滑块拇指中的 JavaFX 值

Question

我在这里有一个滑块，它在滑块拇指上显示一个数字。每当我拖动滑块时，数字都会增加或减少。我希望拇指显示整数而不是双精度。

import javafx.application.Application;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class SliderWithLabeledThumb extends Application {
    public void start(Stage ps) {
        Slider s = new Slider();

        StackPane root = new StackPane(s);
        root.setPadding(new Insets(5));
        s.setOrientation(Orientation.VERTICAL);
        s.setMin(49);
        s.setMax(99);
        s.setValue(51);
        s.setMinorTickCount(0);
        s.setMajorTickUnit(1);

        Scene scene = new Scene(root);

        s.applyCss();
        s.layout();
        Pane p = (Pane) s.lookup(".thumb");
        Label l = new Label();
        l.textProperty().bind(s.valueProperty().asString("%.1f").concat(" °"));

        p.getChildren().add(l);

        ps.setScene(scene);
        ps.show();
    }

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

当我将 asString() 的参数从“%.1f”更改为“%d”时，出现异常

l.textProperty().bind(s.valueProperty().asString("%d").concat(" °"));

错误信息：

Exception in Application start method
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.IllegalFormatConversionException: d != java.lang.Double
    at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4302)
    at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2793)
    at java.util.Formatter$FormatSpecifier.print(Formatter.java:2747)
    at java.util.Formatter.format(Formatter.java:2520)
    at java.util.Formatter.format(Formatter.java:2455)
    at java.lang.String.format(String.java:2940)
    at com.sun.javafx.binding.StringFormatter$4.computeValue(StringFormatter.java:196)
    at javafx.beans.binding.StringBinding.get(StringBinding.java:152)
    at com.sun.javafx.binding.StringFormatter.format(StringFormatter.java:207)
    at javafx.beans.binding.Bindings.format(Bindings.java:4846)
    at javafx.beans.binding.NumberExpressionBase.asString(NumberExpressionBase.java:319)
    at embeddedwebview.SliderWithLabeledThumb.start(SliderWithLabeledThumb.java:29)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)

这是我的 CSS 文件：

.slider .track {
    -fx-pref-height: 10px;
    -fx-pref-width: 20px;
}

.slider .thumb {
    -fx-pref-height: 30;
    -fx-prefer-width: 30;
}

目前的输出：

Answer 1

这个问题最终几乎是重复的：

• Problem with System.out.printf command in Java

所以你不能使用%d来格式化一个double值，你必须使用%f。如果您只想显示双精度值的整数部分，您可以让%.0f（如 Hypnic Jerk 在 cmets 中推荐的那样）进行四舍五入到零小数位（不会显示小数点）。根据formatting javadoc，使用round half up algorithm。

import javafx.application.Application;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class SliderWithLabeledThumb extends Application {
    public void start(Stage ps) {
        Slider s = new Slider();

        StackPane root = new StackPane(s);
        root.setPadding(new Insets(5));
        s.setOrientation(Orientation.VERTICAL);
        s.setMin(49);
        s.setMax(99);
        s.setValue(51);
        s.setMinorTickCount(0);
        s.setMajorTickUnit(1);

        Scene scene = new Scene(root);

        s.applyCss();
        s.layout();
        Pane p = (Pane) s.lookup(".thumb");
        Label l = new Label();
        l.textProperty().bind(s.valueProperty().asString("%.0f").concat(" °"));

        p.getChildren().add(l);

        ps.setScene(scene);
        ps.show();
    }

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