calculator.java

简单的计算器

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class calculator extends Frame{
    public static void main(String[] args){
        new CFrame("郭敏的计算器");
       
    }

}
class CFrame extends Frame{
	Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17;
    JTextField tf;
    //String text = ""; 
    StringBuffer str;
    double x,y;
	int z;
    
    public CFrame (String s){
        super(s);
        setLayout(new BorderLayout()); 
        setLocation(350,250);
        setSize(200,250);
        
         tf= new JTextField("0",300);
         b0=new Button("C");
         b0.setForeground(Color.red);
 		 b0.addActionListener(new behavior()); 
         b1=new Button("1");
         b1.setForeground(Color.blue);
 		 b1.addActionListener(new behavior()); 
         b2=new Button("2");
         b2.setForeground(Color.blue);
 		 b2.addActionListener(new behavior());
         b3=new Button("3");
         b3.setForeground(Color.blue);
 		 b3.addActionListener(new behavior()); 
         b4=new Button("+");
         b4.setForeground(Color.red);
 		 b4.addActionListener(new behavior()); 
         b5=new Button("4");
         b5.setForeground(Color.blue);
 		 b5.addActionListener(new behavior()); 
         b6=new Button("5");
         b6.setForeground(Color.blue);
 		 b6.addActionListener(new behavior()); 
         b7=new Button("6");
         b7.setForeground(Color.blue);
 		 b7.addActionListener(new behavior()); 
         b8=new Button("-");
         b8.setForeground(Color.red);
 		 b8.addActionListener(new behavior()); 
         b9=new Button("7");
         b9.setForeground(Color.blue);
 		 b9.addActionListener(new behavior()); 
         b10=new Button("8");
         b10.setForeground(Color.blue);
 		 b10.addActionListener(new behavior()); 
         b11=new Button("9");
         b11.setForeground(Color.blue);
 		 b11.addActionListener(new behavior());
         b12=new Button("*");
         b12.setForeground(Color.red);
 		 b12.addActionListener(new behavior());
         b13=new Button("0");
         b13.setForeground(Color.blue);
 		 b13.addActionListener(new behavior()); 
         b14=new Button(".");
         b14.setForeground(Color.blue);
 		 b14.addActionListener(new behavior()); 
         b15=new Button("=");
         b15.setForeground(Color.red);
 		 b15.addActionListener(new behavior());
         b16=new Button("/");
         b16.setForeground(Color.red);
 		 b16.addActionListener(new behavior());//实例化所有的按钮，设置颜色，注册动作监听器 
        
        Panel p1 = new Panel(new BorderLayout());
        Panel p2=new Panel(new GridLayout(4,4));
        Panel p3=new Panel(new BorderLayout());
        str=new StringBuffer(); 
        p1.add(tf);
        p2.add(b1); p2.add(b2);p2.add(b3);p2.add(b4);
        p2.add(b5); p2.add(b6);p2.add(b7);p2.add(b8);
        p2.add(b9); p2.add(b10);p2.add(b11);p2.add(b12);
        p2.add(b13); p2.add(b14);p2.add(b15);p2.add(b16);
        p3.add(b0);
        add(p1,"North");add(p2,"Center");add(p3,"South");
        addWindowListener(new WindowAdapter(){ 
             public void windowClosing(WindowEvent e1){ 
             System.exit(0); 
             } 
             }); 
        setVisible(true);
    }


class behavior implements ActionListener{
	public void actionPerformed(ActionEvent e2){
		try{
			if(e2.getSource()==b0){
				tf.setText("0");
				str.setLength(0);
			}//选择清零
			else if(e2.getSource()==b4){
			x=Double.parseDouble(tf.getText().trim());
			str.setLength(0);
			y=0d;
			z=0;
			}//加功能
			else if(e2.getSource()==b8){
				x=Double.parseDouble(tf.getText().trim());
				str.setLength(0);
				y=0d;
				z=1;
			}//减功能
			else if(e2.getSource()==b12){
				x=Double.parseDouble(tf.getText().trim());
				str.setLength(0);
				y=0d;
				z=2;
			}//乘功能
			else if(e2.getSource()==b16){
				x=Double.parseDouble(tf.getText().trim());
				str.setLength(0);
				y=0d;
				z=3;
			}//除功能
			else if(e2.getSource()==b15){
				str.setLength(0);
				switch(z){
				case 0:tf.setText(""+(x+y));break;
				case 1:tf.setText(""+(x-y));break;
				case 2:tf.setText(""+(x*y));break;
				case 3:tf.setText(""+(x/y));break;
				}
			}//实现等号运算
			else if(e2.getSource()==b14)//单击"."按钮输入小数 
			{ 
			if(tf.getText().trim().indexOf(".")!=-1)//判断字符串中是否已经包含了小数点 
			{ 

			} 
			else//如果没数点有小 
			{ 
			if(tf.getText().trim().equals("0"))//如果初时显示为0 
			{ 
			str.setLength(0); 
			tf.setText((str.append("0"+e2.getActionCommand())).toString()); 
			} 
			else if(tf.getText().trim().equals(""))//如果初时显示为空则不做任何操作 
			{ 
			} 
			else 
			{ 
			tf.setText(str.append(e2.getActionCommand()).toString()); 
			} 
			} 

			y=0d; 

			} 
			else//其他的数字键 
			{ 
			tf.setText(str.append(e2.getActionCommand()).toString()); 
			y=Double.parseDouble(tf.getText().trim()); 
			} 
		}
		
			
		catch(NumberFormatException e){ 
			tf.setText("数字格式异常"); 
			} 
			catch(StringIndexOutOfBoundsException e){
				tf.setText("字符串索引越界");
			}//捕获异常
		
	}
  }
}