Question

问题如下：

我有一个TableView和一个ComboBoxes，我可以为每个TableCell选择组合框中的值。问题是，如果我有很多行和列，我必须单击很多以在每个comboBox中选择适当的值。要在组合框中选择一个值，我必须单击四次以选择该值。一次选择单元格，一次设置组合框的图形，再次打开组合框的弹出窗口，我可以在其中选择值，最后选择值。

我想使用doubleClick，因此我可以快速打开comboBox，然后选择值。如果我要选择的值很多，这将节省点击次数和很多时间。

我试图解决它，但是所有解决方案都无法正常工作，

我在这里添加了它们，也许您可以看到我出了错的地方并进行纠正。

我尝试了两种类似的方法：

忽略startEdit（）并将鼠标单击侦听器添加到单元格，然后双击双击组合框。如果我单击另一个单元格，即使我同时将setGrapichs(null)和cancelEdit都放在commitEdit上，单击上一个单元格也不会将图形设置为null，这会带来问题。另一个问题是有时不将值提交给模型。

第二种方法是在startEdit（）中处理它，因此只需根据操作在其中调用.show()并在提交和取消编辑中调用.hide()即可。这给了我NPE，如果我将TableView包裹在TitledPane中，然后折叠/展开它，则尝试选择一个值，双击它会得到NPE：

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.ComboBoxPopupControl.positionAndShowPopup(ComboBoxPopupControl.java:197)
at com.sun.javafx.scene.control.skin.ComboBoxPopupControl.show(ComboBoxPopupControl.java:170)
at com.sun.javafx.scene.control.skin.ComboBoxBaseSkin.handleControlPropertyChanged(ComboBoxBaseSkin.java:127)
at com.sun.javafx.scene.control.skin.ComboBoxListViewSkin.handleControlPropertyChanged(ComboBoxListViewSkin.java:159)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$registerChangeListener$61(BehaviorSkinBase.java:197)
at com.sun.javafx.scene.control.MultiplePropertyChangeListenerHandler$1.changed(MultiplePropertyChangeListenerHandler.java:55)
at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:89)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:182)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.ReadOnlyBooleanPropertyBase.fireValueChangedEvent(ReadOnlyBooleanPropertyBase.java:72)
at javafx.beans.property.ReadOnlyBooleanWrapper.fireValueChangedEvent(ReadOnlyBooleanWrapper.java:103)
at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:144)
at javafx.scene.control.ComboBoxBase.setShowing(ComboBoxBase.java:185)
at javafx.scene.control.ComboBoxBase.show(ComboBoxBase.java:391)
at stackoverflow.combo.ComboTableCell.startEdit(ComboTableCell.java:47)
at javafx.scene.control.TableCell.updateEditing(TableCell.java:556)
at javafx.scene.control.TableCell.lambda$new$26(TableCell.java:142)
at javafx.beans.WeakInvalidationListener.invalidated(WeakInvalidationListener.java:83)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:349)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.ReadOnlyObjectPropertyBase.fireValueChangedEvent(ReadOnlyObjectPropertyBase.java:74)
at javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:102)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
at javafx.scene.control.TableView.setEditingCell(TableView.java:1145)
at javafx.scene.control.TableView.edit(TableView.java:1459)
at com.sun.javafx.scene.control.behavior.TableCellBehavior.edit(TableCellBehavior.java:108)
at com.sun.javafx.scene.control.behavior.TableCellBehavior.edit(TableCellBehavior.java:38)
at com.sun.javafx.scene.control.behavior.CellBehaviorBase.handleClicks(CellBehaviorBase.java:271)
at com.sun.javafx.scene.control.behavior.TableCellBehaviorBase.simpleSelect(TableCellBehaviorBase.java:218)
at com.sun.javafx.scene.control.behavior.TableCellBehaviorBase.doSelect(TableCellBehaviorBase.java:148)
at com.sun.javafx.scene.control.behavior.CellBehaviorBase.mouseReleased(CellBehaviorBase.java:159)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)

这是您可以检查的代码：

TableCell：

public class ComboTableCell<T,S> extends TableCell<T,S> {

    private ComboBox<S> combo;

    public ComboTableCell(Collection<S> items) {
        combo = new ComboBox<>();
        combo.setItems(FXCollections.observableArrayList(items));
        combo.prefWidthProperty().bind(widthProperty());
        combo.valueProperty().addListener((observable, oldValue, newValue) -> commitEdit(newValue));
//      1. Solution with mouse event
//      this.setOnMouseClicked(event -> {
//          if(event.getClickCount() == 2){
//              combo.getSelectionModel().select(getItem());
//              setText(null);
//              setGraphic(combo);
//              if(!combo.isShowing()){
//                  combo.show();
//              }
//          }
//      });
    }

//  2. Solution with startEdit
    @Override
    public void startEdit() {
        combo.getSelectionModel().select(getItem());
        super.startEdit();
        setText(null);
        setGraphic(combo);
        if(!combo.isShowing()){
            combo.show();
        }
    }

    @Override
    protected void updateItem(S item, boolean empty) {
        super.updateItem(item, empty);
        if(empty){
            setText(null);
            setGraphic(null);
            return;
        }
        setText(getItem().toString());
        setGraphic(null);
    }

    @Override
    public void cancelEdit() {
        super.cancelEdit();
        setText(getItem().toString());
        setGraphic(null);
        if(combo.isShowing()){
            combo.hide();
        }
    }

    @Override
    public void commitEdit(S newValue) {
        super.commitEdit(newValue);
        setGraphic(null);
        setText(getItem().toString());
        if(combo.isShowing()){
            combo.hide();
        }
        setGraphic(null);
        setText(getItem().toString());
    }
}

控制器：

public class Controller implements Initializable {

    @FXML
    private TableView<Model> table;
    @FXML
    private TableColumn<Model,String> col;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        table.setEditable(true);

        col.setCellValueFactory(data -> data.getValue().text);
        col.setCellFactory(factory -> new ComboTableCell<>(Arrays.asList("a","b","c")));

        table.setItems(FXCollections.observableArrayList(Arrays.asList(new Model("a"),new Model("b"))));
    }

     static class Model{

        private StringProperty text;

        public Model(String text) {
            this.text = new SimpleStringProperty(text);
        }

        public String getText() {
            return text.get();
        }

        public StringProperty textProperty() {
            return text;
        }
    }

}

Fxml：

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TitledPane?>
<AnchorPane xmlns="http://javafx.com/javafx"
            xmlns:fx="http://javafx.com/fxml"
            fx:controller="stackoverflow.combo.Controller">
    <TitledPane text="Table">
        <TableView fx:id="table">
            <columns>
                <TableColumn fx:id="col" prefWidth="200"/>
            </columns>
        </TableView>
    </TitledPane>
</AnchorPane>

我希望使用能为我提供预期结果的任何解决方案，您甚至可以建议我使用其他解决方案，该解决方案使用的解决方法较少，或者为我建议的“解决方案”之一进行了修复。

JDK版本 1.8.0_121

Answer 1

我在使用方法（2）时遇到了相同的问题，单击时我的状态为以下情况。出现comboBox，但不会扩展。进一步单击将不会触发任何操作。

最后，我在comboBox上实现了焦点侦听器，该侦听器将在焦点显示时显示弹出窗口。我在requestFocus的结尾打了startEdit。

// In the creation of comboBox, add focus listener
combo.focusProperty().addListener((observable, oldValue, isFocused) -> if (isFocused) combo.show());

@Override
public void startEdit() {
    combo.getSelectionModel().select(getItem());
    super.startEdit();
    setText(null);
    setGraphic(combo);
    // Creating a JavaFX task to make a small delay and then request focus.
    // Code below is in Kotlin and TornadoFX, but you get the point.
    runAsync {
        Thread.sleep(50)
    } ui {
        combo.requestFocus()
    }
}

上述延迟是comboBox正确绘制其布局所必需的。否则，根据布局是否已更新，您将随机遇到以下情况。

在这么小的延迟下，您将一直得到正确的显示。

P.S。如果您在考虑，为什么不只是在短暂的延迟后直接调用comboBox.show（）并删除focusListener？好吧，在我的测试中，当您创建新行或调用table.refresh（）时，comboBox只是无法随机显示（类似于第一张图片）。我想这与virtualFlow和为同一实例创建的tableCell的多个实例有关。参见here。

JavaFx：组合框表单元格双击

1 个答案: