Question

我想为JTree的特定节点着色（并给出一个图标），而不是像OpenNode，LeafNode等那样的组。我该怎么做呢？

Answer 1

来自Sun的

This tutorial展示了如何设置自己的节点图标以及如何区分树中的叶子和非叶子。

Answer 2

最简单的方法是使用JTree构建DefaultMutableTreeNode模型并设置某些节点的“用户对象”值，然后使用此值确定渲染器遇到该节点时的行为。

首先，我们构造一个简单模型并将其传递给JTree构造函数：

DefaultMutableTreeNode root = new DefaultMutableTreeNode("Hello");
DefaultMutableTreeNode child1 = new DefaultMutableTreeNode("Goodbye");
DefaultMutableTreeNode child2 = new DefaultMutableTreeNode("Bonjour");

root.add(child1);
root.add(child2);

JTree tree = new JTree(root);

现在定义自定义树单元格渲染器：

TreeCellRenderer renderer = new DefaultTreeCellRenderer() {
  public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
    // Defer to superclass to create initial version of JLabel and then modify (below).
    JLabel ret = (JLabel) super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);

    // We know that value is a DefaultMutableTreeNode so this downcast is safe.
    MutableTreeNode node = (MutableTreeNode) value;

    // Inspect user object and change rendering based on this.
    if ("Hello".equals(node.getUserObject())) {
      ret.setIcon(...);
    }

    // Could also inspect whether node is a leaf node, etc.
    return ret;
  }
};

Java树节点着色

2 个答案: