JAVA 教程和源码

import java.awt.*; import java.awt.event.*; public class calculator implements ActionListener{ Frame f; Panel p1,p2; TextField op1,op2,result; Button calc,clearb; public void show(){ f = new Frame("一个简单的计算器"); f.setSize(240,180); f.setLocation(300,200); //设置窗口初始位置 f.setBackground(Color.lightGray); f.setLayout(new FlowLayout()); //设置布局管理器 result = new TextField(20); result.setEditable(false); //不允许用户编辑 op1 = new TextField("0",4); op2 = new TextField("0",4); p1=new Panel(); p1.add(op1); p1.add(new Label("+")); p1.add(op2); f.add(result); f.add(p1); calc = new Button(" = "); clearb = new Button("Clear"); p2=new Panel(); p2.add(calc); p2.add(clearb); f.add(p2); calc.addActionListener(this); //为按钮注册事件监听程序 clearb.addActionListener(this); f.addWindowListener(new WinClose()); //为框架f注册事件监听程序 f.setVisible(true); } public void actionPerformed(ActionEvent e){ //实现ActionListener接口中的方法，单击按钮时产生该事件 if(e.getSource()==clearb){ //获得产生事件的对象 result.setText(""); op1.setText("0"); op2.setText("0"); } else //获取按钮标签,重新设置文本内容 if(e.getSource()==calc){ int sum,x,y; String S1=op1.getText().trim(); String S2=op2.getText().trim(); String tempS; x=Integer.parseInt(S1); //取得左操作数 y=Integer.parseInt(S2); sum=x+y; result.setText(String.valueOf(x)+"+"+String.valueOf(y)+"="+String.valueOf(sum)); } } public static void main(String arg[]){ (new calculator()).show(); } } class WinClose implements WindowListener{ public void windowClosing(WindowEvent e){ System.exit(0); } public void windowOpened(WindowEvent e){ } ; //窗口打开时调用 public void windowIconified(WindowEvent e){ }; //窗口图标化时调用 public void windowDeiconified(WindowEvent e){ }; //窗口非图标化时调用 public void windowClosed(WindowEvent e){ }; //窗口关闭时调用 public void windowActivated(WindowEvent e){ }; //窗口激活时调用 public void windowDeactivated(WindowEvent e){ }; //窗口非激活时调用 } /*import java.awt.*; import java.awt.event.*; public class calculator implements ActionListener { Frame f; TextField tf1; Button b1,b2,b3,b4,b5; public void display() { f = new Frame("Calculation"); f.setSize(260,150); f.setLocation(320,240); //设置窗口初始位置 f.setBackground(Color.lightGray); f.setLayout(new FlowLayout(FlowLayout.LEFT));//改变布局且左对齐 tf1 = new TextField(30); tf1.setEditable(false); //只能显示，不允许编辑 f.add(tf1); b1 = new Button("1"); b2 = new Button("2"); b3 = new Button("+"); b4 = new Button("C"); b5 = new Button("="); f.add(b1); f.add(b2); f.add(b3); f.add(b4); f.add(b5); b1.addActionListener(this); //为按钮b1注册事件监听程序 b2.addActionListener(this); b3.addActionListener(this); b4.addActionListener(this); b5.addActionListener(this); f.addWindowListener(new WinClose()); //为框架f注册事件监听程序 f.setVisible(true); } public void actionPerformed(ActionEvent e) { //实现ActionListener接口中的方法，单击按钮时产生该事件 if (e.getSource()==b4) //获得产生事件的对象 tf1.setText(""); else //获取按钮标签,重新设置文本内容 if(e.getSource()==b5) { int sum,a,b; String textS=tf1.getText().trim(); String tempS; int founded=textS.indexOf('+'); //返回“+”在串的位置 if(founded==-1) //串中不含“+” tf1.setText("not a formula"); else { a=Integer.parseInt(textS.substring(0,founded));//取得“+”前面的字符作为左操作数 // tf1.setText(String.valueOf(a)); tempS=textS.substring(founded+1);//取得“+”右面的字符作为右操作数 b=Integer.parseInt(tempS); sum=a+b; tf1.setText(String.valueOf(a)+"+"+String.valueOf(a)+"="+String.valueOf(sum)); //tf1.setText(String.valueOf(sum)); } } else tf1.setText(tf1.getText()+e.getActionCommand()); } public static void main(String arg[]) { (new calculator()).display(); } } class WinClose extends WindowAdapter { public void windowClosing(WindowEvent e) { //覆盖WindowAdapter类中同名方法，单击窗口关闭按钮时产生该事件 System.exit(0); //结束程序运行，关闭窗口 } }*/