GUI练习：记事本小程序（打开文件+保存文件）

阳光穿透心脏的1/2处 2021-09-29 14:30 370阅读 0赞

【一】需求

GUI练习：打开文件+保存文件

【二】代码

import java.awt.*;
    import java.awt.event.*;
    import java.io.*;
    class MenuDemo2
    {
    	private Frame f;
    	private MenuBar bar;
    	private Menu fileMenu;
    	private MenuItem openItem,saveItem,closeItem;
    	private FileDialog openDia,saveDia;
    	private TextArea ta;
    	private File file;
    	MenuDemo2(){
    		init();
    	}
    
    	public void init(){
    		f=new Frame("练习");
    		f.setBounds(200,250,500,400);
    		
    		bar=new MenuBar();
    		f.setMenuBar(bar);
    		ta=new TextArea();
    		f.add(ta);
    		fileMenu=new Menu("文件");
    		bar.add(fileMenu);
    		openItem=new MenuItem("打开");
    		fileMenu.add(openItem);
    		saveItem=new MenuItem("保存");
    		fileMenu.add(saveItem);
    		closeItem=new MenuItem("关闭");
    		fileMenu.add(closeItem);
    		openDia=new FileDialog(f,"我要打开",FileDialog.LOAD);
    		saveDia=new FileDialog(f,"我要保存",FileDialog.SAVE);
    		f.setVisible(true);
    		myEvent();
    	}
    	private void myEvent(){
    		closeItem.addActionListener(new ActionListener(){
    			public void actionPerformed(ActionEvent e){
    				System.exit(0);
    			}
    		});
    		saveItem.addActionListener(new ActionListener(){
    			public void actionPerformed(ActionEvent e){
    				if(file==null){
    					saveDia.setVisible(true);
    					String dirPath=saveDia.getDirectory();
    					String fileName=saveDia.getFile();
    					//System.out.println(dirPath+"......"+fileName);
    					if(dirPath==null||fileName==null)
    						return ;
    					file=new File(dirPath,fileName);
    				}
    				try
    				{
    					BufferedWriter bufw=new BufferedWriter(new FileWriter(file));
    					String text=ta.getText();
    					bufw.write(text);
    					bufw.close();
    				}
    				catch (IOException io)
    				{
    					throw new RuntimeException("异常");
    				}
    				  
    			}
    		});
    		openItem.addActionListener(new ActionListener(){
    			public void actionPerformed(ActionEvent e){
    				openDia.setVisible(true);
    				String dirPath=openDia.getDirectory();
    				String fileName=openDia.getFile();
    				//System.out.println(dirPath+"......"+fileName);
    				if(dirPath==null||fileName==null)
    					return ;
    				ta.setText("");
    				File file=new File(dirPath,fileName);
    				try
    				{
    					BufferedReader bufr=new BufferedReader(new FileReader(file));
    					String line=null;
    					while((line=bufr.readLine())!=null){
    						ta.append(line+"\r\n");
    					}
    				}
    				catch (IOException io)
    				{
    					throw new RuntimeException("异常");
    				}
    				  
    			}
    		});
    		//窗口点击X,退出
    		f.addWindowListener(new WindowAdapter(){
    			public void windowClosing(WindowEvent e){
    				System.exit(0);
    			}
    		});
    	}
    	public static void main(String[] args) 
    	{
    		new MenuDemo2();
    	}
    }

【三】截图

保存文件：

![20190714204357671.png][]

![20190714204420835.png][]

打开文件：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RoZV9CZXN0X0hhY2tlcg_size_16_color_FFFFFF_t_70][]

[20190714204357671.png]: /images/20210811/3ef88b6825774441922ba2929749f8e0.png
[20190714204420835.png]: /images/20210811/4a3b4be5265c4dea942a755c75fbf5f2.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RoZV9CZXN0X0hhY2tlcg_size_16_color_FFFFFF_t_70]: /images/20210811/18fd623223de4f828f220c218e53e7ce.png