JTree 默认图标未使用根图标删除

Question

我知道google上有关于JTree图标更改的相关资料，但我仍然无法理清我的简单需求。

我需要更改 JTree 的

Root

元素的图标，使其与

node

和

leaf

不同。 我设法更改节点和叶子图标，但默认箭头图标（图中红色突出显示）仍然存在，我必须单击它才能向下钻取树，而我想单击自定义图像图标以向下钻取树.

    /** CHANGE JTREE DEFAULT ICONS  **/
        private class userRendererForTree extends DefaultTreeCellRenderer {
            private static final long serialVersionUID = 1L;
    
            public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded,
                    boolean leaf, int row, boolean hasFocus) {
    
                super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
                if (leaf) {
                    setIcon(setImageIcon(AppConstants.BOM_ROUTE_NODE_LEAF));
                } else {
                    setIcon(setImageIcon(AppConstants.BOM_ROUTE_NODE_RIGHT));
                }
                if (expanded) {
                    setIcon(setImageIcon(AppConstants.BOM_ROUTE_NODE_BOTTOM));
                }
                return this;
            }
        }

/**  LOAD IMAGE ICON FROM RESOURCES  **/
    private ImageIcon setImageIcon(String path){
        Image image = null;
        ImageIcon icon = null;
        try {
            image = LoadResource.getImageFromResourceAsURL(path);
            image = image.getScaledInstance(10, 10, Image.SCALE_SMOOTH);
            icon = new ImageIcon(image);
            return icon;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return icon;
    }

渲染器的调用：-

JTree BomTree = new JTree(createTreeModel());
scrollPane.setColumnHeaderView(BomTree);
BomTree.setCellRenderer(new userRendererForTree());

更新-

Answer 1

我很抱歉，你的意思是你想要替换展开/折叠手柄，而不是自定义单元格的展开/关闭图标......因为

JTree

并不令人困惑🙄

为此，您需要提供自己的外观实现或自定义现有的 UI 属性。

感谢 TrashGod，第二种方法相对简单，只需记住，这会影响应用程序中的所有

JTree

。

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;

public class Main {
    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.put("Tree.expandedIcon", new ImageIcon(ImageIO.read(getClass().getResource("/images/icons8-expand-arrow-24.png"))));
                    UIManager.put("Tree.collapsedIcon", new ImageIcon(ImageIO.read(getClass().getResource("/images/icons8-collapse-arrow-24.png"))));

                    JFrame frame = new JFrame();
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() throws IOException {
            setLayout(new BorderLayout());
            JTree tree = new JTree();
            tree.setShowsRootHandles(true);

            List<Item> items = new ArrayList<>(8);
            items.add(new Item("Bowle",
                    new Item[]{
                        new Item("Apple"),
                        new Item("Pear"),
                        new Item("Orangle")
                    }));
            items.add(new Item("Freezer",
                    new Item[]{
                        new Item("Top draw", new Item[]{
                            new Item("Chicken"),
                            new Item("Steak"),
                            new Item("Fish")}),
                        new Item("Bottom draw", new Item[]{
                            new Item("Pears"),
                            new Item("Chips"),
                            new Item("Ice cream")})
                    }));

            DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("My stuff");
            for (Item item : items) {
                populate(rootNode, item);
            }
            DefaultTreeModel model = new DefaultTreeModel(rootNode);
            tree.setModel(model);
            tree.setCellRenderer(new ItemTreeCellRenderer());

            add(new JScrollPane(tree));
        }

        protected void populate(DefaultMutableTreeNode parent, Item item) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(item);
            parent.add(node);

            for (Item child : item.getContents()) {
                populate(node, child);
            }
        }
    }

    class ItemTreeCellRenderer extends DefaultTreeCellRenderer {
        @Override
        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
            if (value instanceof DefaultMutableTreeNode) {
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
                Object userValue = node.getUserObject();
                if (userValue instanceof Item) {
                    Item item = (Item) userValue;
                    value = item.getName();
                }
            }
            return super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
        }
    }

    public class Item {
        private String name;
        private List<Item> contents;

        public Item(String name) {
            this.name = name;
            this.contents = new ArrayList<>(8);
        }

        public Item(String name, Item[] children) {
            this.name = name;
            this.contents = new ArrayList<>(Arrays.asList(children));
        }

        public String getName() {
            return name;
        }

        public List<Item> getContents() {
            return contents;
        }
    }
}