Question

我知道如何在JTree中设置自定义叶子图标
我知道如何为所有群组节点设置自定义关闭/打开图标

但是我不能根据组节点名称设置自定义打开/关闭图标，例如节点可以称为电子邮件（因此有一个包络图标很好）或者一组可能被称为任务等等。

我试图通过覆盖类getTreeCellRendererComponent的{{1}}方法

但更改当前DefaultTreeCellRenderer的{{1}}只会影响下一个节点！

如何为各个组设置自定义打开/关闭图标？

请查看我的代码：

的 Employee.java 的

icon

的 CustomTreeNode.java 的

node

的 CustomeTreeCellRenderer.java 的

package com.ehsunbehravesh.swing;

import java.util.Random;

public class Employee {

  public String name;
  public int id;
  public boolean isBoss;
  public Employee[] employees;

  public Employee(String name, boolean isBoss) {
    this.name = name;
    this.isBoss = isBoss;
    this.id = new Random(System.currentTimeMillis()).nextInt(Integer.MAX_VALUE);
  }  

  @Override
  public String toString() {
    return this.name;
  }

    static String randomName() {
    String chars = "abcdefghijklmnopqrstuvwxyz";
    StringBuilder builder = new StringBuilder();
    Random r = new Random(System.currentTimeMillis());
    int length = r.nextInt(10) + 1;
    for (int i = 0; i < length; i++) {
      builder.append(chars.charAt(r.nextInt(chars.length())));
    }

    return builder.toString();
  }
}

的 Test1.java 的

package com.ehsunbehravesh.swing;

import javax.swing.ImageIcon;
import javax.swing.tree.DefaultMutableTreeNode;

public class CustomTreeNode extends DefaultMutableTreeNode {

  /**
   * The icon which is displayed on the JTree object. open, close, leaf icon.
   */
  private ImageIcon icon;

  public CustomTreeNode(ImageIcon icon) {
    this.icon = icon;
  }

  public CustomTreeNode(ImageIcon icon, Object userObject) {
    super(userObject);
    this.icon = icon;
  }

  public CustomTreeNode(ImageIcon icon, Object userObject, boolean allowsChildren) {
    super(userObject, allowsChildren);
    this.icon = icon;
  }

  public ImageIcon getIcon() {
    return icon;
  }

  public void setIcon(ImageIcon icon) {
    this.icon = icon;
  }    
}

Answer 1

在TreeCellRenderer中，您可以根据需要使用setOpenIcon()和setClosedIcon()以及与您的模型相关的已定义参数和谓词。如果树具有默认的JTree模型，则下面的TreeRenderer将使用closed节点的open和sports图标：

iamge

private static class TreeRenderer extends DefaultTreeCellRenderer {

    private static final Icon closed =
        (Icon) UIManager.get("InternalFrame.maximizeIcon");
    private static final Icon open =
        (Icon) UIManager.get("InternalFrame.minimizeIcon");

    @Override
    public Component getTreeCellRendererComponent(JTree tree, Object value,
        boolean sel, boolean exp, boolean leaf, int row, boolean hasFocus) {
        DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
        String s = node.getUserObject().toString();
        if ("sports".equals(s)) {
            setOpenIcon(open);
            setClosedIcon(closed);
        } else {
            setOpenIcon(getDefaultOpenIcon());
            setClosedIcon(getDefaultClosedIcon());
        }
        super.getTreeCellRendererComponent(
            tree, value, sel, exp, leaf, row, hasFocus);
        return this;
    }
}

另请参阅此相关example。

Answer 2

运行代码之后，您尝试加载的图像似乎“意味着”嵌入到您的应用程序中（也就是说，它们不会驻留在应用程序上下文的磁盘外的某些位置）

所以不要这样做......

CustomTreeNode root = new CustomTreeNode(new ImageIcon("images/Circle_3.gif"), bigBoss);

尝试做这样的事情......

CustomTreeNode root = new CustomTreeNode(new ImageIcon(ImageIO.read(getClass().getResource("/images/Circle_3.gif"))), bigBoss);

相反。这将使Java在其类路径（包括任何JAR资源）中查找以查找图像。

当我运行没有此修复程序的代码时，没有任何工作，当我更新它以使用此功能时，它工作正常。

注意：ImageIO#read会抛出IOException所以请注意它

<强>更新

经过多次刮擦......我将细胞渲染器更改为这样......

class CustomeTreeCellRenderer extends DefaultTreeCellRenderer {

    public CustomeTreeCellRenderer() {
    }

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

//            if (!leaf) {
        CustomTreeNode node = (CustomTreeNode) value;

        if (node.getIcon() != null) {
            System.out.println(node + " - " + node.getIcon());
            setClosedIcon(node.getIcon());
            setOpenIcon(node.getIcon());
            setLeafIcon(node.getIcon());
        } else {
            System.out.println(node + " - default");
            setClosedIcon(getDefaultClosedIcon());
            setLeafIcon(getDefaultLeafIcon());
            setOpenIcon(getDefaultOpenIcon());
        }
//            }

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

        return this;
    }
}

它清除了所有......

enter image description here

调用setXxxIcon不会影响当前渲染器，但会影响将来的渲染器。那是。如果您在调用setOpenIcon后调用super.getTreeCellRendererComponent，则它不会影响当前渲染器，但会影响super.getTreeCellRendererComponent的下一次调用，因为set方法只是设置值类变量。

其他

Trashgod对依赖于实施及其现在的运作方式做出了有价值的评论。

除了在DefaultTreeCellRenderer#setXxxIcon方法中调用getTreeCellRendererComponent之外，您实际上应该根据传递给它的参数使用所需的图标来调用DefaultTreeCellRenderer#setIcon。

这意味着您可以先调用super.getTreeCellRendererComponent，然后覆盖其后的图标行为。

您还可以获取对Object值的引用并覆盖DefaultTreeCellRenderer#getXxxIcon方法，并根据该值更改这些方法的返回值。我个人而言，因为它改变了渲染器的记录行为
，所以不会勇敢

Answer 3

如果我们需要组件（所以我们需要在第一步调用超级渲染器）重要的是设置所有树图标（打开、关闭、叶子）以使其正常工作。

public java.awt.Component getTreeCellRendererComponent(javax.swing.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);

    DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
    MyTreeNodeWrapper treeNodeWrapper = (MyTreeNodeWrapper) node.getUserObject();
    Icon icon = treeNodeWrapper .getIcon();

    setOpenIcon(icon);
    setClosedIcon(icon);
    setLeafIcon(icon);

    if (!tree.isEnabled()) {
        if (isLeaf) {
            setDisabledIcon(getLeafIcon());
        } else if (expanded) {
            setDisabledIcon(getOpenIcon());
        } else {
            setDisabledIcon(getClosedIcon());
        }
    }
    else {
        if (isLeaf) {
            setIcon(getLeafIcon());
        } else if (expanded) {
            setIcon(getOpenIcon());
        } else {
            setIcon(getClosedIcon());
        }
    }
    
         
return c;

        
}

如果没有，如上所述，我们只需要设置 3 种图标类型：

public java.awt.Component getTreeCellRendererComponent(javax.swing.JTree tree, Object value, boolean selected, boolean expanded, boolean isLeaf, int row, boolean focused) {

    DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
    MyTreeNodeWrapper treeNodeWrapper = (MyTreeNodeWrapper ) node.getUserObject();
    Icon icon = treeNodeWrapper .getIcon();

    setOpenIcon(icon);
    setClosedIcon(icon);
    setLeafIcon(icon);

    
Component c = super.getTreeCellRendererComponent(tree, value, selected, expanded, isLeaf, row, focused);
         
return c;

        
}

JTree：为各个组设置自定义打开/关闭图标

3 个答案: