1

从http://docs.oracle.com/javafx/2/ui_controls/tree-view.htm 获取示例 13-3“实现单元工厂” 并添加行

box.addEventHandler(EventType.ROOT, new EventHandler<Event>() {
@Override
    public void handle(Event event) {
         System.out.println("event "+event);
    }
});

在 start 方法中，双击员工节点时会抛出以下异常：

java.lang.ClassCastException: javafx.scene.layout.VBox cannot be cast to javafx.scene.control.TreeView
    at javafx.scene.control.TreeView$EditEvent.getSource(TreeView.java:988)
    at javafx.scene.control.TreeView$EditEvent.getSource(TreeView.java:965)
    at com.sun.javafx.event.EventHandlerManager.fixEventSource(EventHandlerManager.java:225)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:216)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Node.fireEvent(Node.java:6863)
    at javafx.scene.control.TreeCell.startEdit(TreeCell.java:315)
    at test.TreeViewSample$TextFieldTreeCellImpl.startEdit(TreeViewSample.java:100)
    at javafx.scene.control.TreeCell.updateEditing(TreeCell.java:435)
    at javafx.scene.control.TreeCell.access$500(TreeCell.java:67)
    at javafx.scene.control.TreeCell$6.invalidated(TreeCell.java:151)
    at javafx.beans.WeakInvalidationListener.invalidated(WeakInvalidationListener.java:80)
    at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:359)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:100)
    at javafx.beans.property.ReadOnlyObjectWrapper$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyObjectWrapper.java:195)
    at javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:161)
    at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:130)
    at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:163)
    at javafx.scene.control.TreeView.setEditingItem(TreeView.java:573)
    at javafx.scene.control.TreeView.edit(TreeView.java:771)
    at com.sun.javafx.scene.control.behavior.TreeCellBehavior.simpleSelect(TreeCellBehavior.java:257)
    at com.sun.javafx.scene.control.behavior.TreeCellBehavior.doSelect(TreeCellBehavior.java:213)
    at com.sun.javafx.scene.control.behavior.TreeCellBehavior.mouseReleased(TreeCellBehavior.java:132)
    at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:336)
    at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:329)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:64)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3328)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
    at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3123)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2265)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:250)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:173)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:292)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:528)
    at com.sun.glass.ui.View.notifyMouse(View.java:922)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
    at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
    at java.lang.Thread.run(Unknown Source)

这是一个错误还是我做错了什么？

完整的示例代码（您需要在同一目录中包含文件“root.png”和“department.png”）：

package test;

import java.util.*;

import javafx.application.*;
import javafx.beans.property.*;
import javafx.event.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.image.*;
import javafx.scene.input.*;
import javafx.scene.layout.*;
import javafx.scene.paint.*;
import javafx.stage.*;
import javafx.util.*;

public class TreeViewSample extends Application {

private final Node rootIcon = 
    new ImageView(new Image(getClass().getResourceAsStream("root.png")));
private final Image depIcon = 
    new Image(getClass().getResourceAsStream("department.png"));
List<Employee> employees = Arrays.<Employee>asList(
        new Employee("Ethan Williams", "Sales Department"),
        new Employee("Emma Jones", "Sales Department"),
        new Employee("Michael Brown", "Sales Department"),
        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<String>("MyCompany Human Resources", rootIcon);

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

@Override
public void start(Stage stage) {
    rootNode.setExpanded(true);
    for (Employee employee : employees) {
        TreeItem<String> empLeaf = new TreeItem<String>(employee.getName(), new ImageView(depIcon));
        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<String>(
                employee.getDepartment(), 
                new ImageView(depIcon)
            );
            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<String> treeView = new TreeView<String>(rootNode);
    treeView.setEditable(true);
    treeView.setCellFactory(new Callback<TreeView<String>,TreeCell<String>>(){
        @Override
        public TreeCell<String> call(TreeView<String> p) {
            return new TextFieldTreeCellImpl();
        }
    });

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

    box.addEventHandler(EventType.ROOT, new EventHandler<Event>() {
        @Override
        public void handle(Event event) {
            System.out.println("event "+event);
        }
    });
}

private final class TextFieldTreeCellImpl extends TreeCell<String> {

    private TextField textField;

    public TextFieldTreeCellImpl() {
    }

    @Override
    public void startEdit() {
        super.startEdit();

        if (textField == null) {
            createTextField();
        }
        setText(null);
        setGraphic(textField);
        textField.selectAll();
    }

    @Override
    public void cancelEdit() {
        super.cancelEdit();
        setText((String) getItem());
        setGraphic(getTreeItem().getGraphic());
        System.out.println(" item canceled "+getItem());
    }

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

        if (empty) {
            setText(null);
            setGraphic(null);
        } else {
            if (isEditing()) {
                if (textField != null) {
                    textField.setText(getString());
                }
                setText(null);
                setGraphic(textField);
            } else {
                setText(getString());
                setGraphic(getTreeItem().getGraphic());
            }
        }
    }

    private void createTextField() {
        textField = new TextField(getString());
        textField.setOnKeyReleased(new EventHandler<KeyEvent>() {

            @Override
            public void handle(KeyEvent t) {
                if (t.getCode() == KeyCode.ENTER) {
                    commitEdit(textField.getText());
                } else if (t.getCode() == KeyCode.ESCAPE) {
                    cancelEdit();
                }
            }
        });
    }

    private String getString() {
        return getItem() == null ? "" : getItem().toString();
    }
}

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);
    }
}

}

4

1 回答 1

1

他们的代码确实有一点问题。您可以通过删除这些行来避免此异常：

    box.addEventHandler(EventType.ROOT, new EventHandler<Event>() {
         @Override
         public void handle(Event event) {
                System.out.println("event "+event);
         }
    });

这就是问题的根源。Vbox 捕获每个抛出的事件（因为你告诉它这样做EventType.ROOT）。而且我怀疑它会在您双击时捕获由 TreeCell 或 TreeView 引发的事件。

这样做会更好，因为它只会捕获来自用户的输入事件：

    box.addEventHandler(InputEvent.ANY , new EventHandler<InputEvent>()
于 2013-07-29T09:07:20.880 回答