对于数字输入,将模拟控件同步到文本显示有时会很方便。在此Swing example中,JSpinnerJSlider分别监听更改事件,并分别更新对方的模型以进行匹配。如下所示,一个类似的JavaFX程序连接了 Spinner Slider ,这些监听器使控件保持协调:

slider.valueProperty().addListener((Observable o) -> {
    spinner.getValueFactory().setValue(slider.getValue());
});
spinner.valueProperty().addListener((Observable o) -> {
    slider.setValue((double) spinner.getValue());
});

不幸的是,当我在微调器的StringConverter中添加SpinnerValueFactory时,初始值是未格式化的,直到更改了任何一个控件为止-即使在添加转换器后再次显式设置初始值时:
spinner.getValueFactory().setConverter(…);
spinner.getValueFactory().setValue(INITIAL_VALUE);

我要去哪里错了?

java - 连接具有StringConverter的Slider和Spinner-LMLPHP
import java.text.NumberFormat;
import javafx.application.Application;
import javafx.beans.Observable;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Slider;
import javafx.scene.control.Spinner;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;
import javafx.util.converter.PercentageStringConverter;

/**
 * @see https://stackoverflow.com/a/6067986/230513
 */
public class SpinSlider extends Application {

    private static final double MIN = 0;
    private static final double MAX = 1;
    private static final double INITIAL_VALUE = 0.5;
    private static final double STEP_INCREMENT = 0.1;

    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("SpinSlider");
        Slider slider = new Slider(MIN, MAX, INITIAL_VALUE);
        slider.setBlockIncrement(STEP_INCREMENT);
        Spinner spinner = new Spinner(MIN, MAX, INITIAL_VALUE, STEP_INCREMENT);
        spinner.getValueFactory().setConverter(
            new PercentageStringConverter(NumberFormat.getPercentInstance()));
        spinner.getValueFactory().setValue(INITIAL_VALUE);
        slider.valueProperty().addListener((Observable o) -> {
            spinner.getValueFactory().setValue(slider.getValue());
        });
        spinner.valueProperty().addListener((Observable o) -> {
            slider.setValue((double) spinner.getValue());
        });
        GridPane root = new GridPane();
        root.addRow(0, slider, spinner);
        root.setPadding(new Insets(8, 8, 8, 8));
        root.setHgap(8);
        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

}

最佳答案

首先将INITIAL_VALUE用作微调框的构造函数的initialValue参数。在内部,微调器的具体 SpinnerValueFactory DoubleSpinnerValueFactory,在其ChangeListener属性中添加了value;当再次设置初始值时,该值实际上并没有改变。有两种方法可以证明自己:

  • 为构造函数指定一个不同的值,并在添加转换器后设置所需的值:
    Spinner spinner = new Spinner(MIN, MAX, -42, STEP_INCREMENT);
    spinner.getValueFactory().setConverter(…);
    spinner.getValueFactory().setValue(INITIAL_VALUE);
    
  • 使用所需的初始值构造一个SpinnerValueFactory,并使用它来构造微调器:
    SpinnerValueFactory factory = new SpinnerValueFactory
        .DoubleSpinnerValueFactory(MIN, MAX, INITIAL_VALUE, STEP_INCREMENT);
    factory.setConverter(…);
    Spinner spinner = new Spinner(factory);
    

  • 此外,下面的示例用双向绑定(bind)替换了两个监听器,该双向绑定(bind)使用弱监听器来允许垃圾回收属性:
    slider.valueProperty().bindBidirectional(
        spinner.getValueFactory().valueProperty());
    

    平凡的是,微调器和滑块可以相互控制。更常见的是,每个人都可以在控制另一个模型拥有的属性(property)的过程中保持同步:
    model.xProperty().bindBidirectional(slider.valueProperty());
    model.xProperty().bindBidirectional(spinner.getValueFactory().valueProperty());
    

    java - 连接具有StringConverter的Slider和Spinner-LMLPHP
    import java.text.NumberFormat;
    import javafx.application.Application;
    import javafx.geometry.Insets;
    import javafx.scene.Scene;
    import javafx.scene.control.Slider;
    import javafx.scene.control.Spinner;
    import javafx.scene.control.SpinnerValueFactory;
    import javafx.scene.layout.GridPane;
    import javafx.stage.Stage;
    import javafx.util.converter.PercentageStringConverter;
    
    /**
     * @see https://stackoverflow.com/a/55427307/230513
     * @see https://stackoverflow.com/a/6067986/230513
     */
    public class SpinSlider extends Application {
    
        private static final double MIN = 0;
        private static final double MAX = 1;
        private static final double INITIAL_VALUE = 0.5;
        private static final double STEP_INCREMENT = 0.1;
    
        @Override
        public void start(Stage primaryStage) {
            primaryStage.setTitle("SpinSlider");
            Slider slider = new Slider(MIN, MAX, INITIAL_VALUE);
            slider.setBlockIncrement(STEP_INCREMENT);
            SpinnerValueFactory factory = new SpinnerValueFactory
                .DoubleSpinnerValueFactory(MIN, MAX, INITIAL_VALUE, STEP_INCREMENT);
            factory.setConverter(new PercentageStringConverter(
                NumberFormat.getPercentInstance()));
            Spinner spinner = new Spinner(factory);
            slider.valueProperty().bindBidirectional(spinner.getValueFactory().valueProperty());
            GridPane root = new GridPane();
            root.addRow(0, slider, spinner);
            root.setPadding(new Insets(8, 8, 8, 8));
            root.setHgap(8);
            Scene scene = new Scene(root);
            primaryStage.setScene(scene);
            primaryStage.show();
        }
    
        public static void main(String[] args) {
            launch(args);
        }
    
    }
    

    09-26 12:31