树组件首先要new一个JTree，再加结点，然后添加到 JScrollPane
JTree tree1=new JTree();
//.......添加节点
add(new ScrollPane(tree1)
添加节点
DefaultMutableTreeNode root=new DefaultMutableTreeNode("dongxi")//后面的是备注
DefaultMutableTreeNode root=new DefaultMutableTreeNode(new Good("aa",11));//还可以作为叶子new 对象
添加监视器（由树来添加
addTreeSelectionListener(TreeSelectionListener listener)
TreeSelectionListener接口的方法
public void valueChanged(TreeSelectionEvent e)
在上面的接口方法中，返回树的结点，再返回结点中的对象
DefaultMutableTreeNode node1=(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();//只有树Tree才能用的方法
if(node.isLeaf())//判断是否叶子节点
Obeject a=(Obeject)node.getUserObject()//返回叶子里面的对象
完整的测试代码
public class test{
public static void main(String args[]){
MyWin window1=new MyWin();
window1.setBounds(12,12,400,300);
}
}
class MyWin extends JFrame implements TreeSelectionListener{
JTextField text1;
JButton button1,button2;
JTextArea textArea1,textArea2;
JLabel label1;
JTree tree1;
MyWin(){
init();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void init(){
DefaultMutableTreeNode root=new DefaultMutableTreeNode("Goods");
DefaultMutableTreeNode nodeTV=new DefaultMutableTreeNode("TV");
DefaultMutableTreeNode nodePhone=new DefaultMutableTreeNode("phone");
DefaultMutableTreeNode tv1=new DefaultMutableTreeNode(new Goods("huangTV",11));
DefaultMutableTreeNode tv2=new DefaultMutableTreeNode(new Goods("yuTV",21));
DefaultMutableTreeNode phone1=new DefaultMutableTreeNode(new Goods("ga",31));
DefaultMutableTreeNode phone2=new DefaultMutableTreeNode(new Goods("bing",11));
root.add(nodeTV);
root.add(nodePhone);
nodeTV.add(tv1);
nodeTV.add(tv2);
nodePhone.add(phone1);
nodePhone.add(phone2);
tree1=new JTree(root);
tree1.addTreeSelectionListener(this);
setLayout(new GridLayout(1,2));
add(new JScrollPane(tree1));
textArea2=new JTextArea(15,15);
add(new JScrollPane(textArea2));
}
public void valueChanged(TreeSelectionEvent e){
DefaultMutableTreeNode a=(DefaultMutableTreeNode)tree1.getLastSelectedPathComponent();
if(a.isLeaf()){//是叶子节点？
Goods b=(Goods)a.getUserObject();
textArea2.append(b.name+": "+b.price+"\n");
}
else
textArea2.setText(null);
}
}
class Goods{
String name;
double price;
Goods(String name,double price){
this.name=name;
this.price=price;
}
}
表格组件
Jtable默认的构造方法有7个，这里说常用的3个
JTable()
JTable(int a,int b)//几行几列
JTable(Object data[][],Object columnName[])//data为数据数组，columnName为列名数组
如果表格data[][]是 数字类型，可以用 Double.parseDouble 或者Integer.parseInt(s);
调用repaint来刷新表格
计算成绩代码测试
class MyWin extends JFrame implements ActionListener{
JTable table1;
JButton button1;
Object a[][];
Object name[]={"姓名","英语成绩","数学成绩","总成绩"};
MyWin(){
init();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void init(){
a=new Object[8][4];
for(int i=0;i<8;i++){
for(int j=0;j<4;j++){
if(j!=0)
a[i][j]=0;
else
a[i][j]="姓名";
}
}
button1=new JButton("click");
table1=new JTable(a,name);
Container con1=this.getContentPane();//获得一个容器,不用add
getContentPane().add(new JScrollPane(table1), BorderLayout.CENTER);
con1.add(new JLabel("update the data and click the button"),BorderLayout.NORTH);
con1.add(button1,BorderLayout.SOUTH);
button1.addActionListener(this);
// validate();//验证组件
}
public void actionPerformed(ActionEvent e) {
double sum=0;
boolean boo=true;
for(int i=0;i<8;i++){
sum=0;
for(int j=1;j<3;j++){
try{sum+=Double.parseDouble(a[i][j].toString());
}
catch(Exception ee){
boo=false;
table1.repaint();
}
}
if(boo==true){
a[i][3]=sum+"";//把他改为String
table1.repaint();
}
}
}
}