Question

我有一个我无法解决的问题。我想将进度条实现到组合框中：

public class JavaFXApplication4 extends Application
{

    @Override
    public void start(Stage primaryStage)
    {

        double y1 = 15;
        ProgressBar p1 = new ProgressBar();
        p1.setLayoutY(y1);
        HBox vb1 = new HBox(10);
        vb1.getChildren().addAll(new Label("Progressbar 1"), p1);

        double y2 = 15;
        ProgressBar p2 = new ProgressBar();
        p2.setLayoutY(y2);
        HBox vb2 = new HBox(10);
        vb2.getChildren().addAll(new Label("Progressbar 2"), p2);

        double y3 = 15;
        ProgressBar p3 = new ProgressBar();
        p3.setLayoutY(y3);
        HBox vb3 = new HBox(10);
        vb3.getChildren().addAll(new Label("Progressbar 3"), p3);

        TextChooser textChooser = new TextChooser(
            vb1, vb2, vb3
        );

        textChooser.setStyle("-fx-font: 10px \"Verdana\";");

        StackPane root = new StackPane();
        root.getChildren().add(textChooser);

        Scene scene = new Scene(root, 300, 250);

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static class TextChooser extends StackPane
    {
        private Label label = new Label();

        private ComboBox<HBox> combo = new ComboBox<>();

        public TextChooser(HBox... options)
        {
            StackPane.setAlignment(label, Pos.CENTER_LEFT);
            StackPane.setAlignment(combo, Pos.CENTER_LEFT);

            label.graphicProperty().bind(
                //combo.getSelectionModel().selectedItemProperty()
                combo.getSelectionModel().selectedItemProperty()
            );
            label.visibleProperty().bind(
                combo.visibleProperty().not()
            );
            //label.setPadding(new Insets(0, 0, 0, 10));

            combo.getItems().setAll(options);

            combo.setCellFactory(new Callback<ListView<HBox>, ListCell<HBox>>()
            {
                @Override
                public ListCell<HBox> call(ListView<HBox> p)
                {
                    return new ListCell<HBox>()
                    {
                        @Override
                        protected void updateItem(HBox item, boolean empty)
                        {
                            super.updateItem(item, empty);

                            if (item == null || empty)
                            {
                                setGraphic(null);
                            }
                            else
                            {
                                setGraphic(item);
                            }
                        }
                    };
                }
            });

            combo.getSelectionModel().select(0);
            combo.setVisible(true);

            label.setOnMouseEntered(event -> combo.setVisible(true));
            combo.showingProperty().addListener(observable ->
            {
                if (!combo.isShowing())
                {
                    combo.setVisible(false);
                }
            });
            combo.setOnMouseExited(event ->
            {
                if (!combo.isShowing())
                {
                    combo.setVisible(false);
                }
            });

            getChildren().setAll(label, combo);
        }

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

您能否告诉我如何使用setButtonCell将Progressbar显示在组合框中？

Answer 1

您不应该将节点放入项目列表中 - 而应将数据存储在那里，然后使用您的单元工厂进行渲染。

例如：

public class JavaFXApplication5 extends Application
{
    public static void main( String[] args )
    {
        launch( args );
    }


    public class ProgressData
    {
        private final DoubleProperty  progressProp = new SimpleDoubleProperty();
        private final StringProperty  progressName = new SimpleStringProperty();

        public ProgressData( String name, double progress )
        {
            progressProp.set( progress );
            progressName.set( name );
        }

        public DoubleProperty progressProperty()
        {
            return  progressProp;
        }

        public StringProperty nameProperty()
        {
            return  progressName;
        }

        @Override
        //  Lazy hack for the combo button.
        public String toString()
        {
            return progressName.get();
        }
    }


    @Override
    public void start( Stage primaryStage )
    {
        ProgressData vb1 = new ProgressData( "Progressbar 1", -1 );
        ProgressData vb2 = new ProgressData( "Progressbar 2", 0.2 );
        ProgressData vb3 = new ProgressData( "Progressbar 3", 0.3 );

        TextChooser textChooser = new TextChooser( vb1, vb2, vb3 );

        textChooser.setStyle( "-fx-font: 10px \"Verdana\";" );

        StackPane root = new StackPane();
        root.getChildren().add( textChooser );

        Scene scene = new Scene( root, 300, 250 );

        primaryStage.setTitle( "Hello World!" );
        primaryStage.setScene( scene );
        primaryStage.show();
    }

    public static class TextChooser extends StackPane
    {
        private final Label label = new Label();

        private final ComboBox<ProgressData> combo = new ComboBox<>();

        public TextChooser(ProgressData... options)
        {
            StackPane.setAlignment( label, Pos.CENTER_LEFT );
            StackPane.setAlignment( combo, Pos.CENTER_LEFT );


            final ProgressBar  labelBar = new ProgressBar();
            label.visibleProperty().bind( combo.visibleProperty().not() );
            label.setContentDisplay( ContentDisplay.RIGHT );
            label.setGraphic( labelBar );


            combo.getItems().setAll( options );

            //  This will change the label's text and the progress bar value.
            combo.getSelectionModel().selectedItemProperty().addListener( new ChangeListener<ProgressData>()
            {
                @Override
                public void changed( ObservableValue<? extends ProgressData> observable, ProgressData oldValue, ProgressData newValue )
                {
                    if ( labelBar.progressProperty().isBound() )
                    {
                        labelBar.progressProperty().unbind();
                    }

                    labelBar.progressProperty().bind( newValue.progressProperty() );
                    label.setText( newValue.nameProperty().get() );
                }
            } );

            combo.setCellFactory( new Callback<ListView<ProgressData>, ListCell<ProgressData>>()
            {
                @Override
                public ListCell<ProgressData> call( ListView<ProgressData> p )
                {
                    return new ListCell<ProgressData>()
                    {
                        private final ProgressBar  cellBar = new ProgressBar();
                        {
                            cellBar.setMouseTransparent( true );
                            setContentDisplay( ContentDisplay.RIGHT );
                            setGraphic( cellBar );
                        }

                        @Override
                        protected void updateItem( ProgressData item, boolean empty )
                        {
                            super.updateItem( item, empty );

                            if ( item != null && ! empty )
                            {
                                if ( cellBar.progressProperty().isBound() )
                                {
                                    cellBar.progressProperty().unbind();
                                }
                                cellBar.progressProperty().bind( item.progressProperty() );
                                setText( item.nameProperty().get() );
                            }
                        }
                    };
                }
            } );

            combo.getSelectionModel().select( 0 );
            combo.setVisible( true );

            label.setOnMouseEntered( new EventHandler<MouseEvent>()
            {
                @Override
                public void handle( MouseEvent event )
                {
                    combo.setVisible( true );
                }
            } );

            combo.showingProperty().addListener( new InvalidationListener()
            {
                @Override
                public void invalidated( Observable observable )
                {
                    if ( !combo.isShowing() )
                    {
                        combo.setVisible( false );
                    }
                }
            } );

            combo.setOnMouseExited( new EventHandler<MouseEvent>()
            {
                @Override
                public void handle( MouseEvent event )
                {
                    if ( !combo.isShowing() )
                    {
                        combo.setVisible( false );
                    }
                }
            } );

            getChildren().setAll( label, combo );
        }

    }

}

Answer 2

我稍微改变了一下代码，因为我没有Java 8环境，它工作正常： Screenshot

代码：

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.scene.control.ProgressBar;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Callback;

public class JavaFXApplication4 extends Application
{

@Override
public void start(Stage primaryStage)
{
    double y1 = 15;
    ProgressBar p1 = new ProgressBar();
    p1.setLayoutY(y1);
    HBox vb1 = new HBox(10);
    vb1.getChildren().addAll(new Label("Progressbar 1"), p1);

    double y2 = 15;
    ProgressBar p2 = new ProgressBar();
    p2.setLayoutY(y2);
    HBox vb2 = new HBox(10);
    vb2.getChildren().addAll(new Label("Progressbar 2"), p2);

    double y3 = 15;
    ProgressBar p3 = new ProgressBar();
    p3.setLayoutY(y3);
    HBox vb3 = new HBox(10);
    vb3.getChildren().addAll(new Label("Progressbar 3"), p3);

    TextChooser textChooser = new TextChooser(
        vb1, vb2, vb3
    );

    textChooser.setStyle("-fx-font: 10px \"Verdana\";");

    StackPane root = new StackPane();
    root.getChildren().add(textChooser);

    Scene scene = new Scene(root, 300, 250);

    primaryStage.setTitle("Hello World!");
    primaryStage.setScene(scene);
    primaryStage.show();
}

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

class TextChooser extends StackPane
{
private Label label = new Label();

private ComboBox<HBox> combo = new ComboBox<>();

public TextChooser(HBox... options)
{
    StackPane.setAlignment(label, Pos.CENTER_LEFT);
    StackPane.setAlignment(combo, Pos.CENTER_LEFT);

    label.graphicProperty().bind(
        //combo.getSelectionModel().selectedItemProperty()
        combo.getSelectionModel().selectedItemProperty()
    );
    label.visibleProperty().bind(
        combo.visibleProperty().not()
    );
    //label.setPadding(new Insets(0, 0, 0, 10));

    combo.getItems().setAll(options);

    combo.setCellFactory(new Callback<ListView<HBox>, ListCell<HBox>>()
    {
        @Override
        public ListCell<HBox> call(ListView<HBox> p)
        {
            return new ListCell<HBox>()
            {
                @Override
                protected void updateItem(HBox item, boolean empty)
                {
                    super.updateItem(item, empty);

                    if (item == null || empty)
                    {
                        setGraphic(null);
                    }
                    else
                    {
                        setGraphic(item);
                    }
                }
            };
        }
    });

    combo.getSelectionModel().select(0);
    combo.setVisible(true);

    label.setOnMouseEntered(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent arg0) {
            combo.setVisible(true);

        }

    });
    combo.showingProperty().addListener(new ChangeListener<Boolean>() {

        @Override
        public void changed(ObservableValue<? extends Boolean> arg0, Boolean arg1, Boolean newVal) {
            if (!combo.isShowing())
            {
                combo.setVisible(false);
            }                   
        }
    });


    combo.setOnMouseExited(new EventHandler<MouseEvent>() 
    {
        @Override
        public void handle(MouseEvent arg0) {
             if (!combo.isShowing())
                {
                    combo.setVisible(false);
                }
        }
    });

    getChildren().setAll(label, combo);
}
}

Answer 3

好的，所以在重新编写代码的情况下，我们可以回答设置按钮单元格的问题：

private static class ButtonCell extends ListCell<ProgressData>
{
    @Override
    protected void updateItem( ProgressData item, boolean empty )
    {
        super.updateItem( item, empty );

        if ( item != null && ! empty )
        {
            setText( item.nameProperty().get() );
        }
    }
}

您在之前重新设计的代码中使用以下内容：

combo.setButtonCell( new ButtonCell() );

ComboBox的setButtonCell

3 个答案: