jTree 用法
import java.awt.Dimension;
import java.awt.Color;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.BoxLayout;
import javax.swing.tree.TreePath;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
/*
JTree的构造函数:
JTree()
JTree(Hashtable value)
JTree(Object[] value)//只有这个构造函数可以创建多个根结点
JTree(TreeModel newModel)
JTree(TreeNode root)
JTree(TreeNode root, boolean asksAllowsChildren)
JTree(Vector value)
*/
public class JTreeDemo
{
public static void main (String[] args)
{
//构造函数：JTree()
JTree example1 = new JTree();
//构造函数：JTree(Object[] value)
Object[] letters= {"a", "b", "c", "d", "e"};
JTree example2 = new JTree (letters);
//构造函数：JTree(TreeNode root)(TreeNode空)
//用空结点创建树
DefaultMutableTreeNode node1 = new DefaultMutableTreeNode();//定义树结点
JTree example3 = new JTree (node1);//用此树结点做参数调用 JTree的构造函数创建含有一个根结点的树
//构造函数：JTree(TreeNode root)(同上,只是TreeNode非空)
//用一个根结点创建树
DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Color");
JTree example4 = new JTree (node2);//结点不可以颜色,默认为白面黑字
example4.setBackground (Color.lightGray);
//构造函数：JTree(TreeNode root, boolean asksAllowsChildren)(同上,只是TreeNode又有不同)
//使用DefaultMutableTreeNode类先用一个根结点创建树，设置为可添加孩子结点,再添加孩子结点
DefaultMutableTreeNode color = new DefaultMutableTreeNode("Color", true);
DefaultMutableTreeNode gray = new DefaultMutableTreeNode ("Gray");
color.add (gray);
color.add (new DefaultMutableTreeNode ("Red"));
gray.add (new DefaultMutableTreeNode ("Lightgray"));
gray.add (new DefaultMutableTreeNode ("Darkgray"));
color.add (new DefaultMutableTreeNode ("Green"));
JTree example5 = new JTree (color);
//构造函数：JTree(TreeNode root)(同上,只是TreeNode非空)
//通过逐个添加结点创建树
DefaultMutableTreeNode biology = new DefaultMutableTreeNode ("Biology");
DefaultMutableTreeNode animal = new DefaultMutableTreeNode ("Animal");
DefaultMutableTreeNode mammal = new DefaultMutableTreeNode ("Mammal");
DefaultMutableTreeNode horse = new DefaultMutableTreeNode ("Horse");
mammal.add (horse);
animal.add (mammal);
biology.add (animal);
JTree example6 = new JTree (biology);
horse.isLeaf();
horse.isRoot();
//构造函数:JTree(TreeModel newModel)
//用DefaultMutableTreeNodel类定义一个结点再用这个结点做参数定义一个用DefaultTreeMode
//创建一个树的模型,再用JTree的构造函数创建一个树
DefaultMutableTreeNode root = new DefaultMutableTreeNode ("Root1");
DefaultMutableTreeNode child1 = new DefaultMutableTreeNode ("Child1");
DefaultMutableTreeNode child11 = new DefaultMutableTreeNode ("Child11");
DefaultMutableTreeNode child111 = new DefaultMutableTreeNode ("Child111");
root.add (child1); child1.add (child11); child11.add (child111);
DefaultTreeModel model = new DefaultTreeModel (root);
JTree example7 = new JTree (model);
JPanel panel = new JPanel();
panel.setLayout (new BoxLayout (panel, BoxLayout.X_AXIS));
panel.setPreferredSize (new Dimension (700, 400));
panel.add (new JScrollPane (example1));//JTree必须放在JScrollPane上
panel.add (new JScrollPane (example2));
panel.add (new JScrollPane (example3));
panel.add (new JScrollPane (example4));
panel.add (new JScrollPane (example5));
panel.add (new JScrollPane (example6));
panel.add (new JScrollPane (example7));
JFrame frame = new JFrame ("JTreeDemo");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.setContentPane (panel);
frame.pack();
frame.show();
}
}在实际开发过程中会经常使用JTree组件，平时会遇到这样或那样的问题，在此将偶得一点经验写下来，与大家共享，希望对大家有所帮助。
private JTree jtNetDevice;//数组件申明
private JScrollPane jspTree;//滚动面板申明
1、初始化
DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("root");
jtNetDevice = new JTree(rootNode);
jtNetDevice.setAutoscrolls(true);
getTreeSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);//设置单选模式
jspTree = new JScrollPane();
jspTree.getViewport().add(jtNetDevice, null);
2、三个经常使用的取值函数
private DefaultTreeModel getTreeModel(){
return (DefaultTreeModel)jtNetDevice.getModel();
}
private DefaultMutableTreeNode getRootNode(){
return (DefaultMutableTreeNode)getTreeModel().getRoot();
}
private TreeSelectionModel getTreeSelectionModel(){
return jtNetDevice.getSelectionModel();
}
3、根据node得到path：
TreePath visiblePath = new TreePath(getTreeModel().getPathToRoot(node));
4、根据Path展开到该节点
jtNetDevice.makeVisible(visiblePath);
5、根据path设定该节点选定
jtNetDevice.setSelectionPath(visiblePath);
6、选中节点的方法
首先，根据节点得到树路径，其中chosen为需要选中的节点
TreePath visiblePath = new TreePath( ( (DefaultTreeModel) jtNetDevice.getModel()).
getPathToRoot(chosen));
然后根据Path选中该节点
jtNetDevice.setSelectionPath(visiblePath);
7、滚动到可见位置
jtNetDevice.scrollPathToVisible(visiblePath);
8、给JTree添加右键弹出菜单
void jtNetDevice_mouseReleased(MouseEvent e) {
if (e.isPopupTrigger()) {
jPopupMenu1.show(e.getComponent(), e.getX(), e.getY());//弹出右键菜单
}
}
9、关于JTree的展开
// If expand is true, expands all nodes in the tree.
// Otherwise, collapses all nodes in the tree.
public void expandAll(JTree tree, boolean expand) {
TreeNode root = (TreeNode)tree.getModel().getRoot();
// Traverse tree from root
expandAll(tree, new TreePath(root), expand);
}
private void expandAll(JTree tree, TreePath parent, boolean expand) {
// Traverse children
TreeNode node = (TreeNode)parent.getLastPathComponent();
if (node.getChildCount() >= 0) {
for (Enumeration e=node.children(); e.hasMoreElements(); ) {
TreeNode n = (TreeNode)e.nextElement();
TreePath path = parent.pathByAddingChild(n);
expandAll(tree, path, expand);
}
}
// Expansion or collapse must be done bottom-up
if (expand) {
tree.expandPath(parent);
} else {
tree.collapsePath(parent);
}
}
10、如何遍历JTree
// 创建树
JTree tree = new JTree();
// 添加树节点......
// 遍历所有节点
visitAllNodes(tree);
// 仅遍历展开的节点
visitAllExpandedNodes(tree);
// Traverse all nodes in tree
public void visitAllNodes(JTree tree) {
TreeNode root = (TreeNode)tree.getModel().getRoot();
visitAllNodes(root);
}
public void visitAllNodes(TreeNode node) {
// node is visited exactly once
process(node);
if (node.getChildCount() >= 0) {
for (Enumeration e=node.children(); e.hasMoreElements(); ) {
TreeNode n = (TreeNode)e.nextElement();
visitAllNodes(n);
}
}
}
// Traverse all expanded nodes in tree
public void visitAllExpandedNodes(JTree tree) {
TreeNode root = (TreeNode)tree.getModel().getRoot();
visitAllExpandedNodes(tree, new TreePath(root));
}
public void visitAllExpandedNodes(JTree tree, TreePath parent) {
// Return if node is not expanded
if (!tree.isVisible(parent)) {
return;
}
// node is visible and is visited exactly once
TreeNode node = (TreeNode)parent.getLastPathComponent();
process(node);
// Visit all children
if (node.getChildCount() >= 0) {
for (Enumeration e=node.children(); e.hasMoreElements(); ) {
TreeNode n = (TreeNode)e.nextElement();
TreePath path = parent.pathByAddingChild(n);
visitAllExpandedNodes(tree, path);
}
}
}
jTree
已经有近一个半月没有写总结了，蛮惭愧的，这说明我的毅力不足。一旦把精力放在专业课上，数天不敲编码，整个人就松懈下来了。前几天，参阅QQ界面相关资料时，看到了这样一句话：如今我来了，你们看到的也将不同.....而我们呢？我们来到了蓝杰，可是我们究竟改变了多少了？我想这和我们投入的时间和精力是成正比的。现在的我还很烂，不过我也会一步步让你们看到我的改变。。。。
步入正题！
这几天一直在尝试做QQ界面，查阅资料下，掌握了对JTree添加图片的方法，以及Swing组件的setBounds(int x, int y, int width, int height)方法的应用
JTree添加图片
1.首先定义根节点和叶节点
DefaultMutableTreeNode root = new DefaultMutableTreeNode("根节点"); DefaultMutableTreeNode leafNode1 = new DefaultMutableTreeNode("叶节点1");
DefaultMutableTreeNode leafNode2 = new DefaultMutableTreeNode("叶节点2");
root.add(leafNode1);
root.add(leafNode2);
2.设置树的显示风格
UIManager.getDefaults().put("Tree.lineTypeDashed", true);// 设置连接线为虚线
UIManager.getDefaults().put("Tree.lineTypeDashed",false); //设置连接线为直线
JTree tree = new JTree(root);//建树
tree.putClientProperty("JTree.lineStyle","None");//去掉连接线 tree.putClientProperty("JTree.lineStyle","Horizontal");//将树设为水平分隔风格 tree.putClientProperty("JTree.lineStyle","Angled");//默认
3.给树上节点添加图片
首先要获得树的DefaultTreeCellRenderer
DefaultTreeCellRenderer renderer = (DefaultTreeCellRenderer) tree.getCellRenderer();
Icon rootIcon = new ImageIcon("rootIcon路径"); Icon leafIcon = new ImageIcon("leafIcon路径");
添加图片
rend.setLeafIcon(leafIcon);//叶节点图片 rend.setOpenIcon(rootIcon);//树打开时显示的图片 rend.setClosedIcon(collIcon);//树关闭时显示的图片
若要隐藏根节点
tree.setRootVisible(false);
很早以前就看到了这个方法，其说明：（x,y）为组件显示的坐标，（width,height）为组件的宽和高
但无论我怎么设置都没有用，知道前天看到了一个具体实例才豁然开朗,只需要加上一行代码：
this.setLayout(null);
郁闷，很多时候困扰我的都是一行代码的事。
初学JAVA不过2个多月，我们对API类的运用还处于低级水平。我想，同小组的很多人都没有用过API类库，上面有详细的注解和实例，我也是前天才下了一个。API类库是一个很好的工具。
其次，我们添加组件调用的都是API库内现成的类，很多时候都达不到我们想要的效果，如果我们写一个类继承某个组件，在其内写方法进行设置，可能就方便很多。比如给JButton添加图标，写一个类MyJButton extends JButton ，在其构造器内传入图标。。。对JTree添图标也可以采用相同的做法。。。
这只是我的一些小想法，还没有真的用过，只是一种思路罢了。