import java.io.*;
import java.awt.*;
import java.awt.event.*;
public class frm123 extends Frame
{
public static void main(String args[])
{
frm123frm frm=new frm123frm();
}
}
public class frm123frm extends Frame implements ActionListener
{
FileDialog op,sv;
Button btn1,btn2,btn3;
TextArea tarea;
frm123frm()
{
super("我的专用记事本");
setLayout(null);
setBackground(Color.black);
setSize(600,300);
setVisible(true);
btn1=new Button("打开");
btn2=new Button("保存");
btn3=new Button("关闭");
tarea=new TextArea("");
add(btn1);add(btn2);add(btn3);add(tarea);
tarea.setBounds(30,50,460,220);
btn1.setBounds(520,60,50,30);
btn2.setBounds(520,120,50,30);
btn3.setBounds(520,180,50,30);
op=new FileDialog(this,"打开",FileDialog.LOAD);
sv=new FileDialog(this,"保存",FileDialog.SAVE);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);}});
btn1.addActionListener(this);
btn2.addActionListener(this);
btn3.addActionListener(this);
}
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==btn1)
{
String str;
op.setVisible(true);
try
{
File f1=new File(op.getDirectory(),op.getFile());
FileReader fr=new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
tarea.setText("");
while((str=br.readLine())!=nill)tarea.append(str+'\n');
fr.close();
}
catch(Exception e1)
{
}
}
if(e.getSource()==btn2)
{
sv.setVisible(true);
try
{
File f1=new File(sv.getDirectory(),sv.getFile());
FileWriter fw= new FileWriter(f1);
BufferedWriter bw = new BufferedWriter(fw);
String gt=tarea.getText();
bw.write(gt,0,gt.length());
bw.flush();
fw.close();
}
catch(Exception e2)
{
}
}
if(e.getSource()==3)
{
System.exit(0);
}
}
----------------解决方案--------------------------------------------------------
public class只能有一个，但是你有2个，应该去掉一个public
while((str=br.readLine())!=nill)tarea.append(str+'\n');//改成null
if(e.getSource()==3)//一个是Object,一个是int，这样无法比较
----------------解决方案--------------------------------------------------------
那问题是粗心弄成的.
我改了,但还是不行
import java.io.*;
import java.awt.*;
import java.awt.event.*;
public class frm123 extends Frame
{
public static void main(String args[])
{
frm123frm frm=new frm123frm();
}
}
class frm123frm extends Frame implements ActionListener
{
FileDialog op,sv;
Button btn1,btn2,btn3;
TextArea tarea;
frm123frm()
{
super("我的专用记事本");
setLayout(null);
setBackground(Color.black);
setSize(600,300);
setVisible(true);
btn1=new Button("打开");
btn2=new Button("保存");
btn3=new Button("关闭");
tarea=new TextArea("");
add(btn1);add(btn2);add(btn3);add(tarea);
tarea.setBounds(30,50,460,220);
btn1.setBounds(520,60,50,30);
btn2.setBounds(520,120,50,30);
btn3.setBounds(520,180,50,30);
op=new FileDialog(this,"打开",FileDialog.LOAD);
sv=new FileDialog(this,"保存",FileDialog.SAVE);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);}});
btn1.addActionListener(this);
btn2.addActionListener(this);
btn3.addActionListener(this);
}
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==btn1)
{
String str;
op.setVisible(true);
try
{
File f1=new File(op.getDirectory(),op.getFile());
FileReader fr=new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
tarea.setText("");
while((str=br.readLine())!=null)tarea.append(str+'\n');
fr.close();
}
catch(Exception e1)
{
}
}
if(e.getSource()==btn2)
{
sv.setVisible(true);
try
{
File f1=new File(sv.getDirectory(),sv.getFile());
FileWriter fw= new FileWriter(f1);
BufferedWriter bw = new BufferedWriter(fw);
String gt=tarea.getText();
bw.write(gt,0,gt.length());
bw.flush();
fw.close();
}
catch(Exception e2)
{
}
}
if(e.getSource()==btn3)
{
System.exit(0);
}
}
----------------解决方案--------------------------------------------------------
还有你的括号不配对，最后一行加一个},public void actionPerformed(ActionEvent e)前面删一个}
----------------解决方案--------------------------------------------------------
import java.io.*;
import java.awt.*;
import java.awt.event.*;
public class Frm123
{
public static void main(String args[])
{
Frm123frm frm=new Frm123frm();
}
}
class Frm123frm extends Frame implements ActionListener
{
private FileDialog op,sv;
private Button btn1,btn2,btn3;
private TextArea tarea;
public Frm123frm()
{
super("我的专用记事本");
setLayout(null);
setBackground(Color.black);
setSize(600,300);
setVisible(true);
btn1=new Button("打开");
btn2=new Button("保存");
btn3=new Button("关闭");
tarea=new TextArea("");
add(btn1);add(btn2);add(btn3);add(tarea);
tarea.setBounds(30,50,460,220);
btn1.setBounds(520,60,50,30);
btn2.setBounds(520,120,50,30);
btn3.setBounds(520,180,50,30);
op=new FileDialog(this,"打开",FileDialog.LOAD);
sv=new FileDialog(this,"保存",FileDialog.SAVE);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);}});
btn1.addActionListener(this);
btn2.addActionListener(this);
btn3.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==btn1)
{
String str;
op.setVisible(true);
try
{
File f1=new File(op.getDirectory(),op.getFile());
FileReader fr=new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
tarea.setText("");
while((str=br.readLine())!=null)tarea.append(str+'\n');
fr.close();
}
catch(Exception e1)
{
}
}
if(e.getSource()==btn2)
{
sv.setVisible(true);
try
{
File f1=new File(sv.getDirectory(),sv.getFile());
FileWriter fw= new FileWriter(f1);
BufferedWriter bw = new BufferedWriter(fw);
String gt=tarea.getText();
bw.write(gt,0,gt.length());
bw.flush();
fw.close();
}
catch(Exception e2)
{
}
}
if(e.getSource()==btn3)
{
System.exit(0);
}
}
}
这样就行了,编程要养成良好的习惯，类名第一个字母大写，类的成员变量一般声明为private类型的
----------------解决方案--------------------------------------------------------
菜鸟 还看不懂 但知道的习惯地重要性
----------------解决方案--------------------------------------------------------