为Jtree中的每个节点设置图标

Question

我想为 JTree 组件中的每个节点设置不同的图标。我使用

while

循环从数据库加载每个节点。我将每个图标设置为根、叶或父级。我将它们设置如下：

我所有的声明都是全球性的：

private ResultSet myResultSet;
protected DefaultTreeModel treeModel;
private DefaultMutableTreeNode rootNode,childNode,parent1,parent2;

这就是我设置节点的方式：

myResultSet=rtnNodes(); /*Method that returns a RS with my nodes*/
while(myResultSet.next()){
  switch(myResultSet.getInt(1)){  /*The first column is the type of node: root, parent, leaf...*/
    case 0: treeModel = new DefaultTreeModel((rootNode=new DefaultMutableTreeNode(myResultSet.getString(2)))); break;  /*root node*/
    case 1: case 4: parent1 = parent2 = makeNode(rootNode); break;  /*parent node*/
    case 2: makeNode(parent2); break;  /*leaf node*/
    case 3: parent2 = makeNode(parent1); break;  /*sub patern node*/
  } /*makeNode is the method where I create the nodes*/
}

makeNode

方法是这样的：

public DefaultMutableTreeNode makeNode(DefaultMutableTreeNode parent){
  //The second column in the RS is the name of the node
  treeModel.insertNodeInto((childNode=new DefaultMutableTreeNode(myResultSet.getString(2))),parent,parent.getChildCount());
  return childNode;
}

用我的节点填充

treemodel

后，我将模型设置为我的 JTree：

myJTree.setModel(treeModel);
myJTree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

但是当我尝试设置图标时问题就来了。我创建了一个名为 MyTreeRenderer 的子类，并使用它：

myJTree.setCellRenderer(new MyTreeRenderer());

但是它没有按照我想要的方式设置图标，子类是：

private ImageIcon root,parent,leaf;

public MyTreeRenderer() {
   root=setIcons(2);  /*setIcons is a method that I dont publish in this post, that helps me to set the path of the icons*/
   parent=setIcons(3);
   leaf=setIcons(4);
}

@Override
public Component getTreeCellRendererComponent(JTree tree,Object value,boolean selected,boolean expanded,boolean leaf,int row,boolean hasFocus){               
   super.getTreeCellRendererComponent(tree,value,selected,expanded,leaf,row,hasFocus);
   DefaultMutableTreeNode nodo = (DefaultMutableTreeNode)value;
   TreeNode t = nodo.getParent();
   if(t!=null){
      setIcon(root);
   }
   return this;
}

如何为每个节点设置图标而不使用他的名字？子类的代码，按原样，将所有节点设置为相同的图标，每次我在jtree中选择一个节点时，

getTreeCellRendererComponent

都会运行，我不希望这样。

Answer 1

您可以更改

JTree

节点图标的默认 UI 值，无需任何自定义渲染器：

URL resource = logaff.class.getResource(IMAGE);
Icon icon = new ImageIcon(resource);

UIManager.put("Tree.closedIcon", icon);
UIManager.put("Tree.openIcon", icon);
UIManager.put("Tree.leafIcon", icon);

或者使用类似下一个的东西：

@Override
public Component getTreeCellRendererComponent(JTree tree,
    Object value, boolean selected, boolean expanded,
    boolean leaf, int row, boolean hasFocus) {
        super.getTreeCellRendererComponent(tree, value, selected,expanded, leaf, row, hasFocus);
        DefaultMutableTreeNode nodo = (DefaultMutableTreeNode) value;
        if (tree.getModel().getRoot().equals(nodo)) {
            setIcon(root);
        } else if (nodo.getChildCount() > 0) {
            setIcon(parent);
        } else {
            setIcon(leaf);
        }
        return this;
}

另请阅读渲染机制。

Answer 2

您可以使用它，更短的方式。 “tree”是我的 JTree 组件。

DefaultTreeCellRenderer renderer = (DefaultTreeCellRenderer) tree.getCellRenderer();
Icon closedIcon = new ImageIcon("closed.png");
Icon openIcon = new ImageIcon("open.png");
Icon leafIcon = new ImageIcon("leaf.png");
renderer.setClosedIcon(closedIcon);
renderer.setOpenIcon(openIcon);
renderer.setLeafIcon(leafIcon);