jTree 用法

最新推荐文章于 2022-05-12 16:25:51 发布

paulfzm

最新推荐文章于 2022-05-12 16:25:51 发布

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分类专栏： Java 文章标签： Swing QQ UP

本文链接：https://blog.youkuaiyun.com/paulfzm/article/details/83841404

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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);

setBounds(int x, int y, int width, int height)方法的应用

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。

思考

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。