Question

想象一下定义鼠标模式的枚举：

public enum MouseMode {
SELECTION,
EDITING,
DELETING }

假设有一个由3个按钮组成的切换组：

    ToggleButton selection = new ToggleButton("Select");
    ToggleButton editing = new ToggleButton("Edit");
    ToggleButton deleting = new ToggleButton("Delete");
    ToggleGroup mouseSelection = new ToggleGroup();

我希望字段MouseMode currentMode与切换组双向链接。无论何时设置切换，currentMode都会相应切换，但如果某个外部进程更改了currentMode（可能是按键），则切换组会相应地进行调整。

我可以用2个听众做到这一点，但我想知道是否有办法创建自定义双向地图。

Answer 1

我认为没有办法直接这样做。虽然是通用的

Bindings.bindBidirectional(Property<S> property1, Property<T> property2, Function<S,T> mapping, Function<T,S> inverseMapping)

可能是API的一个很好的补充，即使在这种情况下也没有用，因为ToggleGroup的{{1}}是只读的（因为选择需要在每个{{1调用了selectedProperty方法，以及Toggle的{{1}}）。

在这种情况下，使用几个听众就可以了。

与“自定义双向地图”最接近的是

setSelected(...)

方法。如果您有（可写）ToggleGroup和（可写）selectedProperty，理论上您可以使用两个双向绑定和一个中间Bindings.bindBiDirectional(StringProperty stringProperty, ObjectProperty<T> otherProperty, StringConverter<T> converter)将它们绑定在一起。在实践中，这几乎总是比使用两个监听器更多的代码，而且效率也较低。

Answer 2

我已成功使用JFXtras项目中的ToggleGroupValue类。它只在2.2代码库中，而不是8.0，但它很容易复制到您自己的代码库。 https://github.com/JFXtras/jfxtras-labs/blob/2.2/src/main/java/jfxtras/labs/scene/control/ToggleGroupValue.java

以下是一个例子：

import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.RadioButton;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class Main extends Application {
    Child myChild = new Child();
    @Override
    public void start( Stage stage ) throws Exception {
        stage.setTitle( "ToggleGroupValue Example" );
        GridPane gridPane = new GridPane();
        int rowIndex = 0;
        gridPane.add( new Label("Nickname: "), 0, rowIndex );

        ToggleGroupValue toggleGroupValue = new ToggleGroupValue();
        rowIndex = createAddRadioButtons( gridPane, rowIndex, toggleGroupValue );

        gridPane.add( new Label("Selected Nickname: "), 0, rowIndex );
        Label selectedNickNameValueLabel = new Label();
        gridPane.add( selectedNickNameValueLabel, 1, rowIndex );

        myChild.nicknameProperty().bindBidirectional( toggleGroupValue.valueProperty() );
        selectedNickNameValueLabel.textProperty().bind( toggleGroupValue.valueProperty() );

        stage.setScene( new Scene( gridPane, 300, 100 ) );
        stage.show();
    }

    private int createAddRadioButtons( GridPane gridPane, int rowIndex, ToggleGroupValue toggleGroupValue ) {
        RadioButton radioButtonPunkin = new RadioButton();
        radioButtonPunkin.setUserData( "Punkin" );
        RadioButton radioButtonLittleBoy = new RadioButton();
        radioButtonLittleBoy.setUserData( "Little Boy" );
        RadioButton radioButtonBuddy = new RadioButton();
        radioButtonBuddy.setUserData( "Buddy" );
        List<RadioButton> radioButtons = Arrays.asList( radioButtonPunkin, radioButtonLittleBoy, radioButtonBuddy );
        for ( RadioButton radioButton : radioButtons ) {
            toggleGroupValue.add( radioButton, radioButton.getUserData() );
            radioButton.setText( radioButton.getUserData().toString() );
            gridPane.add( radioButton, 1, rowIndex++ );
        }
        return rowIndex;
    }

    private static class Child {
        private StringProperty nickname = new SimpleStringProperty();
        public StringProperty nicknameProperty() {
            return nickname;
        }
        public String getNickname() {
            return nickname.get();
        }
        public void setNickname( String notesProperty ) {
            this.nickname.set( notesProperty );
        }
    }

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

screenshot of javafx example application

Answer 3

我使用的是Java bean属性适配器，但您可以使用此代码的最后一行并绑定它。

JavaBeanObjectProperty<fooEnum> property = null;
    try {
        property = new JavaBeanObjectPropertyBuilder<fooEnum>().bean(fooBean).name(fooField).build();
    } catch (NoSuchMethodException e1) {
        e1.printStackTrace();
    }
    property.addListener((obs, oldValue, newValue) -> {
        System.out.println("Property value changed from " + oldValue + " to " + newValue);
    });
BindingUtils.bindToggleGroupToProperty(fooToggleGroup, property);

你需要为ToggleGroup设置一个小的BindingUtils类。

public final class BindingUtils {

private BindingUtils() {
}

public static <T> void bindToggleGroupToProperty(final ToggleGroup toggleGroup, final ObjectProperty<T> property) {
    // Check all toggles for required user data
    toggleGroup.getToggles().forEach(toggle -> {
        if (toggle.getUserData() == null) {
            throw new IllegalArgumentException("The ToggleGroup contains at least one Toggle without user data!");
        }
    });
    // Select initial toggle for current property state
    for (Toggle toggle : toggleGroup.getToggles()) {
        if (property.getValue() != null && property.getValue().equals(toggle.getUserData())) {
            toggleGroup.selectToggle(toggle);
            break;
        }
    }
    // Update property value on toggle selection changes
    toggleGroup.selectedToggleProperty().addListener((observable, oldValue, newValue) -> {
        property.setValue((T) newValue.getUserData());
    });
}

Answer 4

这个答案的灵感来自tunabot。这个答案将使用 RadioButton 而不是使用 ToogleButton，为了使它看起来更漂亮，我们将使用 ControlsFX 中的 SegmentedButton。我们可以使用 valueProperty 中的 ToggleGroupValue 绑定双向选中的切换按钮。

有一个调试按钮，当我们点击这个按钮时，选中的按钮会变成 DELETING 按钮。

import javafx.application.Application;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ToggleButton;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import jfxtras.scene.control.ToggleGroupValue;
import org.controlsfx.control.SegmentedButton;

public class ToggleBindingDemo extends Application{
    public static void main(String[] args){
        launch(args);
    }

    private final ObjectProperty<MouseMode> mouseModeObjectProperty = new SimpleObjectProperty<>(MouseMode.SELECTION);;

    @Override
    public void start(Stage stage){
        ToggleGroupValue<MouseMode> toggleGroupValue = new ToggleGroupValue<>();

        ToggleButton selection = new ToggleButton("Selection");
        selection.setUserData(MouseMode.SELECTION);
        selection.setToggleGroup(toggleGroupValue);

        ToggleButton editing = new ToggleButton("Editing");
        editing.setUserData(MouseMode.EDITING);
        editing.setToggleGroup(toggleGroupValue);

        ToggleButton deleting = new ToggleButton("Deleting");
        deleting.setUserData(MouseMode.DELETING);
        deleting.setToggleGroup(toggleGroupValue);

        toggleGroupValue.valueProperty().bindBidirectional(mouseModeObjectProperty);
        mouseModeObjectProperty.addListener(new ChangeListener<MouseMode>(){
            @Override
            public void changed(ObservableValue<? extends MouseMode> observable, MouseMode oldValue, MouseMode newValue){
                System.out.println("MouseMode: " + newValue);
            }
        });

        SegmentedButton segmentedButton = new SegmentedButton(selection, editing, deleting);
        segmentedButton.setToggleGroup(toggleGroupValue);
        Button debugButton = new Button("Debug");
        debugButton.setOnMouseClicked(event -> handleDebugClick());

        VBox vBox = new VBox(segmentedButton, debugButton);
        vBox.setSpacing(10);
        StackPane root = new StackPane(vBox);

        Scene scene = new Scene(root, 400, 400);
        stage.setScene(scene);
        stage.show();
    }

    void handleDebugClick(){
        mouseModeObjectProperty.set(MouseMode.DELETING);
    }

    public enum MouseMode{
        SELECTION,
        EDITING,
        DELETING
    }
}

在javafx中双向绑定ToggleGroup

4 个答案: