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);

}

}