地的新协程。我还没想出如何使用\ movingJob.cancel（）\ preemptively来说，以防有一个协程已经运行。

item1.setOnAction {

        println("Something...")
        root.onMouseClicked = EventHandler { event ->
            launch {
                println("Clicked on an object.")
            }
            /* If you click on an object, you don't want scene.onMouseClicked
                to be executed. event.consume() gobbles the event so that it isn't passed
                down.
             */
            event.consume()
            // Here we should have something that reaches
            root.onMouseClicked = null
            scene.onMouseClicked = null
        }
        scene.onMouseClicked = EventHandler { event ->
            val moveJob =launch {
                move(event, root)
            }
            root.onMouseClicked = null
            scene.onMouseClicked = null
        }

        /* Move to coorindates that the user clicks next */
    }

Answer 1

在班级的某处声明Job变量

private var currentJob: Job? = null

并使用以下代码

item1.setOnAction {
    println("Something...")
    root.onMouseClicked = EventHandler { event ->
        currentJob?.cancel()
        currentJob = launch {
            println("Clicked on an object.")
        }
        /* If you click on an object, you don't want scene.onMouseClicked
            to be executed. event.consume() gobbles the event so that it isn't passed
            down.
         */
        event.consume()
        // Here we should have something that reaches
        root.onMouseClicked = null
        scene.onMouseClicked = null
    }
    scene.onMouseClicked = EventHandler { event ->
        currentJob?.cancel()
        currentJob = launch {
            move(event, root)
        }
        root.onMouseClicked = null
        scene.onMouseClicked = null
    }

    /* Move to coorindates that the user clicks next */
}

取消正在运行的协同程序，并在Kotlin中每次单击鼠标时启动一个新程序。

1 个答案: