JavaFX - MenuButton

 正在界面上显示一个按钮，点击后弹出item，可设置快捷键，在点击后按钮上显示点击哪个item

package sample;


import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Menu;
import javafx.scene.control.MenuBar;
import javafx.scene.control.MenuButton;
import javafx.scene.control.MenuItem;
import javafx.scene.image.ImageView;
import javafx.scene.input.KeyCombination;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;


public class Main extends Application {


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

    @Override
    public void start(Stage primaryStage) throws Exception {
        AnchorPane ap = new AnchorPane();
        // menubar，
        MenuBar menuBar = new MenuBar();
        // menu，
        Menu menu1 = new Menu("MENU1");
        Menu menu2 = new Menu("MENU2");
        Menu menu3 = new Menu("MENU3");
        MenuItem item1 = new MenuItem("item1");

        MenuItem item2 = new MenuItem("item2");
        MenuItem item3 = new MenuItem("小火车", 
        MenuItem item4 = new MenuItem("item4");
        MenuItem item5 = new MenuItem("item5");
        item5.setAccelerator(KeyCombination.valueOf("ctrl+k"));
        MenuItem item6 = new MenuItem("item6");
        item6.setAccelerator(KeyCombination.valueOf("ctrl+j"));

        ap.setStyle("-fx-background-color: antiquewhite");


        MenuButton mbt = new MenuButton("mbt");
        ap.setTopAnchor(mbt, 30.0);
        mbt.getItems().addAll(item5, item6);
        //i5单击事件
        item5.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                mbt.setText("点击i5");
            }
        });
        //i5的快捷键事件
        item5.setOnMenuValidation(new EventHandler<Event>() {
            @Override
            public void handle(Event event) {
                System.out.println("点击5");
            }
        });
        //i6单击事件
        item6.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                mbt.setText("点击i6");
            }
        });
        //i6快捷键事件
        item6.setOnMenuValidation(new EventHandler<Event>() {
            @Override
            public void handle(Event event) {
                System.out.println("点击6");
            }
        });
        ap.getChildren().addAll(menuBar, mbt);




        menuBar.getMenus().addAll(menu1, menu2, menu3);
        menu1.getItems().addAll(item1, item2, item3, item4);

        Scene scene = new Scene(ap);


        primaryStage.setScene(scene);
        primaryStage.setTitle("Java FX - MenuButton ");
        primaryStage.setWidth(500);
        primaryStage.setHeight(300);

        primaryStage.show();
        menuBar.setPrefWidth(primaryStage.getWidth());
        ap.widthProperty().addListener(new ChangeListener<Number>() {//menubar的长度随着框的长度改变
            @Override
            public void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue) {
                menuBar.setPrefWidth(primaryStage.getWidth());
            }
        });
    }


}