创建具有自定义可编辑单元格的JFX TableView问题

Question

我正在尝试创建一个TableView，其中包含Student对象和Classroom对象。现在，我希望有一个ChoiceBox来将Students从一个Classroom交换到另一个Classroom。

这是密码

public class ChoiceBoxCell extends TableCell<Student, Classroom> {


    ChoiceBox<Classroom> classroomChoiceBox = new ChoiceBox<>();

    public ChoiceBoxCell(ObservableList<Classroom> classroomObservableList) {
        ObservableList<Classroom> classroomObservableListList = classroomObservableList;
        classroomChoiceBox.setItems(classroomObservableListList);

        classroomChoiceBox.getSelectionModel().selectedIndexProperty().addListener((obs, oldValue, newValue) -> {
            Classroom value = classroomChoiceBox.getItems().get((int) newValue);
            classroomChoiceBox.setValue(value);
            processEdit(value);
        });
    }
    private void processEdit(Classroom value) {
        commitEdit(value);
        classroomChoiceBox.setValue(value);
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void cancelEdit() {
        super.cancelEdit();
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void commitEdit(Classroom value) {
        super.commitEdit(value);
        classroomChoiceBox.setValue(value);
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void startEdit() {
        super.startEdit();
        Classroom value = getItem();
        if (value != null) {
            classroomChoiceBox.setValue(value);
            setGraphic(classroomChoiceBox);
        }
    }

    @Override
    protected void updateItem(Classroom item, boolean empty) {
        super.updateItem(item, empty);
        if (item == null || empty) {
            classroomChoiceBox.setValue(item);
            setGraphic(classroomChoiceBox);
        } else {
            classroomChoiceBox.setValue(item);
            setGraphic(classroomChoiceBox);
        }
    }
}

在我的TableView课上

列表classroomList =新的ClassroomDao().getAllClasses()；ObservableList classroomObservableList =

classroomNameColumn.setPrefWidth(columnSize);
classroomNameColumn.setCellValueFactory(cdf -> cdf.getValue().classroomProperty());
classroomNameColumn.setCellFactory(column -> new ChoiceBoxCell(classroomObservableList));
classroomNameColumn.setEditable(true);

我得到了以下异常

Exception in thread "JavaFX Application Thread" java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.elementData(ArrayList.java:418)
at java.util.ArrayList.get(ArrayList.java:431)
at com.sun.javafx.collections.ObservableListWrapper.get(ObservableListWrapper.java:89)
at view.adminAccess.studentOverview.ChoiceBoxCell.lambda$new$0(ChoiceBoxCell.java:20)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.ReadOnlyIntegerWrapper$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyIntegerWrapper.java:176)
at javafx.beans.property.ReadOnlyIntegerWrapper.fireValueChangedEvent(ReadOnlyIntegerWrapper.java:142)
at javafx.beans.property.IntegerPropertyBase.markInvalid(IntegerPropertyBase.java:113)
at javafx.beans.property.IntegerPropertyBase.set(IntegerPropertyBase.java:147)
at javafx.scene.control.SelectionModel.setSelectedIndex(SelectionModel.java:68)
at javafx.scene.control.SingleSelectionModel.select(SingleSelectionModel.java:114)
at javafx.scene.control.ChoiceBox$4.invalidated(ChoiceBox.java:331)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
at javafx.scene.control.ChoiceBox.setValue(ChoiceBox.java:336)
at view.adminAccess.studentOverview.ChoiceBoxCell.updateItem(ChoiceBoxCell.java:58)
at view.adminAccess.studentOverview.ChoiceBoxCell.updateItem(ChoiceBoxCell.java:10)
at javafx.scene.control.TableCell.updateItem(TableCell.java:639)
at javafx.scene.control.TableCell.indexChanged(TableCell.java:468)
at javafx.scene.control.IndexedCell.updateIndex(IndexedCell.java:116)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.requestCellUpdate(TableRowSkinBase.java:659)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.lambda$init$497(TableRowSkinBase.java:159)
at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:137)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:105)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
at javafx.scene.control.Cell.setItem(Cell.java:403)
at javafx.scene.control.Cell.updateItem(Cell.java:670)
at javafx.scene.control.TableRow.updateItem(TableRow.java:268)
at javafx.scene.control.TableRow.indexChanged(TableRow.java:225)
at javafx.scene.control.IndexedCell.updateIndex(IndexedCell.java:116)
at com.sun.javafx.scene.control.skin.VirtualFlow.releaseCell(VirtualFlow.java:1807)
at com.sun.javafx.scene.control.skin.VirtualFlow.getCellLength(VirtualFlow.java:1881)
at com.sun.javafx.scene.control.skin.VirtualFlow.computeViewportOffset(VirtualFlow.java:2528)
at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1189)
at javafx.scene.Parent.layout(Parent.java:1079)
at javafx.scene.Parent.layout(Parent.java:1085)
at javafx.scene.Parent.layout(Parent.java:1085)
at javafx.scene.Parent.layout(Parent.java:1085)
at javafx.scene.Parent.layout(Parent.java:1085)
at javafx.scene.Scene.doLayoutPass(Scene.java:552)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
at com.sun.javafx.tk.Toolkit.lambda$runPulse$31(Toolkit.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:354)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:381)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:510)
at com.sun.javafx.tk.quantum.PaintCollector.liveRepaintRenderJob(PaintCollector.java:320)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$ViewEventNotification.run(GlassViewEventHandler.java:788)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$ViewEventNotification.run(GlassViewEventHandler.java:749)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleViewEvent$369(GlassViewEventHandler.java:828)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleViewEvent(GlassViewEventHandler.java:827)
at com.sun.glass.ui.View.handleViewEvent(View.java:539)
at com.sun.glass.ui.View.notifyResize(View.java:875)
at com.sun.glass.ui.win.WinWindow._setBounds(Native Method)
at com.sun.glass.ui.Window.setBounds(Window.java:572)
at com.sun.javafx.tk.quantum.WindowStage.setBounds(WindowStage.java:318)
at javafx.stage.Window$TKBoundsConfigurator.apply(Window.java:1274)
at javafx.stage.Window$TKBoundsConfigurator.pulse(Window.java:1290)
at com.sun.javafx.tk.Toolkit.lambda$runPulse$31(Toolkit.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:354)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:378)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:510)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$405(QuantumToolkit.java:319)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$149(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)

这就是它的样子。看起来，最后一个单元格试图用ChoiceBox.来适应表中的每一行。

我如何将其仅限于包含数据的行？

编辑:增刊

我现在使用的代码的一部分。

classroomChoiceBox.getSelectionModel().selectedItemProperty().addListener((obs, oldValue, newValue) -> {
        if (newValue != null) {
            processEdit(newValue);
        }
    });

@Override
public void commitEdit(Classroom value) { // always gets executed
    super.commitEdit(value);
    Student student = (Student) getTableRow().getItem();
    student.setClassroom(value);
    new StudentDao().updateStudent(student); // students get updated on creation of the table
    classroomChoiceBox.setValue(value);
    setGraphic(classroomChoiceBox);
}

问题是每个Student在创建表时都会被更新。

Answer 1

如果没有选择，则选择模型中的选定索引设置为-1 (参见文档)。由于-1不是列表中的有效索引，因此需要检查以下情况：

classroomChoiceBox.getSelectionModel().selectedIndexProperty().addListener((obs, oldValue, newValue) -> {
    int index = newValue.intValue();
    if (index >= 0) {
        Classroom value = classroomChoiceBox.getItems().get(index);

        // what is the point of the next line? 
        // surely this is the value in the choice box already???
        classroomChoiceBox.setValue(value);

        processEdit(value);
    }
});

当然，直接从选择模型中获取值可能更容易，而不是获取其索引：

classroomChoiceBox.getSelectionModel().selectedItemProperty().addListener((obs, oldValue, newValue) -> {
    if (newValue != null) { /* don't know if you care if this is null... */
        processEdit(newValue);
    }
});

在空单元格中看到选择框的原因是，在单元格的updateItem方法中，将图形显式设置为空单元格中的选择框。我假设(因为if块与else块相同)，这只是某种复制和粘贴错误。