jtree（选择框）

jtree一般的用法是：

1. 展示电脑中文件的层次结构，如图所示.

具体的代码：

package jtree;

import java.io.File;

import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;

public class ZJtree extends JTree {

    private static final long serialVersionUID = -581164150235777786L;
    private static final String ROOT_NAME = "我的电脑";
    private static final int levelUp = 3;
    
     public ZJtree() {
        this.setModel(new DefaultTreeModel(createRootNode()));
    }

     public  DefaultMutableTreeNode createRootNode(){ 
          DefaultMutableTreeNode treeNode = null;
          DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode(ROOT_NAME); 
          for(int i = 0; i < File.listRoots().length ; i++){ 
              if(File.listRoots()[i].isDirectory()){ 
                  String rootPath = File.listRoots()[i].getPath(); 
                  treeNode  = creatDefaultMutableTreeNode(rootPath,0); 
                  rootNode.add(treeNode); 
                  treeNode = null;
              } 
          } 

            return rootNode; 
        }

    private DefaultMutableTreeNode creatDefaultMutableTreeNode(String nodePath,int level) {
        DefaultMutableTreeNode node = new DefaultMutableTreeNode(nodePath);
        DefaultMutableTreeNode treeNode = null;
        level = level+1;
        File file = new File(nodePath);
        if(file.isDirectory() && file.listFiles() != null){
             for(int i = 0; i < file.listFiles().length && level < levelUp; i++){ 
                  if(file.listFiles()[i].isDirectory()){ 
                      String rootPath = file.listFiles()[i].getPath();
                      treeNode  = creatDefaultMutableTreeNode(rootPath,level); 
                      node.add(treeNode); 
                      treeNode = null; 
                  } 
              }
        }
         
        return node;
    }

}

说明：限制层次的原因是因为电脑中文件过多，一直加载会比较的慢，以后我们会在处理这个问题。

看到上面的那个界面的第一个反应，就是好丑啊，我们慢慢的优化。在树节点的选择上面，增加combox，一步一步的来。

首先我们新建一个扩展自Jtree的自定义类：

public class ZTreeCheckBox extends JTree {

    private static final long serialVersionUID = -581164150235777786L;
    private static final String ROOT_NAME = "p";
    private static final int levelUp = 3;
    
     public ZTreeCheckBox() {
        this.setModel(new DefaultTreeModel(createRootNode()));
        this.setCellRenderer(new ChectBoxTreeCellRender());
        this.addCheckSelectListender();
    }

     private void addCheckSelectListender() {
         this.addMouseListener(new CheckBoxTreeNodeListender(this));
    }

    public  CheckBoxTreeNode createRootNode(){ 
         CheckBoxTreeNode treeNode = null;
         CheckBoxTreeNode rootNode = new CheckBoxTreeNode(ROOT_NAME); 
          for(int i = 0; i < File.listRoots().length ; i++){ 
              if(File.listRoots()[i].isDirectory()){ 
                  String rootPath = File.listRoots()[i].getPath(); 
                  treeNode  = creatDefaultMutableTreeNode(rootPath,0); 
                  rootNode.add(treeNode); 
                  treeNode = null;
              } 
          } 

            return rootNode; 
        }

    private CheckBoxTreeNode creatDefaultMutableTreeNode(String nodePath,int level) {
        CheckBoxTreeNode node = new CheckBoxTreeNode(nodePath);
        CheckBoxTreeNode treeNode = null;
        level = level+1;
        File file = new File(nodePath);
        if(file.isDirectory() && file.listFiles() != null){
             for(int i = 0; i < file.listFiles().length && level < levelUp; i++){ 
                  if(file.listFiles()[i].isDirectory()){ 
                      String rootPath = file.listFiles()[i].getPath();
                      treeNode  = creatDefaultMutableTreeNode(rootPath,level); 
                      node.add(treeNode); 
                      treeNode = null; 
                  } 
              }
        }
         
        return node;
    }
}

tree 的数据的组织形式，还和原来一样，但是我们需要tree的节点的形式是Combox形式的，最起码前面要是一个可选的样子，所以我们自定义一个TreeCellRenderer，我们在显示的时候可以是一个Jpanel，其中包含一个combox，一个Jlabel代码如下：

public class ChectBoxTreeCellRender extends JPanel implements
        TreeCellRenderer {

    private static final long serialVersionUID = 4676667399191240255L;

    
    protected JCheckBox check;
    protected CheckBoxTreeLabel label;
//    protected JLabel label;
    public ChectBoxTreeCellRender() {
        setLayout(null);
        add(check = new JCheckBox());
        add(label = new CheckBoxTreeLabel());
//        add(label = new JLabel());
        check.setBackground(UIManager.getColor("Tree.textBackground"));
        label.setForeground(UIManager.getColor("Tree.textForeground"));
        this.setPreferredSize(new Dimension(100, 20));
    }
    
    
    /* (non-Javadoc)
     * @see javax.swing.tree.TreeCellRenderer#getTreeCellRendererComponent(javax.swing.JTree, java.lang.Object, boolean, boolean, boolean, int, boolean)
     */
    @Override
    public Component getTreeCellRendererComponent(JTree tree, Object value,
            boolean selected, boolean expanded, boolean leaf, int row,
            boolean hasFocus) {
        String stringValue = tree.convertValueToText(value, selected, expanded,
                leaf, row, hasFocus);
        setEnabled(tree.isEnabled());
        check.setSelected(((CheckBoxTreeNode) value).isSelect());
        label.setFont(tree.getFont());
        label.setText(stringValue);
        label.setSelected(selected);
        label.setFocus(hasFocus);
        if (leaf)
            label.setIcon(UIManager.getIcon("Tree.leafIcon"));
        else if (expanded)
            label.setIcon(UIManager.getIcon("Tree.openIcon"));
        else
            label.setIcon(UIManager.getIcon("Tree.closedIcon"));

        return this;
    }
    @Override
    public void doLayout() {
        Dimension dCheck = check.getPreferredSize();
        Dimension dLabel = label.getPreferredSize();
        int yCheck = 0;
        int yLabel = 0;
        if (dCheck.height < dLabel.height)
            yCheck = (dLabel.height - dCheck.height) / 2;
        else
            yLabel = (dCheck.height - dLabel.height) / 2;
        check.setLocation(0, yCheck);
        check.setBounds(0, yCheck, dCheck.width, dCheck.height);
        label.setLocation(dCheck.width, yLabel);
        label.setBounds(dCheck.width, yLabel, dLabel.width, dLabel.height);
    }

    @Override
    public void setBackground(Color color) {
        if (color instanceof ColorUIResource)
            color = null;
        super.setBackground(color);
    }
}

关于选中了节点以后，label是否出现阴影表示选择，在这里不是重点，这个扩展CheckBoxTreeLabel，会放在git上，现在我们关注的是Jlabel和Combox的结合而成的JPanel。

现在我们还缺少一个选择以后，Combox能够显示选中，所以我们还需要增加增加一个节点选择的监听：

public class CheckBoxTreeNodeListender extends MouseAdapter {

    private ZTreeCheckBox zTreeCheckBox = null;

    public CheckBoxTreeNodeListender(ZTreeCheckBox zTreeCheckBox) {

        this.zTreeCheckBox = zTreeCheckBox;
    }

    // 被选中事件
    @Override
    public void mousePressed(MouseEvent event) {
        
        if(event.getSource() instanceof ZTreeCheckBox){
            Point p = event.getPoint();
            int row = zTreeCheckBox.getRowForLocation(p.x, p.y);
            TreePath path = zTreeCheckBox.getPathForRow(row);
            if (path != null) {
                CheckBoxTreeNode node = (CheckBoxTreeNode) path
                        .getLastPathComponent();
                if (node != null) {
                    boolean isSelected = !node.isSelect();
                    node.setSelected(isSelected);
                    ((DefaultTreeModel) zTreeCheckBox.getModel()).nodeStructureChanged(node);
                }
            }
        }
        
//        else{
//            String comm = ((JButton)event.getSource()).getActionCommand();
//        }
//        
    }

}

最后我们得到是这个样子的：

左边的按钮，表示的选择的操作：

① 全部的选中

② 全部的不选中

③ 选择一个子树

④ 去除某一个子树

一种实现的思路，是在选择的事件分为四类，然后实现对应的逻辑，也就是对每一个节点的选择做出操作。在CheckBoxTreeNodeListender 的监听响应中添加：

// 被选中事件
    @Override
    public void mousePressed(MouseEvent event) {
        Point p = event.getPoint();
        int row = zTreeCheckBox.getRowForLocation(p.x, p.y);
        TreePath path = zTreeCheckBox.getPathForRow(row);
        
        if(event.getSource() instanceof ZTreeCheckBox){
            if (path != null) {
                CheckBoxTreeNode node = (CheckBoxTreeNode) path
                        .getLastPathComponent();
                if (node != null) {
                    boolean isSelected = !node.isSelect();
                    node.setSelected(isSelected);
                    ((DefaultTreeModel) zTreeCheckBox.getModel()).nodeStructureChanged(node);
                }
            }
        }
        
        else{
            String comm = ((JButton)event.getSource()).getActionCommand();
            if("SelectAll".equals(comm)){
                CheckBoxTreeNode node = (CheckBoxTreeNode) path.getLastPathComponent();
                selectAllNode(node,true);
                ((DefaultTreeModel) zTreeCheckBox.getModel()).nodeStructureChanged(node);
            }else if("DeselectAll".equals(comm)){
                CheckBoxTreeNode node = (CheckBoxTreeNode) path.getLastPathComponent();
                selectAllNode(node,false);
                ((DefaultTreeModel) zTreeCheckBox.getModel()).nodeStructureChanged(node);
            }
        }
//        
    }

    private void selectAllNode(CheckBoxTreeNode node,boolean select) {
        if (node != null) {
            node.setSelected(select);
            if(node.getChildCount() > 0 ){
                for (int i = 0; i < node.getChildCount(); i++) {
                    CheckBoxTreeNode child = (CheckBoxTreeNode) node.getChildAt(i);
                    selectAllNode(child,select);
                }
            }
            
        }
        
    }

类似的实现，即可满足条件，封装性不是很好，有时间在进行重构，抽成一个借口，和对应的实现。

下一篇我们的实现成这样：

改变树节点的图片，变得好看一点。