JavaFX:向嵌套 CheckBoxTreeItem[s] 的复选框添加 CTRL 单击功能

Question

我有一种情况，正在显示一个 TreeView，有两个级别的条目(父级和子级)，如下所示:

root (invisible)
|_ parent item 1
   |_ child item 1-1
   |_ child item 1-2
|_ parent item 2
   |_ child item 2-1

这些项目都是标准的CheckBoxTreeItem。我想要做的是，根据某些功能，按住 CTRL 键单击父项的复选框来选择一组子项。例如，在这里我可能只想在按 CTRL- 时选择每个子列表中的第一个子项目(即 child item 1-1 和 child item 2-1)单击父复选框。

这可能吗？ 据我所知，没有很好的方法来访问该复选框并给出例如onMouseClick 事件处理程序，这对我来说是有意义的解决方案。

上面给出的示例树布局的代码:

TreeViewTest.java

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.CheckBoxTreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.control.cell.CheckBoxTreeCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class TreeViewTest extends Application {

    @Override
    public void start(final Stage stage) {
        StackPane sceneRoot = new StackPane();

        // create the tree model
        CheckBoxTreeItem<String> parent1 = new CheckBoxTreeItem<>("parent 1");
        CheckBoxTreeItem<String> parent2 = new CheckBoxTreeItem<>("parent 2");
        CheckBoxTreeItem<String> child1_1 = new CheckBoxTreeItem<>("child 1-1");
        CheckBoxTreeItem<String> child1_2 = new CheckBoxTreeItem<>("child 1-2");
        CheckBoxTreeItem<String> child2_1 = new CheckBoxTreeItem<>("child 2-1");
        CheckBoxTreeItem<String> root = new CheckBoxTreeItem<>("root");

        // attach the nodes
        parent1.getChildren().addAll(child1_1, child1_2);
        parent2.getChildren().addAll(child2_1);
        root.getChildren().addAll(parent1, parent2);

        // display everything
        root.setExpanded(true);
        parent1.setExpanded(true);
        parent2.setExpanded(true);

        // create the treeView
        final TreeView<String> treeView = new TreeView<>();
        treeView.setShowRoot(false);
        treeView.setRoot(root);

        // set the cell factory
        treeView.setCellFactory(CheckBoxTreeCell.forTreeView());

        // display the tree
        sceneRoot.getChildren().addAll(treeView);
        Scene scene = new Scene(sceneRoot, 200, 200);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        Main.launch(args);
    }
}

Answer 1

您需要 TreeCell 的自定义实现。这应该为您提供一个起点，允许您实现所需的附加功能:

public class MyCheckBoxCell extends TreeCell<String> {

    private final CheckBox checkBox = new CheckBox();

    private BooleanProperty currentSelectedBinding ;

    // only need this if you are using the indeterminateProperty() of your
    // CheckBoxTreeItems
    private BooleanProperty currentIndeterminateBinding ;

    public MyCheckBoxCell() {

        // add extra event handling to the check box here...

    }

    @Override
    protected void updateItem(String item, boolean empty) {

        super.updateItem(item, empty);

        if (empty) {
            setText(null);
            setGraphic(null);
        } else {
            setText(item);
            setGraphic(checkBox);
            if (currentSelectedBinding != null) {
                checkBox.selectedProperty().unbindBidirectional(currentSelectedBinding);
            }
            if (currentIndeterminateBinding != null) {
                checkBox.indeterminateProperty().unbindBidirectional(currentIndeterminateBinding);
            }
            if (getTreeItem() instanceof CheckBoxTreeItem) {
                CheckBoxTreeItem cbti = (CheckBoxTreeItem<?>) getTreeItem();
                currentSelectedBinding = cbti.selectedProperty();
                checkBox.selectedProperty().bindBidirectional(currentSelectedBinding);
                currentIndeterminateBinding = cbti.indeterminateProperty();
                checkBox.indeterminateProperty().bindBidirectional(currentIndeterminateBinding);
            }
        }
    }
}