Question

我有一个想要在文本字段中显示的复杂对象。使用stringBinding可以正常工作。但是我不知道如何使其双向转换，以使文本字段可编辑。

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)
    }
}

运行此命令时，plainString是可编辑的，并且看到标签更改，因为所做的编辑又回到了属性中。

如何编写自定义处理程序，或者需要使用什么类来使stringBinding读取和写入？我浏览了很多“属性”和“绑定”文档，但看不到任何明显的内容。

Answer 1

Ta-Da

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)
    }
}

我仅通过返回null来对转换器进行编辑，以对“帐户”进行无效输入。这只是一个简单的创可贴解决方案，它不会强制输入正确的内容，但是会拒绝在属性中放置错误的值。

Answer 2

这可以更干净地完成。我敢打赌，这种额外财产周围有办法。该示例非常脆弱，因为为了保持简单而不进行输入检查。但这可以证明解决方案：

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)
    }
}

如何将自定义属性双向绑定到文本字段？

2 个答案: