GUI-02

最新推荐文章于 2025-06-13 02:11:54 发布

原创最新推荐文章于 2025-06-13 02:11:54 发布 · 501 阅读

CC 4.0 BY-SA版权

添加菜单：

例：
import java.awt.*;
import java.awt.event.*;
class MyMenuDemo
{
private Frame f;
private MenuBar mb;
private Menu m, subMenu;//里面还可以添加子条目
private MenuItem closeItem, subItem;

MyMenuDemo()
{
  init();
}
public void init()
{
  f = new Frame("我的窗口");
  f.setBounds(300, 100, 600, 500);
  f.setLayout(new FlowLayout()); //流式布局

  mb = new MenuBar();
  m = new Menu("文件");
  closeItem = new MenuItem("退出");
  subItem = new MenuItem("小菜单");
  subMenu = new Menu("大菜单");

  subMenu.add(subItem);//在Menu中可以添加MenuItem

  m.add(subMenu);//在Menu中添加Menu,可见Menu是可以扩展的

  m.add(closeItem);

  mb.add(m);
  f.setMenuBar(mb);//在窗口中添加MenuBar

  MyEvent();//添加事件
  f.setVisible(true);
}
public void MyEvent()
{
  closeItem.addActionListener(new ActionListener() //在退出菜单添加事件
  {
   public void actionPerformed(ActionEvent e)
   {
    System.exit(0);
   }
  });
  f.addWindowListener(new WindowAdapter() //添加窗口事件
  {
   public void windowClosing(WindowEvent e)
   {
    System.exit(0);
   }
  });
}

public static void main(String[] args)
{
new MyMenuDemo();
}

}

--------------------------------------------------------------------------------------------------

文件打开保存，使用默认的边界式布局

import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class MyMenuTest
{
private Frame f;
private TextArea ta;
private MenuBar bar;
private Menu fileMenu;
private MenuItem openItem, saveItem, closeItem, subItem;

private FileDialog openDia, saveDia;
private File file;

MyMenuTest()
{
  init();
}
public void init()
{
  f = new Frame("my window");
  f.setBounds(300, 100, 600, 500);
  //f.setLayout(new FlowLayout());

  bar = new MenuBar();
  ta = new TextArea();

  fileMenu = new Menu("文件");

  openItem = new MenuItem("打开");
  saveItem = new MenuItem("保存");
  closeItem = new MenuItem("退出");

  fileMenu.add(openItem);
  fileMenu.add(saveItem);
  fileMenu.add(closeItem);
  bar.add(fileMenu);

  f.setMenuBar(bar);

  openDia = new FileDialog(f, "我要打开", FileDialog.LOAD);//有两种模式load和save
  saveDia = new FileDialog(f, "我要保存", FileDialog.SAVE);

  f.add(ta);

  myEvent();

  f.setVisible(true);
}

private void myEvent()
{
  saveItem.addActionListener(new ActionListener() //保存
  {
   public void actionPerformed(ActionEvent e)
   {
    if(file==null)//如果文件不存在，则弹出保存对话框
    {
     saveDia.setVisible(true);//显示对话框

     String dirPath = saveDia.getDirectory(); //文件路径
     String fileName = saveDia.getFile(); //文件名
     if(dirPath==null || fileName==null)
      return;
     file = new File(dirPath, fileName);
    }

    try
    {
     BufferedWriter bufw = new BufferedWriter(new FileWriter(file));

     String text = ta.getText();//获取文本中的内容

     bufw.write(text);//写到文件中
     //bufw.flush();
     bufw.close();
    }
    catch(IOException ex)
    {
     throw new RuntimeException();
    }
   }
  });

  openItem.addActionListener(new ActionListener() //在打开菜单上添加事件
  {
   public void actionPerformed(ActionEvent e)
   {
    openDia.setVisible(true);//显示打开对话框
    String dirPath = openDia.getDirectory();//获取路径
    String fileName = openDia.getFile();//获取文件名
    //System.out.println(dirPath+"..."+fileName);

    if(dirPath==null || fileName==null)//增加健壮性判断
     return;

    ta.setText("");//清空文本区域的内容
    file = new File(dirPath, fileName);

    try
    {
     BufferedReader bufr = new BufferedReader(new FileReader(file));
     String line = null;

     while((line=bufr.readLine()) != null)//读取文件内容
     {
      ta.append(line+"\r\n");//添加一行并回车换行
     }
     bufr.close();
    }
    catch(IOException ex)
    {
     throw new RuntimeException("读取失败");
    }


   }
  });

  closeItem.addActionListener(new ActionListener()//退出菜单事件
  {
   public void actionPerformed(ActionEvent e)
   {
    System.exit(0);
   }
  });

  f.addWindowListener(new WindowAdapter()
  {
   public void windowClosing(WindowEvent e)
   {
    System.exit(0);
   }
  });
}

public static void main(String[] args)
{
  new MyMenuTest();
}
}