javafx - JavaFX 树的上下文菜单

Question

我想为 JavaFX 创建上下文菜单。这是我测试过的代码。但是由于某种原因，当我右键单击树节点时没有上下文菜单。你能帮我找出我的错误吗。

import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.ContextMenuBuilder;
import javafx.scene.control.MenuItemBuilder;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.control.cell.TextFieldTreeCell;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Callback;

public class MainApp extends Application
{
    List<Employee> employees = Arrays.<Employee>asList(
        new Employee("New Chassi", "New Datacenter"),
        new Employee("New Battery", "New Rack"),
        new Employee("New Chassi", "New Server"),
        new Employee("Anna Black", "Sales Department"),
        new Employee("Rodger York", "Sales Department"),
        new Employee("Susan Collins", "Sales Department"),
        new Employee("Mike Graham", "IT Support"),
        new Employee("Judy Mayer", "IT Support"),
        new Employee("Gregory Smith", "IT Support"),
        new Employee("Jacob Smith", "Accounts Department"),
        new Employee("Isabella Johnson", "Accounts Department"));
    TreeItem<String> rootNode = new TreeItem<>("MyCompany Human Resources");

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

    TreeView<String> treeView = new TreeView<>(rootNode);

    @Override
    public void start(Stage stage)
    {

        rootNode.setExpanded(true);
        for (Employee employee : employees)
        {
            TreeItem<String> empLeaf = new TreeItem<>(employee.getName());
            boolean found = false;
            for (TreeItem<String> depNode : rootNode.getChildren())
            {
                if (depNode.getValue().contentEquals(employee.getDepartment()))
                {
                    depNode.getChildren().add(empLeaf);
                    found = true;
                    break;
                }
            }
            if (!found)
            {
                TreeItem<String> depNode = new TreeItem<>(
                    employee.getDepartment()//,new ImageView(depIcon)   // Set picture
                );
                rootNode.getChildren().add(depNode);
                depNode.getChildren().add(empLeaf);
            }
        }

        stage.setTitle("Tree View Sample");
        VBox box = new VBox();
        final Scene scene = new Scene(box, 400, 300);
        scene.setFill(Color.LIGHTGRAY);

        treeView.setCellFactory(new Callback<TreeView<String>, TreeCell<String>>()
        {

            @Override
            public TreeCell<String> call(TreeView<String> arg0)
            {
                // custom tree cell that defines a context menu for the root tree item
                return new MyTreeCell();
            }
        });

        box.getChildren().add(treeView);
        stage.setScene(scene);
        stage.show();
    }

    public static class Employee
    {

        private final SimpleStringProperty name;
        private final SimpleStringProperty department;

        private Employee(String name, String department)
        {
            this.name = new SimpleStringProperty(name);
            this.department = new SimpleStringProperty(department);
        }

        public String getName()
        {
            return name.get();
        }

        public void setName(String fName)
        {
            name.set(fName);
        }

        public String getDepartment()
        {
            return department.get();
        }

        public void setDepartment(String fName)
        {
            department.set(fName);
        }
    }

    class MyTreeCell extends TextFieldTreeCell<String>
    {
        private ContextMenu rootContextMenu;

        public MyTreeCell()
        {
            // instantiate the root context menu
            rootContextMenu
                = ContextMenuBuilder.create()
                .items(
                    MenuItemBuilder.create()
                    .text("Menu Item")
                    .onAction(
                        new EventHandler<ActionEvent>()
                        {
                            @Override
                            public void handle(ActionEvent arg0)
                            {
                                System.out.println("Menu Item Clicked!");
                            }
                        }
                    )
                    .build()
                )
                .build();
        }

        @Override
        public void updateItem(String item, boolean empty)
        {
            super.updateItem(item, empty);

            // if the item is not empty and is a root...
            if (!empty && getTreeItem().getParent() == null)
            {
                setContextMenu(rootContextMenu);
            }
        }
    }

}

Answer 1

您应该将上下文菜单分配给 TreeView，而不是将其分配给单元工厂。这是上下文菜单工作的代码:

import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.ContextMenuBuilder;
import javafx.scene.control.MenuItemBuilder;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.control.cell.TextFieldTreeCell;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Callback;

public class Test extends Application
{
    List<Employee> employees = Arrays.<Employee>asList(
        new Employee("New Chassi", "New Datacenter"),
        new Employee("New Battery", "New Rack"),
        new Employee("New Chassi", "New Server"),
        new Employee("Anna Black", "Sales Department"),
        new Employee("Rodger York", "Sales Department"),
        new Employee("Susan Collins", "Sales Department"),
        new Employee("Mike Graham", "IT Support"),
        new Employee("Judy Mayer", "IT Support"),
        new Employee("Gregory Smith", "IT Support"),
        new Employee("Jacob Smith", "Accounts Department"),
        new Employee("Isabella Johnson", "Accounts Department"));
    TreeItem<String> rootNode = new TreeItem<>("MyCompany Human Resources");

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

    TreeView<String> treeView = new TreeView<>(rootNode);

    @Override
    public void start(Stage stage)
    {

        // instantiate the root context menu
        ContextMenu rootContextMenu
            = ContextMenuBuilder.create()
            .items(
                MenuItemBuilder.create()
                .text("Menu Item")
                .onAction(
                    new EventHandler<ActionEvent>()
                    {
                        @Override
                        public void handle(ActionEvent arg0)
                        {
                            System.out.println("Menu Item Clicked!");
                        }
                    }
                )
                .build()
            )
            .build();

        treeView.setContextMenu(rootContextMenu);

        rootNode.setExpanded(true);
        for (Employee employee : employees)
        {
            TreeItem<String> empLeaf = new TreeItem<>(employee.getName());
            boolean found = false;
            for (TreeItem<String> depNode : rootNode.getChildren())
            {
                if (depNode.getValue().contentEquals(employee.getDepartment()))
                {
                    depNode.getChildren().add(empLeaf);
                    found = true;
                    break;
                }
            }
            if (!found)
            {
                TreeItem<String> depNode = new TreeItem<>(
                    employee.getDepartment()//,new ImageView(depIcon)   // Set picture
                );
                rootNode.getChildren().add(depNode);
                depNode.getChildren().add(empLeaf);
            }
        }

        stage.setTitle("Tree View Sample");
        VBox box = new VBox();
        final Scene scene = new Scene(box, 400, 300);
        scene.setFill(Color.LIGHTGRAY);


        box.getChildren().add(treeView);
        stage.setScene(scene);
        stage.show();
    }

    public static class Employee
    {

        private final SimpleStringProperty name;
        private final SimpleStringProperty department;

        private Employee(String name, String department)
        {
            this.name = new SimpleStringProperty(name);
            this.department = new SimpleStringProperty(department);
        }

        public String getName()
        {
            return name.get();
        }

        public void setName(String fName)
        {
            name.set(fName);
        }

        public String getDepartment()
        {
            return department.get();
        }

        public void setDepartment(String fName)
        {
            department.set(fName);
        }
    }


}