我这个程序执行没问题 我就是想实现对下拉框内容的选择 如果选择了test1 让f显示我要显示的内容;可是现在问题是 内容显示不出来 只显示行数 也不能想选择test1 test2 test3其中之一 用什么方法呢 着急!!!!!谢谢import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JPopupMenu;
import java.io.*;public class Exam extends JFrame{
JFrame jframe=new JFrame("考试系统");
JButton a,b,c,d;
JLabel s,t,p,s1,s2;
JTextArea f,text;
Box b1,b2,b3,b4,b5;
Choice th = new Choice();
Checkbox x,y,pt,tf;
public Exam(){
//复选框
x=new Checkbox("A");
y=new Checkbox("B");
pt=new Checkbox("C");
tf=new Checkbox("D");
//下拉框
th.add("Test1");
th.add("Test2");
th.add("Test3");
s=new JLabel("单机考试系统");
t=new JLabel("试题内容");
p=new JLabel("选择试题文件");
s1=new JLabel("剩余时间");
s2=new JLabel("时间:");
setSize(50,60);
setVisible(true);
Container com=getContentPane();
b1=Box.createHorizontalBox();
b2=Box.createHorizontalBox();
b3=Box.createVerticalBox();
b4=Box.createVerticalBox();
b5=Box.createVerticalBox();
//按钮
a=new JButton("提交该题答案");
b=new JButton("提取下一题目");
c=new JButton("考试得分");
d=new JButton("暂停计时");
//文本框
f=new JTextArea(20,30);
text=new JTextArea(5,6);
com.setLayout(new BorderLayout(2,2));
b3.add(p);
b3.add(th);
b3.add(text);
b3.add(c);
b5.add(s1);
b5.add(s2);
b5.add(d);
b3.add(b5,BorderLayout.SOUTH);
com.add(b3,BorderLayout.WEST);
b1.add(x);
b1.add(y);
b1.add(pt);
b1.add(tf);
b1.add(a); b1.add(b);
b4.add(t);
b4.add(f);
b4.add(b1);
com.add(b4,BorderLayout.CENTER);
com.add(s,BorderLayout.NORTH);
com.validate();
th.addItemListener(new MyExam());
}
class MyExam implements ItemListener{
public void itemStateChanged(ItemEvent ie){
if(ie.getStateChange()==ItemEvent.SELECTED){
//String test1="selected";
// String test2="selected";
//String test3="selected;"
}
String record =null;
int recCount = 0;
try{
FileReader fr =new FileReader("C:/Documents and Settings/Administrator/桌面/student2/考试系统/Test1.txt");
BufferedReader br = new BufferedReader(fr);
record =new String();
while((record = br.readLine())!=null){
recCount++;
f.setText("Line"+recCount+":"+record);
}
br.close();
fr.close();
}
catch(IOException e){
e.printStackTrace();
}
}
}
public static void main(String []args){
Exam pd=new Exam();
pd.pack();
}
}
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JPopupMenu;
import java.io.*;public class Exam extends JFrame{
JFrame jframe=new JFrame("考试系统");
JButton a,b,c,d;
JLabel s,t,p,s1,s2;
JTextArea f,text;
Box b1,b2,b3,b4,b5;
Choice th = new Choice();
Checkbox x,y,pt,tf;
public Exam(){
//复选框
x=new Checkbox("A");
y=new Checkbox("B");
pt=new Checkbox("C");
tf=new Checkbox("D");
//下拉框
th.add("Test1");
th.add("Test2");
th.add("Test3");
s=new JLabel("单机考试系统");
t=new JLabel("试题内容");
p=new JLabel("选择试题文件");
s1=new JLabel("剩余时间");
s2=new JLabel("时间:");
setSize(50,60);
setVisible(true);
Container com=getContentPane();
b1=Box.createHorizontalBox();
b2=Box.createHorizontalBox();
b3=Box.createVerticalBox();
b4=Box.createVerticalBox();
b5=Box.createVerticalBox();
//按钮
a=new JButton("提交该题答案");
b=new JButton("提取下一题目");
c=new JButton("考试得分");
d=new JButton("暂停计时");
//文本框
f=new JTextArea(20,30);
text=new JTextArea(5,6);
com.setLayout(new BorderLayout(2,2));
b3.add(p);
b3.add(th);
b3.add(text);
b3.add(c);
b5.add(s1);
b5.add(s2);
b5.add(d);
b3.add(b5,BorderLayout.SOUTH);
com.add(b3,BorderLayout.WEST);
b1.add(x);
b1.add(y);
b1.add(pt);
b1.add(tf);
b1.add(a); b1.add(b);
b4.add(t);
b4.add(f);
b4.add(b1);
com.add(b4,BorderLayout.CENTER);
com.add(s,BorderLayout.NORTH);
com.validate();
th.addItemListener(new MyExam());
}
class MyExam implements ItemListener{
public void itemStateChanged(ItemEvent ie){
if(ie.getStateChange()==ItemEvent.SELECTED){
//String test1="selected";
// String test2="selected";
//String test3="selected;"
}
String record =null;
int recCount = 0;
try{
FileReader fr =new FileReader("C:/Documents and Settings/Administrator/桌面/student2/考试系统/Test1.txt");
BufferedReader br = new BufferedReader(fr);
record =new String();
while((record = br.readLine())!=null){
recCount++;
f.setText("Line"+recCount+":"+record);
}
br.close();
fr.close();
}
catch(IOException e){
e.printStackTrace();
}
}
}
public static void main(String []args){
Exam pd=new Exam();
pd.pack();
}
}
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JPopupMenu;
import java.io.*;public class Exam extends JFrame{
JFrame jframe=new JFrame("考试系统");
JButton a,b,c,d;
JLabel s,t,p,s1,s2;
JTextArea f,text;
Box b1,b2,b3,b4,b5;
Choice th = new Choice();
Checkbox x,y,pt,tf;
public Exam(){
//复选框
x=new Checkbox("A");
y=new Checkbox("B");
pt=new Checkbox("C");
tf=new Checkbox("D");
//下拉框
th.add("Test1");
th.add("Test2");
th.add("Test3");
s=new JLabel("单机考试系统");
t=new JLabel("试题内容");
p=new JLabel("选择试题文件");
s1=new JLabel("剩余时间");
s2=new JLabel("时间:");
setSize(50,60);
setVisible(true);
Container com=getContentPane();
b1=Box.createHorizontalBox();
b2=Box.createHorizontalBox();
b3=Box.createVerticalBox();
b4=Box.createVerticalBox();
b5=Box.createVerticalBox();
//按钮
a=new JButton("提交该题答案");
b=new JButton("提取下一题目");
c=new JButton("考试得分");
d=new JButton("暂停计时");
//文本框
f=new JTextArea(20,30);
text=new JTextArea(5,6);
com.setLayout(new BorderLayout(2,2));
b3.add(p);
b3.add(th);
b3.add(text);
b3.add(c);
b5.add(s1);
b5.add(s2);
b5.add(d);
b3.add(b5,BorderLayout.SOUTH);
com.add(b3,BorderLayout.WEST);
b1.add(x);
b1.add(y);
b1.add(pt);
b1.add(tf);
b1.add(a); b1.add(b);
b4.add(t);
b4.add(f);
b4.add(b1);
com.add(b4,BorderLayout.CENTER);
com.add(s,BorderLayout.NORTH);
com.validate();
th.addItemListener(new MyExam());
}
class MyExam implements ItemListener{
public void itemStateChanged(ItemEvent ie){
if(ie.getStateChange()==ItemEvent.SELECTED){
//Stringtest1="selected";
// String test2="selected";
//String test3="selected;"
}
String record =null;
int recCount = 0;
try{
FileReader fr =new FileReader("H:/ems.txt");
BufferedReader br = new BufferedReader(fr);
record =new String();
while((record = br.readLine())!=null){
recCount++;
f.append("Line"+recCount+":"+record+"\n");// I modified here
//f.setText("Line"+recCount+":"+record);}
br.close();
fr.close();}
catch(IOException e){
e.printStackTrace();}
}
}
public static void main(String []args){
Exam pd=new Exam();
pd.pack();
}
}