Die Anleitung zu JavaFX ContextMenu

1- JavaFX ContextMenu

Wenn Sie kein Raum der Benutzer - Schnittstelle für eine notwendige Funktion geben, können Sie ein ContextMenu. Ein ContextMenu : ein Pop-up Fenster erscheint bei einer Mausklick. Ein ContextMenu besteht aus ein oder viele Menu
Beachten Sie: ContextMenu ist ziemlich gleich mit ein Menu, Sie können die Item wie  MenuItem, CheckMenuItem, RadioMenuItem und  SeparatorMenuItem addieren.

2- Zum Beispiel ContextMenu

Das folgend einfach Beispiel: Wenn der Benutzer ein Runde klickt, erscheint ein ContextMenu
 
ContextMenuDemo.java
package org.o7planning.javafx.contextmenu;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.Label;
import javafx.scene.control.MenuItem;
import javafx.scene.input.ContextMenuEvent;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class ContextMenuDemo extends Application {

    @Override
    public void start(Stage stage) {

        Label label = new Label();

        Circle circle = new Circle();
        circle.setRadius(80);
        circle.setFill(Color.AQUA);

        VBox root = new VBox();
        root.setPadding(new Insets(5));
        root.setSpacing(5);

        root.getChildren().addAll(label, circle);

        // Create ContextMenu
        ContextMenu contextMenu = new ContextMenu();

        MenuItem item1 = new MenuItem("Menu Item 1");
        item1.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                label.setText("Select Menu Item 1");
            }
        });
        MenuItem item2 = new MenuItem("Menu Item 2");
        item2.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                label.setText("Select Menu Item 2");
            }
        });

        // Add MenuItem to ContextMenu
        contextMenu.getItems().addAll(item1, item2);

        // When user right-click on Circle
        circle.setOnContextMenuRequested(new EventHandler<ContextMenuEvent>() {

            @Override
            public void handle(ContextMenuEvent event) {

                contextMenu.show(circle, event.getScreenX(), event.getScreenY());
            }
        });

        Scene scene = new Scene(root, 400, 200);

        stage.setTitle("JavaFX ContextMenu (o7planning.org)");
        stage.setScene(scene);
        stage.show();
    }

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

}

3- Der Akzelerator(Accelerator) und die  MenuItem

Wie Menu können Sie die Item wie   MenuItem, CheckMenuItem, RadioMenuItem, SeparatorMenuItem in   ContextMenu addieren. Sie können die Accelerator für Item anwenden. und der Benutzer können die Accelerator benutzen statt dem Klicken von Item
ContextMenuDemo2.java
package org.o7planning.javafx.contextmenu;

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.CheckMenuItem;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.Menu;
import javafx.scene.control.MenuItem;
import javafx.scene.control.RadioMenuItem;
import javafx.scene.control.SeparatorMenuItem;
import javafx.scene.control.ToggleGroup;
import javafx.scene.input.ContextMenuEvent;
import javafx.scene.input.KeyCombination;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class ContextMenuDemo2 extends Application {

    @Override
    public void start(Stage stage) {

        Circle circle = new Circle();
        circle.setRadius(80);
        circle.setFill(Color.AQUA);

        VBox root = new VBox();
        root.setPadding(new Insets(5));
        root.setSpacing(5);

        root.getChildren().addAll(circle);

        // Create ContextMenu
        ContextMenu contextMenu = new ContextMenu();

        MenuItem menuItem = new MenuItem("Menu Item");

        // Set accelerator to menuItem.
        menuItem.setAccelerator(KeyCombination.keyCombination("Ctrl+O"));

        Menu parentMenu = new Menu("Parent");
        MenuItem childMenuItem1 = new MenuItem("Child 1");
        MenuItem childMenuItem2 = new MenuItem("Child 2");
        parentMenu.getItems().addAll(childMenuItem1, childMenuItem2);

        CheckMenuItem checkMenuItem = new CheckMenuItem("Check Menu Item");
        checkMenuItem.setSelected(true);

        SeparatorMenuItem separatorMenuItem = new SeparatorMenuItem();

        RadioMenuItem radioMenuItem1 = new RadioMenuItem("Radio - Option 1");
        RadioMenuItem radioMenuItem2 = new RadioMenuItem("Radio - Option 2");
        ToggleGroup group = new ToggleGroup();

        radioMenuItem1.setToggleGroup(group);
        radioMenuItem2.setToggleGroup(group);

        // Add MenuItem to ContextMenu
        contextMenu.getItems().addAll(menuItem, parentMenu, checkMenuItem, //
                separatorMenuItem, radioMenuItem1, radioMenuItem2);

        // When user right-click on Circle
        circle.setOnContextMenuRequested(new EventHandler<ContextMenuEvent>() {

            @Override
            public void handle(ContextMenuEvent event) {

                contextMenu.show(circle, event.getScreenX(), event.getScreenY());
            }
        });

        Scene scene = new Scene(root, 400, 200);

        stage.setTitle("JavaFX ContextMenu (o7planning.org)");
        stage.setScene(scene);
        stage.show();
    }

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

}

4- ContextMenu und das Event

Es gibt einige Ereignis von ContextMenu, die Ihnen nützlich sein wie onShowing ist ein Ereignis, die stattfindet bevor ein ContextMenu erscheint. Sie können die Ereignis für etwas benutzen wie MenuItem in ContextMenu hinzufügen
// Called just prior to the ContextMenu being shown.
public final void setOnShowing(EventHandler<WindowEvent> value)

// Called just after the ContextMenu is shown.
public final void setOnShown(EventHandler<WindowEvent> value)

// Called just prior to the ContextMenu being hidden.
public final void setOnHiding(EventHandler<WindowEvent> value)

// Called just after the ContextMenu has been hidden.
public final void setOnHidden(EventHandler<WindowEvent> value)

// Called when there is an external request to close this
public final void setOnCloseRequest(EventHandler<WindowEvent> value)
ContextMenuEventDemo.java
package org.o7planning.javafx.contextmenu;

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.control.TextArea;
import javafx.scene.input.ContextMenuEvent;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
import javafx.stage.WindowEvent;

public class ContextMenuEventDemo extends Application {

  private int index = 1;

  @Override
  public void start(Stage stage) {

      TextArea textArea = new TextArea();
      textArea.setMinHeight(100);

      Circle circle = new Circle();
      circle.setRadius(80);
      circle.setFill(Color.GRAY);

      VBox root = new VBox();
      root.setPadding(new Insets(5));
      root.setSpacing(5);

      root.getChildren().addAll(textArea, circle);

      // Create ContextMenu
      ContextMenu contextMenu = new ContextMenu();
      MenuItem menuItem = new MenuItem("Menu Item");
      contextMenu.getItems().add(menuItem);

      // When user right-click on Circle
      circle.setOnContextMenuRequested(new EventHandler<ContextMenuEvent>() {

          @Override
          public void handle(ContextMenuEvent event) {

              contextMenu.show(circle, event.getScreenX(), event.getScreenY());
          }
      });
      // Called just prior to the ContextMenu being shown.
      // Add new MenuItem to ContextMenu.
      contextMenu.setOnShowing(new EventHandler<WindowEvent>() {

          @Override
          public void handle(WindowEvent event) {
              textArea.appendText("On Showing..\n");

              MenuItem menuItem = new MenuItem("New Menu Item " + index++);
              contextMenu.getItems().add(menuItem);
          }
      });

      // Called just after the ContextMenu is shown.
      contextMenu.setOnShown(new EventHandler<WindowEvent>() {

          @Override
          public void handle(WindowEvent event) {
              textArea.appendText("On Show..\n");
          }
      });
   
      // Called just prior to the ContextMenu being hidden.
      contextMenu.setOnHiding(new EventHandler<WindowEvent>() {

          @Override
          public void handle(WindowEvent event) {
              textArea.appendText("On Hiding..\n");
          }
      });
   
      // Called just after the ContextMenu has been hidden.
      contextMenu.setOnHidden(new EventHandler<WindowEvent>() {

          @Override
          public void handle(WindowEvent event) {
              textArea.appendText("On Hidden..\n");
          }
      });

      Scene scene = new Scene(root, 400, 250);

      stage.setTitle("JavaFX ContextMenu (o7planning.org)");
      stage.setScene(scene);
      stage.show();
  }

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

}