如何将自定义属性双向绑定到文本字段？

Question

我有一个复杂的对象，我想在文本字段中显示。这与 stringBinding 一起工作正常。但我不知道如何使它成为双向的，以便文本字段是可编辑的。

package com.example.demo.view

import javafx.beans.property.SimpleObjectProperty
import javafx.beans.property.SimpleStringProperty
import tornadofx.*

class MainView : View("Hello TornadoFX") {
    val complexThing: Int = 1
    val complexProperty = SimpleObjectProperty<Int>(complexThing)

    val complexString = complexProperty.stringBinding { complexProperty.toString() }

    val plainString = "asdf"
    val plainProperty = SimpleStringProperty(plainString)

    override val root = vbox {
        textfield(complexString)
        label(plainProperty)
        textfield(plainProperty)
    }
}

当我运行这样做时，plainString 是可编辑的，我看到标签发生变化，因为编辑将返回到属性。

我如何编写自定义处理程序或者我需要使用什么class来使 stringBinding 被读取和写入？我查看了很多属性和绑定文档，但没有看到任何明显的内容。

Answer 1

这或许可以做得更干净。我敢打赌有办法绕过额外的属性。该示例很脆弱，因为为了保持简单，它没有进行输入检查。但它可以证明解决方案：

class Point(x: Int, y: Int) {
    val x: Int = x
    val y: Int = y
}

class PointConverter: StringConverter<Point?>() {
    override fun fromString(string: String?): Point? {
        val xy = string?.split(",")
        return Point(xy[0].toInt(), xy[1].toInt())
    }

    override fun toString(point: Point?): String {
        return "${point?.x},${point?.y}"
    }
}

class MainView : View("Hello TornadoFX") {
    val point = Point(5, 6)
    val pointProperty = SimpleObjectProperty<Point>(point)
    val pointDisplayProperty = SimpleStringProperty()
    val pointStringProperty = SimpleStringProperty()
    val pc = PointConverter()

    init {
        pointDisplayProperty.set(pc.toString(pointProperty.value))
        pointStringProperty.set(pc.toString(pointProperty.value))
        pointStringProperty.addListener { observable, oldValue, newValue ->
            pointProperty.set(pc.fromString(newValue))
            pointDisplayProperty.set(pc.toString(pointProperty.value))
        }
    }

    override val root = vbox {
        label(pointDisplayProperty)
        textfield(pointStringProperty)
    }
}

Answer 2

他-达

class Point(val x: Int, val y: Int) //You can put properties in constructor

class PointConverter: StringConverter<Point?>() {
    override fun fromString(string: String?): Point? {
        if(string.isNullOrBlank()) return null //Empty strings aren't valid
        val xy = string.split(",", limit = 2) //Only using 2 coordinate values so max is 2
        if(xy.size < 2) return null //Min values is also 2
        val x = xy[0].trim().toIntOrNull() //Trim white space, try to convert
        val y = xy[1].trim().toIntOrNull()
        return if(x == null || y == null) null //If either conversion fails, count as invalid
        else Point(x, y)
    }

    override fun toString(point: Point?): String {
        return "${point?.x},${point?.y}"
    }
}

class MainView : View("Hello TornadoFX") {
    val point = Point(5, 6) //Probably doesn't need to be its own member
    val pointProperty = SimpleObjectProperty<Point>(point)
    val pc = PointConverter()

    override val root = vbox {
        label(pointProperty, converter = pc) //Avoid extra properties, put converter in construction
        textfield(pointProperty, pc)
    }
}

我将您的转换器编辑为 "account" 以通过仅返回 null 进行无效输入。这只是一个简单的创可贴解决方案，不会强制输入正确的内容，但它会拒绝在您的属性.

中输入错误的值

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