连接具有StringConverter的Slider和Spinner [英] Connecting a Slider and Spinner that has a StringConverter
问题描述
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 示例中，一个JSpinner和JSlider分别监听更改事件，并分别更新对方的模型匹配.如下所示，一个类似的JavaFX程序将 Spinner 和 Slider ，并且这些侦听器可以使控件保持协调一致:
For numeric input, it's sometimes convenient to synchronize an analog control to a text display. In this Swing example, a JSpinner and a JSlider each listen for change events, and each updates the other's model to match. A similar JavaFX program, shown below, connects a Spinner and a Slider, and these listeners keep the controls coordinated:
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SpinnerValueFactory中添加StringConverter时，初始值是未格式化的，直到更改了任何一个控件为止-即使在再次明确设置初始值的情况下，在之后添加了转换器:
Unfortunately, when I added a StringConverter to the spinner's SpinnerValueFactory, the initial value was unformatted until either control was changed—even when setting the initial value explicitly again, after adding the converter:
spinner.getValueFactory().setConverter(…);
spinner.getValueFactory().setValue(INITIAL_VALUE);
我要去哪里错了?
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);
}
}
推荐答案
您的INITIAL_VALUE首先用作微调器的构造函数的initialValue参数.在内部，微调器的具体 SpinnerValueFactory 是在其value属性中添加ChangeListener的DoubleSpinnerValueFactory；当再次设置初始值时，该值实际上并没有更改.有两种方法可以说明自己:
Your INITIAL_VALUE is first used as the initialValue parameter to the spinner's constructor. Internally, the spinner's concrete SpinnerValueFactory is a DoubleSpinnerValueFactory that adds a ChangeListener to its value property; when the initial value is set again, the value hasn't really changed. Two approaches suggest themselves:
-
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:
Specify a different value to the constructor and set the desired one after adding the converter:
Spinner spinner = new Spinner(MIN, MAX, -42, STEP_INCREMENT);
spinner.getValueFactory().setConverter(…);
spinner.getValueFactory().setValue(INITIAL_VALUE);
构造具有所需初始值的SpinnerValueFactory并将其用于构造微调器:
Construct a SpinnerValueFactory with the desired initial value and use it to construct the spinner:
SpinnerValueFactory factory = new SpinnerValueFactory
.DoubleSpinnerValueFactory(MIN, MAX, INITIAL_VALUE, STEP_INCREMENT);
factory.setConverter(…);
Spinner spinner = new Spinner(factory);
此外，下面的示例将两个侦听器替换为双向绑定，该双向绑定使用弱侦听器允许垃圾回收属性:
In addition, the example below replaces the two listeners with a bidirectional binding, which uses weak listeners to allow garbage collection of properties:
slider.valueProperty().bindBidirectional(
spinner.getValueFactory().valueProperty());
微调器和滑块可以相互控制.更常见的是，每个人在控制其他模型拥有的财产的过程中都可以保持同步:
Trivially, the spinner and slider can control each other. More commonly, each can stay synchronized in the course of controlling a property held by another model:
model.xProperty().bindBidirectional(slider.valueProperty());
model.xProperty().bindBidirectional(spinner.getValueFactory().valueProperty());
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);
}
}
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