javafx - 鼠标悬停时显示下拉菜单

Question

我想创建这样的下拉菜单:



我希望当我将鼠标放在文本上时可以看到我可以用来选择一个值的组合框。当我移除鼠标时，我想看到简单的标签。我怎么能做到这一点？

Answer 1

悬停:



悬停时:



单击并选择:



选择完成:

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 Hoverboard extends Application {

    public class TextChooser extends StackPane {
        private Label label = new Label();
        private ComboBox<String> combo = new ComboBox<>();

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

            label.textProperty().bind(
                combo.getSelectionModel().selectedItemProperty()
            );
            label.visibleProperty().bind(
                combo.visibleProperty().not()
            );
            label.setPadding(new Insets(0, 0, 0, 9));

            combo.getItems().setAll(options);
            combo.getSelectionModel().select(0);
            combo.setVisible(false);

            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);
        }
    }

    @Override
    public void start(Stage stage) throws Exception {
        TextChooser textChooser = new TextChooser(
            "xyzzy", "frobozz", "foobar"
        );

        VBox layout = new VBox(textChooser);
        layout.setPadding(new Insets(10));

        stage.setScene(new Scene(layout));
        stage.show();
    }

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

}