TreeCellEditor：即使ShouldSelectCell返回false，也必须选择要编辑的单元格 [英] TreeCellEditor: must select cell to edit even if ShouldSelectCell return false

问题描述

我需要为我的JTree使用自定义单元格渲染器在每个单元格上添加一些JLabel。然后允许用户点击这些标签而无需先选择单元格。

I need to use custom cell renderer for my JTree to add some JLabel on each cell. And then allow the user to click on these label without needing to select the cell first.

所以，我创建了一个Renderer，它返回一个包含DefaultTreeCellRenderer的JPanel， 2 JLabel。

So, i've created a Renderer which return a JPanel that contains a DefaultTreeCellRenderer and 2 JLabel.

    public class TreeNodeRenderer extends DefaultTreeCellRenderer implements TreeCellRenderer
    {
        private JPanel panel1 = new JPanel();
        private JLabel delete = new JLabel("");
        private JLabel upload = new JLabel("");

        public Component getTreeCellRendererComponent(JTree tree, 
                            Object value,
                boolean selected, boolean expanded, boolean leaf, int row,
                boolean hasFocus) 
        {   
            //
            // DELETE label
            //
            delete.setName("delete");
            delete.setIcon(new ImageIcon("Data/trash.png"));

            //
            // UPLOAD label
            //
            upload.setName("upload");
            upload.setIcon(new ImageIcon("Data/app_up.png"));


            DefaultTreeCellRenderer defaultRenderer = new DefaultTreeCellRenderer();
            Color backgroundSelectionColor = defaultRenderer.getBackgroundSelectionColor();
            Color backgroundNonSelectionColor = defaultRenderer.getBackgroundNonSelectionColor();

            if(selected)
                panel1.setBackground(backgroundSelectionColor);
            else
                panel1.setBackground(backgroundNonSelectionColor);


            component = (DefaultTreeCellRenderer) super.getTreeCellRendererComponent(tree,
                    value, selected, expanded, leaf, row, hasFocus);

            panel1.add(component);
            panel1.add(delete);
            panel1.add(upload);

            return panel1;
        }
    }

然后我创建了编辑器以允许用户借助MouseListener，点击这些标签。除了用户必须在点击标签之前选择单元格外，一切都运行良好。
我尝试使用方法ShouldSelectCell返回false但它不起作用。

Then i've created the editor to allow user to click on these labels thanks to a MouseListener. Everything works well except that the user must select the cell before click on a label. I tried to return "false" with the method "ShouldSelectCell" but it doesn't work.

有人知道为什么吗？

编辑器：

public class TreeNodeEditor extends AbstractCellEditor implements TreeCellEditor
{
    private TreeNodeRenderer renderer;

    public TreeNodeEditor(TreeNodeRenderer treeRenderer)
    {
        this.renderer = treeRenderer;

    //change the cursor when it's over a label  renderer.getDeleteButton().setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
    renderer.getUploadButton().setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));       renderer.getDownloadButton().setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));

                 //add labels' mouse listeners 
        addLabelMouseListener(renderer.getDeleteButton());
        addLabelMouseListener(renderer.getUploadButton());
    }

    public Component getTreeCellEditorComponent(JTree tree, Object value, boolean isSelected, boolean expanded, boolean leaf, int row)
    {
        ...

        return renderer.getTreeCellRendererComponent(
                tree, value, isSelected,
                expanded, leaf, row, true);
    }

    public boolean isCellEditable(EventObject anEvent) 
    {
        return true;
    }

    public boolean shouldSelectCell(EventObject anEvent) 
    {
        return false;
    }


    public boolean stopCellEditing() 
    {
        return super.stopCellEditing();
    }

    public void cancelCellEditing() 
    {
        super.cancelCellEditing();
    }

    public void addCellEditorListener(CellEditorListener l)
    {
        super.addCellEditorListener(l);
    }

    public void removeCellEditorListener(CellEditorListener l) 
    {
        super.removeCellEditorListener(l);
    }

    public Object getCellEditorValue() 
    {
        return null;
    }
}

编辑 - 这是一个SSCCE：

EDIT - Here a SSCCE:

import java.awt.Color;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.EventObject;

import javax.swing.AbstractCellEditor;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.CellEditorListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeCellEditor;
import javax.swing.tree.TreeCellRenderer;



public class EditJTreeCell extends JFrame
{
    /**
     * 
     */
    private static final long serialVersionUID = 4745146614430249610L;

    private JTree tree;
    private DefaultTreeModel treeModel;
    private DefaultMutableTreeNode root;

    public EditJTreeCell()
    {
        super("Sample");
        root = new DefaultMutableTreeNode("Root folder");
        treeModel = new DefaultTreeModel(root);
        tree = new JTree(treeModel);

        TreeNodeRenderer renderer = new TreeNodeRenderer();
        tree.setCellRenderer(renderer);
        tree.setCellEditor(new TreeNodeEditor());
        tree.setEditable(true);

        //tree creation
        DefaultMutableTreeNode folder = new DefaultMutableTreeNode("folder1");
        DefaultMutableTreeNode file = new DefaultMutableTreeNode("file1");
        folder.add(file);
        file = new DefaultMutableTreeNode("file2");
        folder.add(file);
        root.add(folder);
        folder = new DefaultMutableTreeNode("folder2");
        file = new DefaultMutableTreeNode("file1");
        folder.add(file);
        file = new DefaultMutableTreeNode("file2");
        folder.add(file);
        file = new DefaultMutableTreeNode("file3");
        folder.add(file);
        root.add(folder);

        this.setSize(400, 800);
        this.add(tree);
        this.setVisible(true);
    }

    public static void main(String[] args) 
    {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (UnsupportedLookAndFeelException e) {
            e.printStackTrace();
        }
        new EditJTreeCell();
    }
}

class TreeNodeRenderer extends DefaultTreeCellRenderer implements TreeCellRenderer
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private JPanel panel1 = new JPanel();
    private JLabel delete = new JLabel("DELETE");
    private JLabel upload = new JLabel("UPLOAD");

    public Component getTreeCellRendererComponent(JTree tree, Object value,
            boolean selected, boolean expanded, boolean leaf, int row,
            boolean hasFocus) 
    {   
        //
        // DELETE label
        //
        delete.setName("delete");
        delete.setIcon(new ImageIcon("trash.png"));
        //addLabelMouseListener(delete);
        //
        // UPLOAD label
        //
        upload.setName("upload");
        upload.setIcon(new ImageIcon("app_up.png"));
        //addLabelMouseListener(upload);


        DefaultTreeCellRenderer defaultRenderer = new DefaultTreeCellRenderer();
        Color backgroundSelectionColor = defaultRenderer.getBackgroundSelectionColor();
        Color backgroundNonSelectionColor = defaultRenderer.getBackgroundNonSelectionColor();

        DefaultTreeCellRenderer component = (DefaultTreeCellRenderer) super.getTreeCellRendererComponent(tree,
                value, selected, expanded, leaf, row, hasFocus);

        if(selected)
        {   
            panel1.setBackground(backgroundSelectionColor);
        }
        else
        {
            panel1.setBackground(backgroundNonSelectionColor);
        }

        panel1.add(component);
        panel1.add(delete);
        panel1.add(upload);

        return panel1;
    }
}

class TreeNodeEditor extends AbstractCellEditor implements TreeCellEditor
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private JLabel button1;
    private JLabel button2;
    private JPanel panel1;
    private DefaultMutableTreeNode node = null;
    private DefaultTreeCellRenderer defaultRenderer;


    public TreeNodeEditor()
    {
        super();
        panel1 = new JPanel();
        defaultRenderer = new DefaultTreeCellRenderer();
        button1 = new JLabel("DELETE");
        button1.setOpaque(true);
        button1.setIcon(new ImageIcon("trash.png"));
        button1.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
        button1.addMouseListener(new MouseListener() 
        {
            public void mouseClicked(MouseEvent arg0) {
                System.out.println("Delete clicked");
            }
            public void mouseEntered(MouseEvent arg0) {}
            public void mouseExited(MouseEvent arg0) {}
            public void mousePressed(MouseEvent arg0) {}
            public void mouseReleased(MouseEvent arg0) {}

        });
        button2 = new JLabel("UPLOAD");
        button2.setOpaque(true);
        button2.setIcon(new ImageIcon("app_up.png"));
        button2.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
        button2.addMouseListener(new MouseListener() 
        {
            public void mouseClicked(MouseEvent arg0) {
                System.out.println("Upload clicked");
            }
            public void mouseEntered(MouseEvent arg0) {}
            public void mouseExited(MouseEvent arg0) {}
            public void mousePressed(MouseEvent arg0) {}
            public void mouseReleased(MouseEvent arg0) {}

        });
    }


    public Component getTreeCellEditorComponent(JTree tree, Object value, 
            boolean isSelected, boolean expanded, boolean leaf, int row)
    {
        //in order to do some actions on a node
        if(value instanceof DefaultMutableTreeNode)
        {
            node = (DefaultMutableTreeNode) value;
        }


         defaultRenderer.getTreeCellRendererComponent(tree,
                    value, isSelected, expanded, leaf, row, true);

        panel1.add(defaultRenderer);
        panel1.add(button1);
        panel1.add(button2);
        return panel1;
    }

    public boolean isCellEditable(EventObject anEvent) 
    {
        return true;
    }

    public boolean shouldSelectCell(EventObject anEvent) 
    {
        return false;
    }


    public boolean stopCellEditing() 
    {
        return super.stopCellEditing();
    }

    public void cancelCellEditing() 
    {
        super.cancelCellEditing();
    }

    public void addCellEditorListener(CellEditorListener l)
    {
        super.addCellEditorListener(l);
    }

    public void removeCellEditorListener(CellEditorListener l) 
    {
        super.removeCellEditorListener(l);
    }

    public Object getCellEditorValue() 
    {
        return null;
    }
}

推荐答案

开始对mouseEnter的编辑是一个有效的解决方案： - ）

starting an edit on mouseEnter is a valid solution :-)

另一方面，你的编辑器不是一个有效的实现：如果编辑的话，它就不会通知它的监听器由于内部事件而终止（如点击任何按钮）以下是如何实现目标并拥有有效实施的示例

Your editor, on the other hand is not a valid implementation: it fails on not notifying its listener if the edit is terminated due to internal events (as f.i. clicking on any of the buttons) Below is an example of how-to achieve both your goal and have a valid implementation

几个评论：

• 如果你想要一个像按钮这样的东西..使用按钮：否则用户可能会感到困惑


• 在您的编辑器中，根据需要为按钮设置操作


• 在构造函数中执行所有基本面板配置（如添加其子项））


• 开始编辑/检测单击了哪个按钮，重新调度在shouldSelect中收到的事件。在SwingUtilities.invokeLater中执行此操作以确保任何内部挂起的事件（在树中）已准备就绪


• 不要更改编辑器中的树节点：a）这些更改将无法通知模型b）将被树的默认编辑终止行为否决。 DefaultTreeTable将使用editorValue重置树的userObject，这是在valueForPathChanged中完成的：实现自定义行为，在模型中覆盖该方法

• if you want something like a button .. use a button: otherwise users might be confused
• in your editor, set an action to the buttons as needed
• do all basic panel config (like adding its children) in the constructor)
• to start editing/detect which button is clicked, re-dispatch the event received in shouldSelect. Do it in a SwingUtilities.invokeLater to make sure any internally pending events (in the tree) are ready
• do not change the tree node inside the editor: a) those changes will fail to notify the model b) will be overruled by the tree's default editing termination behaviour. DefaultTreeTable will reset the userObject of the tree with editorValue, that's done in valueForPathChanged: to implement custom behaviour, override that method in the model

在代码中：

static class TreeNodeEditor extends AbstractCellEditor implements TreeCellEditor {
    private static final long serialVersionUID = 1L;
    private JButton button1;
    private JButton button2;
    private JPanel panel1;
    // JW: do not modify the node inside the editor 
    //        private DefaultMutableTreeNode node = null;
    private DefaultTreeCellRenderer defaultRenderer;

    private Object editorValue;

    public TreeNodeEditor() {
        super();
        panel1 = new JPanel();
        defaultRenderer = new DefaultTreeCellRenderer();
        button1 = new JButton("DELETE");
        button1.setOpaque(true);
        button1.setIcon(new ImageIcon("trash.png"));
        button1.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
        button2 = new JButton("UPLOAD");
        button2.setOpaque(true);
        button2.setIcon(new ImageIcon("app_up.png"));
        button2.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
        button2.setAction(createAction("upload", "UPLOAD"));
        button1.setAction(createAction("delete", "DELETE"));
        panel1.add(defaultRenderer);
        panel1.add(button1);
        panel1.add(button2);
    }

    private Action createAction(final String actionCommand, String display) {
        Action action = new AbstractAction(display) {

            @Override
            public void actionPerformed(ActionEvent e) {
                stopEditing(actionCommand);
            }

        };
        return action;

    }
    /**
     * @param actionCommand
     */
    protected void stopEditing(String actionCommand) {
        editorValue = actionCommand;
        stopCellEditing();
    }

    @Override
    public Component getTreeCellEditorComponent(JTree tree, Object value,
            boolean isSelected, boolean expanded, boolean leaf, int row) {
        // in order to do some actions on a node
        //            if (value instanceof DefaultMutableTreeNode) {
        //                node = (DefaultMutableTreeNode) value;
        //            }

        defaultRenderer.getTreeCellRendererComponent(tree, value,
                isSelected, expanded, leaf, row, true);

        return panel1;
    }

    /**
     * 
     */
    private void reset() {
        editorValue = null;
    }

    /**
     * At this point in time the component is added to the tree (not documented!) but
     * tree's internal cleanup might not yet be ready
     */ 
    @Override
    public boolean shouldSelectCell(EventObject anEvent) {
        reset();
        if (anEvent instanceof MouseEvent) {
            redirect((MouseEvent) anEvent);
        }
        return false;
    }

    private void redirect(final MouseEvent anEvent) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                MouseEvent ev = SwingUtilities.convertMouseEvent(anEvent.getComponent(), anEvent, panel1);
                panel1.dispatchEvent(ev);

            }
        });
    }

    @Override
    public Object getCellEditorValue() {
        return editorValue;
    }
}

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