Question

在java-9中，Skins将其置于公共范围内，而行为则处于黑暗状态 - 尽管如此，现在使用InputMap对所有输入绑定进行了相当大的改动。

CellBehaviorBase安装鼠标绑定，如：

InputMap.MouseMapping pressedMapping, releasedMapping;
addDefaultMapping(
    pressedMapping = new InputMap.MouseMapping(MouseEvent.MOUSE_PRESSED, this::mousePressed),
    releasedMapping = new InputMap.MouseMapping(MouseEvent.MOUSE_RELEASED, this::mouseReleased),
    new InputMap.MouseMapping(MouseEvent.MOUSE_DRAGGED, this::mouseDragged)
);

具体的XXSkin现在私下安装行为：

final private BehaviorBase behavior; 
public TableCellSkin(TableCell control) {
    super(control);
    behavior = new TableCellBehavior(control);
    .... 
}

要求是替换mousePressed行为（在jdk9上下文中）。我们的想法是反思地抓住超级领域，处理所有映射并安装自定义行为。出于某种原因，我不明白，旧的绑定仍然是活动的（虽然旧映射是空的！）并且在新绑定之前调用。

下面是一个可以运行的可运行示例：只是实现了对mousePressed的映射，什么都不做，特别是不调用super。要查看旧的绑定，我在CellBehaviorBase.mousePressed中设置一个条件调试断点（在Eclipse中）：

System.out.println("mousePressed super"); new RuntimeException("whoIsCalling: " + getNode().getClass()).printStackTrace(); return false;

运行调试并单击进入任何单元格，然后输出为：

mousePressed super java.lang.RuntimeException: whoIsCalling: class de.swingempire.fx.scene.control.cell.TableCellBehaviorReplace$PlainCustomTableCell at com.sun.javafx.scene.control.behavior.CellBehaviorBase.mousePressed(CellBehaviorBase.java:169) at com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274) at com.sun.javafx.event.CompositeEventHandler$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) //... lots more of event dispatching // until finally the output in my custom cell behavior Feb. 02, 2016 3:14:02 NACHM. de.swingempire.fx.scene.control.cell.TableCellBehaviorReplace$PlainCustomTableCellBehavior mousePressed INFORMATION: short-circuit super: Bulgarisch

我希望只看到最后一部分，即我的自定义行为的打印输出。感觉就像我在某种程度上从根本上断了 - 但不能指出它。想法？

可运行的代码（对不起它的长度，大多数是锅炉板）：

public class TableCellBehaviorReplace extends Application { private final ObservableList<Locale> locales = FXCollections.observableArrayList(Locale.getAvailableLocales()); private Parent getContent() { TableView<Locale> table = createLocaleTable(); BorderPane content = new BorderPane(table); return content; } private TableView<Locale> createLocaleTable() { TableView<Locale> table = new TableView<>(locales); TableColumn<Locale, String> name = new TableColumn<>("Name"); name.setCellValueFactory(new PropertyValueFactory<>("displayName")); name.setCellFactory(p -> new PlainCustomTableCell<>()); TableColumn<Locale, String> lang = new TableColumn<>("Language"); lang.setCellValueFactory(new PropertyValueFactory<>("displayLanguage")); lang.setCellFactory(p -> new PlainCustomTableCell<>()); table.getColumns().addAll(name, lang); return table; } /** * Custom skin that installs custom Behavior. Note: this is dirty! * Access super's behavior, dispose to get rid off its handlers, install * custom behavior. */ public static class PlainCustomTableCellSkin<S, T> extends TableCellSkin<S, T> { private BehaviorBase<?> replacedBehavior; public PlainCustomTableCellSkin(TableCell<S, T> control) { super(control); replaceBehavior(); } private void replaceBehavior() { BehaviorBase<?> old = (BehaviorBase<?>) invokeGetField(TableCellSkin.class, this, "behavior"); old.dispose(); // at this point, InputMap mappings are empty: // System.out.println("old mappings: " + old.getInputMap().getMappings().size()); replacedBehavior = new PlainCustomTableCellBehavior<>(getSkinnable()); } @Override public void dispose() { replacedBehavior.dispose(); super.dispose(); } } /** * Custom behavior that's meant to override basic handlers. Here: short-circuit * mousePressed. */ public static class PlainCustomTableCellBehavior<S, T> extends TableCellBehavior<S, T> { public PlainCustomTableCellBehavior(TableCell<S, T> control) { super(control); } @Override public void mousePressed(MouseEvent e) { if (true) { LOG.info("short-circuit super: " + getNode().getItem()); return; } super.mousePressed(e); } } /** * C&P of default tableCell in TableColumn. Extended to install custom * skin. */ public static class PlainCustomTableCell<S, T> extends TableCell<S, T> { public PlainCustomTableCell() { } @Override protected void updateItem(T item, boolean empty) { if (item == getItem()) return; super.updateItem(item, empty); if (item == null) { super.setText(null); super.setGraphic(null); } else if (item instanceof Node) { super.setText(null); super.setGraphic((Node)item); } else { super.setText(item.toString()); super.setGraphic(null); } } @Override protected Skin<?> createDefaultSkin() { return new PlainCustomTableCellSkin<>(this); } } @Override public void start(Stage primaryStage) throws Exception { primaryStage.setScene(new Scene(getContent(), 400, 200)); primaryStage.setTitle(FXUtils.version()); primaryStage.show(); } public static void main(String[] args) { launch(args); } /** * Reflectively access super field. */ public static Object invokeGetField(Class source, Object target, String name) { try { Field field = source.getDeclaredField(name); field.setAccessible(true); return field.get(target); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) { e.printStackTrace(); } return null; } @SuppressWarnings("unused") private static final Logger LOG = Logger .getLogger(TableCellBehaviorReplace.class.getName()); }

修改

建议继承自抽象皮肤XXSkinBase而不是具体的XXSkin （然后你可以自由安装你想要的任何行为，dude :-)是非常合理的，应该是第一个选择。在特定情况下，XX是TableCell，即currently not possible，因为基类包含抽象包私有方法。此外，还有XX没有抽象基础（如f.i. ListCell）。

Answer 1

可能是InputMap中的错误：

深入研究我发现了一些与映射并行的内部簿记（eventTypeMappings）（这些是处理程序）。 InputMap正在监听映射中的更改并更新内部记录更改

mappings.addListener((ListChangeListener<Mapping<?>>) c -> {
    while (c.next()) {
        // TODO handle mapping removal
        if (c.wasRemoved()) {
            for (Mapping<?> mapping : c.getRemoved()) {
                removeMapping(mapping);
            }
        }

// removeMapping
private void removeMapping(Mapping<?> mapping) {
    // TODO
}

意味着永远不会清除内部结构，尤其是在behavior.dispose()中删除映射时。在查找eventHandlers时 - 通过inputMap.handle(e)，请参阅问题中显示的调试堆栈跟踪 - 在内部簿记结构中找到旧处理程序。

早期实验的乐趣......; - ）

最后，一个（非常肮脏，非常hacky！）解决方案是接管InputMap的工作并强制清理内部：

private void replaceBehavior() {
    BehaviorBase<?> old = (BehaviorBase<?>) invokeGetField(TableCellSkin.class, this, "behavior");
    old.dispose();
    cleanupInputMap(old.getInputMap());
    // at this point, InputMap mappings are empty:
    // System.out.println("old mappings: " + old.getInputMap().getMappings().size());
    replacedBehavior = new PlainCustomTableCellBehavior<>(getSkinnable());
}

/**
 * This is a hack around InputMap not cleaning up internals on removing mappings.
 * We remove MousePressed/MouseReleased/MouseDragged mappings from the internal map.
 * Beware: obviously this is dirty!
 * 
 * @param inputMap
 */
private void cleanupInputMap(InputMap<?> inputMap) {
    Map eventTypeMappings = (Map) invokeGetField(InputMap.class, inputMap, "eventTypeMappings");
    eventTypeMappings.remove(MouseEvent.MOUSE_PRESSED);
    eventTypeMappings.remove(MouseEvent.MOUSE_RELEASED);
    eventTypeMappings.remove(MouseEvent.MOUSE_DRAGGED);
}

BTW：以防任何人想知道wtf - 没有，当我编辑一个在java-9中停止工作的单元时，我在缺少commitOnFocusLost的周围。

Answer 2

尝试从PlainCustomTableCellSkin继承抽象类TableCellSkinBase而不是TableCellSkin。然后你可以调用超级构造函数，它将TableCellBehaviorBase对象作为附加参数。然后你可以节省你的时间来替换它，直接用正确的方法初始化它。

只是为了更多的鼓励： TableCellSkin扩展了TableCellSkinBase TableCellBehavior扩展了TableCellBehaviorBase

还有一件事。您还需要在构造函数中调用super.init（tableCell）。以TableCellSkin类为参考。

如何覆盖已安装的行为映射？

2 个答案: