Java实现记事本
题目
利用GUI实现一个简单的记事本（notepad），即打开文件，文字内容显示在界面上；
允许对文字内容进行编辑，并可以保存到文件。
代码
class notPadcontainer{
public Boolean visible = false;
//组件定义成属性
public JFrame notPadFrame;
public JMenuBar notPadMenuBar;
public JMenu firMenu;
public JMenu secMenu;
public JMenu thirMenu;
public JMenu fourMenu;
public JMenuItem buildItem;
public JMenuItem openItem;
public JMenuItem reserveItem;
public JMenuItem paperSetItem;
public JMenuItem clearItem;
public JMenuItem aboutItem;
public JMenuItem fontItem20;
public JMenuItem fontItem40;
public JTextArea textArea;
public JScrollPane textScrollPane;
/*
* 无参构造函数
* 创建组件 初始化组件
*/
notPadcontainer(){
//窗体Frame
this.notPadFrame = new JFrame("notePad by fishers"); //设置窗体 名字为notePad
this.notPadFrame.setLayout(new BorderLayout()); //边界布局方式
this.notPadFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //设置关闭框
this.notPadFrame.setSize(500,500); //设置窗口大小
//菜单组件
this.notPadMenuBar = new JMenuBar();
this.firMenu = new JMenu("文件");
this.thirMenu = new JMenu("字体");
this.secMenu = new JMenu("编辑");
this.fourMenu = new JMenu("帮助");
//create JMenuItem for the First menu
this.buildItem = new JMenuItem("新建");
this.openItem = new JMenuItem("打开");
this.reserveItem = new JMenuItem("保存");
this.paperSetItem = new JMenuItem("页面设置");
//create JMenuItem for the sec thir four menu
this.clearItem = new JMenuItem("清空");
this.aboutItem = new JMenuItem("关于");
this.fontItem20 = new JMenuItem("字体20号");
this.fontItem40 = new JMenuItem("字体40号");
//文本组件
this.textArea = new JTextArea();
this.textScrollPane = new JScrollPane(textArea);
textArea.setFont(new Font("宋体",Font.PLAIN,20)); //默认20号字体
ItemAdd();
runListener();
}
//添加组件
public void ItemAdd(){
//添加JMenu到JMenuBar
notPadMenuBar.add(firMenu);
notPadMenuBar.add(secMenu);
notPadMenuBar.add(thirMenu);
notPadMenuBar.add(fourMenu);
//添加JMenuItem到第一个菜单
firMenu.add(buildItem);
firMenu.add(openItem);
firMenu.add(reserveItem);
firMenu.add(paperSetItem);
secMenu.add(clearItem);
thirMenu.add(fontItem20);
thirMenu.add(fontItem40);
fourMenu.add(aboutItem);
//notPadFrame中添加各个组件
this.notPadFrame.setJMenuBar(notPadMenuBar);
this.notPadFrame.add(textScrollPane,BorderLayout.CENTER);
}
/*
* 事件监听代码部分
*/
public void runListener() {
//新建文件 = 清空。。
buildItem.addActionListener( e -> {
textArea.setText("");
});
//打开文件
openItem.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
//设置弹出框 FileDialog
FileDialog saveFiledialog = new FileDialog(notPadFrame,"打开文件",FileDialog.LOAD);
saveFiledialog.setVisible(true);
String fileDir = saveFiledialog.getDirectory(); //拿到目录
String fileName = saveFiledialog.getFile(); //拿到文件名
// System.out.println(fileDir);
// System.out.println(fileName);
File openFile = new File(fileDir,fileName); //使用File类创建新文件对象
try {
FileReader freader = new FileReader(openFile); //字符流
StringBuffer tempBuffer = new StringBuffer();//StringBuffer可变
int len = 0; //下面使用read方法读取
while((len = freader.read()) != -1) {
tempBuffer.append((char)len); //append方法加入StringBuffer
}
String openString = new String(tempBuffer.toString());
textArea.setText(openString);
freader.close();//关闭流
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
//保存文件
reserveItem.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
FileDialog saveFiledialog = new FileDialog(notPadFrame,"保存文件",FileDialog.SAVE);//父级frame 标题 mode
saveFiledialog.setVisible(true);
String fileDir = saveFiledialog.getDirectory();
String fileName = saveFiledialog.getFile();
System.out.println(fileDir);
System.out.println(fileName);
String ContentString = textArea.getText();
File saveFile = new File(fileDir,fileName);
try {
FileWriter fWriter = new FileWriter(saveFile); //使用字符流写文件
fWriter.write(ContentString); //写文件
fWriter.close(); //关闭流
}catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
//清空文件
clearItem.addActionListener( e -> {
textArea.setText("");
});
//监听关于
aboutItem.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
JFrame aboutFrame = new JFrame("关于"); //新建窗口
aboutFrame.setLayout(new BorderLayout());
aboutFrame.setSize(300,115);
aboutFrame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);//设置隐藏窗口
JPanel panel = new JPanel();
JLabel label = new JLabel("不会换行、中文乱码的记事本");
JPanel panel2 = new JPanel();
JLabel label2 = new JLabel("Copyright © 2019 fishers");
panel.add(label);
panel2.add(label2);
aboutFrame.add(panel,BorderLayout.CENTER);
aboutFrame.add(panel2,BorderLayout.PAGE_START);
aboutFrame.setVisible(true);
}
});
fontItem20.addActionListener(e->{
textArea.setFont(new Font("宋体",Font.PLAIN,20));
});
fontItem40.addActionListener(e->{
textArea.setFont(new Font("宋体",Font.PLAIN,40));
});
}
//setVisible:设置窗口显示
public void setVisible(Boolean visible) {
this.visible = visible;
this.notPadFrame.setVisible(this.visible);
}
}
public class notePad {
public static void main(String[] args) {
notPadcontainer oneNote = new notPadcontainer();
oneNote.setVisible(true);
}
}