动态更改JTree中特定节点的图标 [英] Dynamically change icon of specific nodes in JTree

问题描述

我已经看到很多在树实例化期间更改节点图标的示例，但我想要一种方法来稍后动态更改单个节点的图标。因此，在我的主代码中，我将自定义渲染器添加到我的树中：

I've seen plenty of examples for changing the icon of nodes during tree instantiation, but I'd like a way to dynamically change the icon of an individual node later. So, in my main code I add my custom renderer to my tree:

// Icon I want to set nodes to later
ImageIcon checkIcon = new ImageIcon("check.jpg");

// Creates tree with my nodes
JTree tree = new JTree(nodes.top);

// Create custom renderer
Scenario1Renderer renderer = new Scenario1Renderer();

// Set to single tree selection 
tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

// Set tree to my custom renderer
//renderer.setRendererIcon(greenIcon);
tree.setCellRenderer(renderer);

我在渲染器中的代码是

public class Scenario1Renderer extends DefaultTreeCellRenderer {

ImageIcon rendererIcon;

    public void setRendererIcon(ImageIcon myIcon){
      this.rendererIcon = myIcon;
    };

public Component getTreeCellRendererComponent( 
         JTree tree, 
         Object value, 
         boolean sel, 
         boolean expanded, 
         boolean leaf, 
         int row, 
         boolean hasFocus)
{ 

    Component ret = super.getTreeCellRendererComponent(tree, value,
            selected, expanded, leaf, row, hasFocus);
            //setIcon( rendererIcon ) ;
            return ret;
    } 

所以，很明显，如果我设置我的rendererIcon，它会绘制我的所有节点我在树实例化过程中传入的图标。我想要某种方法，可以在我的程序执行中稍后设置单个节点的图标。

So, obviously if I set my rendererIcon, it'll paint all my nodes with the icon I pass in during tree instantiation. I instead want some sort of method that can set the icon of an individual node later on in the execution of my program.

推荐答案

您可以根据不同的条件设置不同的图标。下面是一个更改所选节点图标的简单示例：

You can have different icons that you can set according to different conditions. Below is a simple example that changes icon of a selected node:

import java.awt.Component;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;

public class TestTree {
    private static void createAndShowUI() {
        JFrame frame = new JFrame();
        final JTree tree = new JTree(buildDemoModel());

        tree.setCellRenderer(new DefaultTreeCellRenderer() {
            private Icon loadIcon = UIManager.getIcon("OptionPane.errorIcon");
            private Icon saveIcon = UIManager.getIcon("OptionPane.informationIcon");
            @Override
            public Component getTreeCellRendererComponent(JTree tree,
                    Object value, boolean selected, boolean expanded,
                    boolean isLeaf, int row, boolean focused) {
                Component c = super.getTreeCellRendererComponent(tree, value,
                        selected, expanded, isLeaf, row, focused);
                if (selected)
                    setIcon(loadIcon);
                else
                    setIcon(saveIcon);
                return c;
            }
        });
        tree.setVisibleRowCount(10);
        frame.add(new JScrollPane(tree));

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);
        frame.pack();
        frame.setVisible(true);
    }

    private static DefaultTreeModel buildDemoModel() {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");

        root.add(new DefaultMutableTreeNode("A"));
        root.add(new DefaultMutableTreeNode("B"));
        root.add(new DefaultMutableTreeNode("C"));

        return new DefaultTreeModel(root);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                createAndShowUI();
            }
        });
    }
}

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