JavaFx：滑块 - 带颜色的双向移动

Question

背景：

我正在尝试在 JavaFx 的 TableView 中创建实时股票走势的视觉表示，如 2 个附加图像（绿色表示正，琥珀色负 & 值在左下角的日低点，值在右下角的日高点）。运动将由实时数据流控制。因此，如果滑动标记超过当天的开盘价，则需要能够随着颜色变化双向滑动

研究：

我总是提到这个很棒的 -> Link 但在这种情况下寻求指导，因为我不确定它是否适用于 Progress Bar 或 Slider。

如能就此提出任何建议，我们将不胜感激。

Answer 1

一个可能的解决方案是将两个 ProgressBar 打包成一个 HBox。
以下不应被视为完整的实现，而是作为想法的演示：

import javafx.application.Application;
import javafx.beans.binding.DoubleBinding;
import javafx.beans.binding.When;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
import src.tests.BiDiProgressBar.Indicator;

public class BiDiProgressBar extends Application {

    @Override public void start(Stage stage) {

        final HBox indicator = new Indicator(60);
        stage.setScene(new Scene(indicator));
        stage.show();

        //run test
        Thread th = new Thread(new TestTask((Indicator)indicator));
        th.setDaemon(true);
        th.start();
    }


    class Indicator extends HBox{

        //properties representing indicator min max, mid and current values
        DoubleProperty minValue = new SimpleDoubleProperty(0);
        DoubleProperty maxValue = new SimpleDoubleProperty(100);
        DoubleProperty nominalValue = new SimpleDoubleProperty(50);
        DoubleProperty currentlValue;

        //properties representing full, neg and pos ranges
        DoubleProperty rangeValue = new SimpleDoubleProperty();
        DoubleProperty posRangeValue = new SimpleDoubleProperty();
        DoubleProperty negRangeValue = new SimpleDoubleProperty();

        private ProgressBar negProgBar, posProgBar;
        private static final double indicatorWidth = 200; //in pixles

        Indicator(double nomlValue){

            super(0);
            setNominalValue(nomlValue);
            rangeValue.bind(maxValue.subtract(minValue));
            negRangeValue.bind(nominalValue.subtract(minValue));
            posRangeValue.bind(rangeValue.subtract(negRangeValue));
            currentlValue = new SimpleDoubleProperty(nominalValue.get());

            negProgBar = new ProgressBar();
            negProgBar.rotateProperty().set(180); //rotate to progress from left to right

            posProgBar = new ProgressBar();
            setProgBarWidth();
            setProgBarValue();
            getChildren().addAll(negProgBar, posProgBar);

            getStylesheets().add(getClass().getResource("css/indicator.css").toExternalForm());
            negProgBar.getStyleClass().add("neg-bar");
            posProgBar.getStyleClass().add("pos-bar");
        }

        private void setNominalValue(double nominalValue) {
            nominalValue = withInRange(nominalValue);
            this.nominalValue.set(nominalValue);
        }

        private void setProgBarWidth() {
            double width = (indicatorWidth * nominalValue.get())/rangeValue.get();
            negProgBar.setPrefWidth(width);
            posProgBar.setPrefWidth(indicatorWidth-width);
        }

        private void setProgBarValue() {

            final DoubleBinding posBinding = new When(currentlValue.greaterThan(nominalValue))
                        .then((currentlValue.subtract(nominalValue)).divide(posRangeValue))
                        .otherwise(0.);
            final DoubleBinding negBinding = new When(currentlValue.lessThan(nominalValue))
                    .then((nominalValue.subtract(currentlValue)).divide(negRangeValue))
                    .otherwise(0.);
            posProgBar.progressProperty().bind(posBinding);
            negProgBar.progressProperty().bind(negBinding);
        }

        private double withInRange(double value) {
            value = (value < minValue.get()) ? minValue.get() : value;
            value = (value > maxValue.get()) ? maxValue.get() : value;
            return value ;
        }

        public double getMin() {return minValue.get();}

        public double getMax() {return maxValue.get();}

        public double getNominal() {return nominalValue.get();}

        public void setProgress(double value) {
            currentlValue.set(withInRange(value));
        }
    }

    public static void main(String[] args) { launch(args);}
}

class TestTask extends Task<Void>{

    private Indicator indicator;
    public TestTask(Indicator indicator) {
        this.indicator = indicator;
    }

    @Override
    protected Void call() throws Exception {

        for(double value = indicator.getNominal();
                value < (indicator.getMax() +5) ; //exceed max
                value++)    {
            indicator.setProgress(value);
            delay(100);
        }

        for(double value = indicator.getMax();
                value > (indicator.getMin() -5 ) ;  value--)    {
            indicator.setProgress(value);
            delay(100);
        }

        return null;
    }

    private void delay(long millis) {

        try {
            Thread.sleep(millis);
        } catch (InterruptedException ex) { ex.printStackTrace();   }
    }
}

结果如下所示：

两者ProgressBar相交的点代表日开始值。在最终实施中，在任何给定时间只有一个进度条处于活动状态。

indicator.css

.root { -fx-background-color: black; -fx-padding: 15; }
.progress-bar > .track {
  -fx-text-box-border: white;
  -fx-control-inner-background: lightgrey;
  -fx-border-radius: 0px ;
  -fx-background-radius: 0px ;
}

.pos-bar  { -fx-accent: green; }
.neg-bar  { -fx-accent: red; }

Answer 2

您可以使用滑块或进度条相当简单地完成此操作，使用 CSS 更改轨道的背景颜色。对于进度条，只需将进度条设为透明即可。

基本思路是使用线性"gradient"。如果起始值为x%，当前值为y%，加上y > x，你需要颜色停止在

(default 0%, default x%, green x%, green y%, default y%, default 100%)

其中 default 是默认背景颜色。（与红色替换绿色类似，如果 y < x 则 x 和 y 切换。）

这是一个 SSCCE：

import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.control.Slider;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class BidirectionalSlider extends Application {

    @Override
    public void start(Stage primaryStage) {
        double startingValue = 0.5 ;
        Slider slider = new Slider(0, 1, startingValue);

        slider.styleProperty().bind(Bindings.createStringBinding(() -> {

            double min = slider.getMin();
            double max = slider.getMax();
            double value = slider.getValue() ;

            return createSliderStyle(startingValue, min, max, value);

        }, slider.valueProperty()));

        ProgressBar progressBar1 = new ProgressBar(0.1);
        ProgressBar progressBar2 = new ProgressBar(0.9);

        progressBar1.styleProperty().bind(Bindings.createStringBinding(() -> 
            createSliderStyle(startingValue, 0.0, 1.0, progressBar1.getProgress()), 
            progressBar1.progressProperty()));

        progressBar2.styleProperty().bind(Bindings.createStringBinding(() -> 
            createSliderStyle(startingValue, 0.0, 1.0, progressBar2.getProgress()), 
            progressBar2.progressProperty()));

        VBox root = new VBox(5, slider, progressBar1, progressBar2);
        root.setAlignment(Pos.CENTER);

        Scene scene = new Scene(root, 400, 400);
        scene.getStylesheets().add("style.css");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private String createSliderStyle(double startingValue, double min, double max, double value) {
        StringBuilder gradient = new StringBuilder("-slider-track-color: ");
        String defaultBG = "derive(-fx-control-inner-background, -5%) " ;
        gradient.append("linear-gradient(to right, ").append(defaultBG).append("0%, ") ;

        double valuePercent = 100.0 * (value - min) / (max - min);

        double startingValuePercent = startingValue * 100.0;


        if (valuePercent > startingValuePercent) {
            gradient.append(defaultBG).append(startingValuePercent).append("%, ");
            gradient.append("green ").append(startingValuePercent).append("%, ");
            gradient.append("green ").append(valuePercent).append("%, ");
            gradient.append(defaultBG).append(valuePercent).append("%, ");
            gradient.append(defaultBG).append("100%); ");
        } else {
            gradient.append(defaultBG).append(valuePercent).append("%, ");
            gradient.append("red ").append(valuePercent).append("%, ");
            gradient.append("red ").append(startingValuePercent).append("%, ");
            gradient.append(defaultBG).append(startingValuePercent).append("%, ");
            gradient.append(defaultBG).append("100%); ");               
        }
        return gradient.toString() ;
    }

    public static void main(String[] args) {
        launch(args);
    }
}

和基础 CSS 文件 (style.css):

.slider, .progress-bar {
    -slider-track-color: derive(-fx-control-inner-background, -5%) ;
}

.slider .track, .progress-bar .track {
    -fx-background-color: 
        -fx-shadow-highlight-color,
        linear-gradient(to bottom, derive(-fx-text-box-border, -10%), -fx-text-box-border),
        -slider-track-color ;
}

.progress-bar .bar {
    -fx-background-color: transparent ;
}

JavaFx：滑块 - 带颜色的双向移动

JavaFx: Slider - Bidirectional movement with color

java

css

javafx

javafx-8

javafx-2