重新填充 TreeTableView 后单击 TreeTableCell 时出现 Javafx 异常

Javafx exception when clicking TreeTableCell after repopulating TreeTableView

我目前收到一个我不明白的错误。抛出的异常在我的代码中没有指向任何内容,但它仅在我通过清除根项的子项并向其添加新的 set och 子项来重新填充 TreeTableView 后抛出。

这是个例外:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at javafx.scene.control.TreeTableView$TreeTableViewArrayListSelectionModel.handleSelectedCellsListChangeEvent(TreeTableView.java:3056)
at javafx.scene.control.TreeTableView$TreeTableViewArrayListSelectionModel.clearAndSelect(TreeTableView.java:2527)
at com.sun.javafx.scene.control.behavior.TableCellBehaviorBase.simpleSelect(TableCellBehaviorBase.java:209)
at com.sun.javafx.scene.control.behavior.TableCellBehaviorBase.doSelect(TableCellBehaviorBase.java:148)
at com.sun.javafx.scene.control.behavior.CellBehaviorBase.mousePressed(CellBehaviorBase.java:132)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:95)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3724)
at javafx.scene.Scene$MouseHandler.access00(Scene.java:3452)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
at com.sun.glass.ui.View.notifyMouse(View.java:925)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null1(WinApplication.java:102)
at com.sun.glass.ui.win.WinApplication$$Lambda/1798286609.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)

一个小型 MCVE(按“-”以重新填充 TreeTableView,然后编辑一个单元格以获取异常):

package test;

import javafx.application.Application;
import javafx.beans.value.ObservableValue;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.TitledPane;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeTableColumn;
import javafx.scene.control.TreeTableColumn.CellDataFeatures;
import javafx.scene.control.TreeTableColumn.CellEditEvent;
import javafx.scene.control.TreeTableView;
import javafx.scene.control.cell.TextFieldTreeTableCell;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.stage.Stage;
import javafx.util.Callback;

public class BillingTableTest extends Application {

    private Stage stage;
    private Scene scene;
    private TitledPane pane;

    private TreeTableView<String> table;
    private TreeItem<String> root;

    /**
     * Start the program from scratch.
     * 
     * @param args
     *            Input arguments. Leave empty.
     */
    public static void main(String[] args) {
        launch(args);
    }

    /**
     * Start the program. Not usually called by the user, but by JavaFX. Nothing
     * fancy here, but setting up a basic TreeTableView with one column.
     */
    public void start(Stage stage) {
        this.stage = stage;
        pane = new TitledPane();
        scene = new Scene(pane);

        pane.setOnKeyReleased(new EventHandler<KeyEvent>() {

            @Override
            public void handle(KeyEvent event) {
                // TODO Auto-generated method stub
                if (event.getCode() == KeyCode.SUBTRACT) {
                    repopulate();
                }
            }
        });

        table = new TreeTableView<>();

        root = new TreeItem<>("Root");
        root.setExpanded(true);

        table.setRoot(root);
        table.setShowRoot(false);
        table.setEditable(true);

        TreeTableColumn<String, String> column = new TreeTableColumn<String, String>("String");

        column.setCellValueFactory(new Callback<TreeTableColumn.CellDataFeatures<String, String>, ObservableValue<String>>() {
            @Override
            public ObservableValue<String> call(CellDataFeatures<String, String> param) {
                // TODO Auto-generated method stub
                return param.getValue().valueProperty();
            }
        });
        column.setCellFactory(TextFieldTreeTableCell.forTreeTableColumn());
        column.setOnEditCommit(new EventHandler<TreeTableColumn.CellEditEvent<String, String>>() {
            @Override
            public void handle(CellEditEvent<String, String> t) {
                t.getTreeTablePosition().getTreeItem().setValue(t.getNewValue());
            }
        });

        table.getColumns().add(column);

        populate();

        pane.setContent(table);

        stage.setScene(scene);
        stage.show();

        System.out.println("TreeTableView has not been repopulated. Editing will not throw an exception.");
        System.out.println("Press - to repopulate it and break it.");
    }

    /**
     * Populate the TreeTableView with some dummy data.
     */
    private void populate() {
        for (int i = 1; i <= 10; i++) {
            String string = "String " + i;
            TreeItem<String> treeItem = new TreeItem<String>(string);
            root.getChildren().add(treeItem);
        }
    }

    /**
     * Clear root children (clears the TreeTableView). Cell editing is most
     * likely broken by this.
     */
    private void clear() {
        root.getChildren().clear(); // <- Most likely the problem.
    }

    /**
     * Repopulate the root node (repopulate the TreeTableView). After this
     * method is called, cell editing will throw an excetion.
     */
    private void repopulate() {
        clear(); // <- Most likely the problem.
        populate();
        System.out.println("TreeTableView has been repopulated. Editing will now throw an exception");
    }

}

我知道该错误与选择 TreeTableCells 有关,并且在第一次重新填充 table 之后选择一个时会发生此错误。否则,在重新填充之前,一切都按预期工作,并且不会抛出任何异常。

有什么问题?是否不允许清除 TreeTableRoow 中的子 ObservableList,还是应该以其他方式完成?

    private void populate() {
    root.getChildren().clear()
    for (int i = 1; i <= 10; i++) {
        String string = "String " + i;
        TreeItem<String> treeItem = new TreeItem<String>(string);
        root.getChildren().add(treeItem);

        // --------------Clear the selection -------------
        table.getSelectionModel().clearSelection();
        // -----------------------------------------------

    }
}