單擊單元格進行編輯時，JavaFX 8 TreeView顯示不正確的字符串

Question

我正在使用來自Oracle的以下代碼：

import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Callback;

import javafx.beans.property.SimpleStringProperty;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.layout.VBox;

public class TreeViewSample extends Application {

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");

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());
        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 depNode = new TreeItem(employee.getDepartment());
            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();
}

private final class TextFieldTreeCellImpl extends TreeCell<String> {

    private TextField textField;
    private ContextMenu addMenu = new ContextMenu();

    public TextFieldTreeCellImpl() {
        MenuItem addMenuItem = new MenuItem("Add Employee");
        addMenu.getItems().add(addMenuItem);
        addMenuItem.setOnAction(new EventHandler() {
            public void handle(Event t) {
                TreeItem newEmployee = 
                    new TreeItem<String>("New Employee");
                        getTreeItem().getChildren().add(newEmployee);
            }
        });
    }

    @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());
    }

    @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());
                if (
                    !getTreeItem().isLeaf()&&getTreeItem().getParent()!= null
                ){
                    setContextMenu(addMenu);
                }
            }
        }
    }

    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);
    }
}
}

這段代碼生成的GUI具有非常基本的可編輯TreeView。 但是，當在填充樹的單元格周圍單擊時，最終，用於編輯的文本字段將開始顯示不正確的信息（該信息包含在樹中，但未被正在編輯的單元格表示）。 我不明白為什么會這樣，而且我在Google的任何地方或StackOverflow的其他地方都找不到這種情況的參考。 如果有人可以幫助我了解為什么會這樣，我將非常高興。

謝謝！

Answer 1

我檢查了您的申請，發現只有一件奇怪的事情。 一次創建編輯文本字段時，未保存的信息稍后將在該文本字段中顯示。

此修改將解決該問題：

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

    this.setText(this.getItem());
    this.textField.setText(this.getItem());
    this.setGraphic(this.getTreeItem().getGraphic());
}