java JavaFX | CheckMenuItem 带示例

JavaFX | CheckMenuItem 带示例

原文:https://www . geeksforgeeks . org/JavaFX-checkmenuitem-with-examples/

CheckMenuItem 是 JavaFX 库的一部分。CheckMenuItem 可以添加到菜单中，它有两种状态:选中和未选中。用户可以在这两种状态之间切换菜单。CheckMenuItem 继承自 MenuItem 类。

类的构造函数有:

CheckMenuItem(String t) :用指定的文本创建一个 CheckMenuItem
CheckMenuItem(字符串 t，节点 g) :用指定的文本和图形创建一个 CheckMenuItem

常用方法:

方法	说明
isSelected()	返回 menuitem 是否被选中
所选属性（）	表示此 CheckMenuItem 的当前状态
设置选定(布尔 v)	设置选定属性的值

下面的程序说明了 JavaFX 的 CheckMenuItem 类:

Java program to create a menu bar and add a menu to it and also add checkmenuitems to menu: This program creates a menubar indicated by the name menu_bar. A menu will be created by name menu and 3 checkmenuitems menuitem1, menuitem2, menuitem3 will be added to the menu and the menu will be added to the menubar menu_bar. The menubar will be created inside a scene, which in turn will be hosted inside a stage. The function setTitle() is used to provide title to the stage. Then a VBox is created, on which addChildren() method is called to attach the menubar inside the scene. Finally, the show() method is called to display the final results.

```java // Java program to create a menu bar and add // menu to it and also add checkmenuitems to menu import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.layout.; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.control.; import javafx.stage.Stage; import javafx.scene.control.Alert.AlertType; import java.time.LocalDate; public class checkmenuitems_0 extends Application {

// launch the application     public void start(Stage stage)     {         // set title for the stage         stage.setTitle("creating check menu items");

// create a menu         Menu menu = new Menu("Menu");

// create menuitems         CheckMenuItem menuitem1 = new CheckMenuItem("menu item 1");         CheckMenuItem menuitem2 = new CheckMenuItem("menu item 2");         CheckMenuItem menuitem3 = new CheckMenuItem("menu item 3");

// add menu items to menu         menu.getItems().add(menuitem1);         menu.getItems().add(menuitem2);         menu.getItems().add(menuitem3);

// create a menubar         MenuBar menu_bar = new MenuBar();

// add menu to menubar         menu_bar.getMenus().add(menu);

// create a VBox         VBox vbox = new VBox(menu_bar);

// create a scene         Scene scene = new Scene(vbox, 500, 300);

// set the scene         stage.setScene(scene);

stage.show();     }

public static void main(String args[])     {         // launch the application         launch(args);     } } ```

输出:
Java program to create a menu bar and add menu to it and also add checkmenuitems to menu and also add an event handler to handle the events: This program creates a menubar indicated by the name menu_bar. A menu will be created by name menu and 3 checkmenuitems menuitem1, menuitem2, menuitem3 will be added to the menu and the menu will be added to the menubar menu_bar. The menubar will be created inside a scene, which in turn will be hosted inside a stage. The function setTitle() is used to provide title to the stage. Then a VBox is created, on which addChildren() method is called to attach the menubar inside the scene. Finally, the show() method is called to display the final results. A label will also be created that will show which checkmenuitem is selected. An action event will be created to process the action when the check menu item is clicked by the user.

```java // Java program to create a menu bar and add // menu to it and also add checkmenuitems to menu // and also add event handler to handle the events import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.layout.; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.control.; import javafx.stage.Stage; import javafx.scene.control.Alert.AlertType; import java.time.LocalDate; public class checkmenuitems_2 extends Application {

// launch the application     public void start(Stage stage)     {         // set title for the stage         stage.setTitle("creating check menu items");

// create a menu         Menu menu = new Menu("Menu");

// create menuitems         CheckMenuItem menuitem1 = new CheckMenuItem("menu item 1");         CheckMenuItem menuitem2 = new CheckMenuItem("menu item 2");         CheckMenuItem menuitem3 = new CheckMenuItem("menu item 3");

// add menu items to menu         menu.getItems().add(menuitem1);         menu.getItems().add(menuitem2);         menu.getItems().add(menuitem3);

// label to display events         Label description = new Label("\t\t\t\t"                                       + "no menu item selected");

// create events for menu items         // action event         EventHandler event = new EventHandler() {             public void handle(ActionEvent e)             {                 if (((CheckMenuItem)e.getSource()).isSelected())                     description.setText                      ("\t\t\t\t" + ((CheckMenuItem)e.getSource())                        .getText() + " selected");                 else                     description.setText                      ("\t\t\t\t" + ((CheckMenuItem)e.getSource())                        .getText() + " deselected");             }         };

// add event         menuitem1.setOnAction(event);         menuitem2.setOnAction(event);         menuitem3.setOnAction(event);

// create a menubar         MenuBar menu_bar = new MenuBar();

// add menu to menubar         menu_bar.getMenus().add(menu);

// create a VBox         VBox vbox = new VBox(menu_bar, description);

// create a scene         Scene scene = new Scene(vbox, 500, 300);

// set the scene         stage.setScene(scene);

stage.show();     }

public static void main(String args[])     {         // launch the application         launch(args);     } } ```

输出:

注意:上述程序可能无法在联机 IDE 中运行，请使用脱机编译器。

参考:https://docs . Oracle . com/JavaFX/2/API/JavaFX/scene/control/checkmenuitem . html