树组 输出问题 ，求大侠帮助啊
。。。。数组 名字和得分输不出来，不知道哪里错了 ，请求指点import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import javax.swing.event.*;
public class Tree {
public static void main(String args[]){
new TreeWin();
}
}
class Student{
String name;
double score;
//doube MajorSpeciaty;
Student(String name,double score){
this.name=name;
this.score=score;
}
public String toString(){
return name;
}
abstract class TreeWin extends JFrame implements TreeSelectionListener{
JTree tree;
JTextArea showText;
TreeWin(){
DefaultMutableTreeNode root=new DefaultMutableTreeNode("华北科技学院");
DefaultMutableTreeNode node=new DefaultMutableTreeNode("信息与计算科学");
DefaultMutableTreeNode nodeson1=new DefaultMutableTreeNode(new Student("三",98));
DefaultMutableTreeNode nodeson2=new DefaultMutableTreeNode(new Student("四",88));
DefaultMutableTreeNode nodeson3=new DefaultMutableTreeNode(new Student("五",78));
root.add(node);
node.add(nodeson1);
node.add(nodeson2);
node.add(nodeson3);
tree=new JTree(root);
tree.addTreeSelectionListener(this);
showText=new JTextArea();
setLayout(new GridLayout(1,2));
add(new JScrollPane(tree));
add(new JScrollPane(showText));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setBounds(350,400,300,300);
validate();
}
public void valueChaged(TreeSelectionEvent e){
DefaultMutableTreeNode node=(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
if(node.isLeaf()){
Student s=(Student)node.getUserObject();
showText.append(s.name+","+s.score+"."+"\n");
}
else {
showText.setText(null);
}
}
}
}
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我就不知道你的程序是怎么跑起来的。。。。。。。。。。。。
new 一个抽象的类，肯定是要报错的..
我刚刚修改了一下，
package gfgfg;
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import javax.swing.event.*;
class Student{
String name;
double score;
//doube MajorSpeciaty;
Student(String name,double score){
this.name=name;
this.score=score;
}
public String toString(){
return name;
}
}
public class TreeWin extends JFrame implements TreeSelectionListener{
JTree tree;
JTextArea showText;
TreeWin(){
DefaultMutableTreeNode root=new DefaultMutableTreeNode("华北科技学院");
DefaultMutableTreeNode node=new DefaultMutableTreeNode("信息与计算科学");
DefaultMutableTreeNode nodeson1=new DefaultMutableTreeNode(new Student("三",98));
DefaultMutableTreeNode nodeson2=new DefaultMutableTreeNode(new Student("四",88));
DefaultMutableTreeNode nodeson3=new DefaultMutableTreeNode(new Student("五",78));
root.add(node);
node.add(nodeson1);
node.add(nodeson2);
node.add(nodeson3);
tree=new JTree(root);
tree.addTreeSelectionListener(this);
showText=new JTextArea();
setLayout(new GridLayout(1,2));
add(new JScrollPane(tree));
add(new JScrollPane(showText));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setBounds(350,400,300,300);
validate();
}
@Override
public void valueChanged(TreeSelectionEvent e) {
DefaultMutableTreeNode node=(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
if(node.isLeaf()){
Student s=(Student)node.getUserObject();
showText.append(s.name+","+s.score+"."+"\n");
}
else {
showText.setText(null);
}
}
public static void main(String[]args){
new TreeWin();
}
}
----------------解决方案--------------------------------------------------------
谢谢你 ，终与可以执行了，我头都想爆了了 呵呵
----------------解决方案--------------------------------------------------------
谢谢你！要不是你我不知道还有多久才能弄出来
我还有些不明白 ：你再帮我看一下好不？ 在下感激不进
刚开始老报这个错误：
E:JAVAtry>javac TreeWin.java
TreeWin.java:19: TreeWin 不是抽象的，并且未覆盖 javax.swing.event.TreeSelectionL
istener 中的抽象方法 valueChanged(javax.swing.event.TreeSelectionEvent)
public class TreeWin extends JFrame implements TreeSelectionListener{
后来无赖我就在class TreeWin 前加了个抽象类关键字。
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import javax.swing.event.*;
class Student{
String name;
double score;
Student(String name,double score){
this.name=name;
this.score=score;
}
public String toString(){
return name;
}
}
public class TreeWin extends JFrame implements TreeSelectionListener{
JTree tree=null;
JTextArea showText;
TreeWin(){
DefaultMutableTreeNode root=new DefaultMutableTreeNode("华北科技学院");
DefaultMutableTreeNode node=new DefaultMutableTreeNode("信息与计算科学");
DefaultMutableTreeNode nodeson1=new DefaultMutableTreeNode(new Student("三",98));
DefaultMutableTreeNode nodeson2=new DefaultMutableTreeNode(new Student("四",88));
DefaultMutableTreeNode nodeson3=new DefaultMutableTreeNode(new Student("五",78));
root.add(node);
node.add(nodeson1);
node.add(nodeson2);
node.add(nodeson3);
tree=new JTree(root);
tree.addTreeSelectionListener(this);
showText=new JTextArea();
setLayout(new GridLayout(1,2));
add(new JScrollPane(tree));
add(new JScrollPane(showText));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setBounds(350,400,300,300);
validate();
}
public void valueChaged(TreeSelectionEvent e){
DefaultMutableTreeNode node=(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
if(node.isLeaf()){
Student s=(Student)node.getUserObject();
showText.append(s.name+","+s.score+"."+"n");
}
else {
showText.setText(null);
}
}
public static void main(String args[]){
new TreeWin();
}
}
----------------解决方案--------------------------------------------------------
你用一个类A继承另一个类B，A必须实现B中的抽象方法。。。不然的话，A也必须为抽象的.......所以你会报那个错。
你在main方法中，必须new一个非抽象类，new一个抽象类是没有意义的。。。
一般情况就是new一个抽象类的子类。。。
----------------解决方案--------------------------------------------------------
好像明白一些了
谢谢你了！
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