tornadofx監聽鼠標事件，用鼠標畫點

import javafx.collections.FXCollections
import javafx.scene.input.*
import javafx.scene.paint.Color
import javafx.scene.shape.Circle
import tornadofx.*

class LearnApp : App(LearnV::class)
class LearnV : View("learn") {
    val dots = mutableListOf<Circle>()
    val count = stringProperty()

    override val root = borderpane {
        top = toolbar {
            Buttons.values().forEach { ss ->
                button(ss.toString().replace("_", " ")) {
                    action {
                        ss.run()
                    }
                    useMaxWidth = true
                }
            }
        }
        center = pane {

            Dot.all.onChange {
                children.removeAll(dots)
                dots.clear()

                it.list.forEach {
                    Circle(it.x, it.y, 5.0).apply {
                        fill = Color.RED
                        children += this
                        dots += this
                    }
                }
                count.value = dots.size.toString()
            }
            addEventHandler(MouseEvent.MOUSE_CLICKED) {
                Dot.create(it.x, it.y)
                count.value = dots.size.toString()
            }
        }
        bottom {
            form {
                fieldset {
                    field("Dots created:") {
                        label(count)
                    }
                }
            }
        }
        prefWidth = 200.0
        prefHeight = 200.0
    }
}

enum class Buttons {
    Clear {
        override fun run() {
            Dot.all.clear()
        }
    },
    Add {
        override fun run() {
            val dot = Dot.create((1..200).random().toDouble(), (1..200).random().toDouble())
        }

    };

    abstract fun run()
}

class Dot(val id: Int, val x: Double, val y: Double) {
    companion object {
        val all = FXCollections.observableArrayList<Dot>()
        fun create(x: Double, y: Double): Dot {

            val nextId = (all.asSequence().map { it.id }.max() ?: -1) + 1

            return Dot(nextId, x, y).also { all += it }
        }
    }
}