currencychange.java

用java实现的人民币和美元汇率转换的程序

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class CurrencyChange implements ActionListener{
	JFrame frame;
	JTextField trmb;
	JTextField tdollar;
	JTextField texchange;
	JButton btnexRmb;
	JButton btnexDollar;
	JLabel l1;
	JLabel lrmb;
	JLabel ldollar;
	Panel p1;
	Panel p2;
	Panel p3;
	public CurrencyChange() {
		frame=new JFrame("人民币与美元的转换");
		Container cp=new Container();
		cp=frame.getContentPane();
	//	frame.setLayout(null);
		frame.setSize(250,200);
		trmb=new JTextField(15);
		tdollar=new JTextField(15);
		texchange=new JTextField(10);
		texchange.setText("7.7496");
		texchange.setEditable(false);
		btnexRmb=new JButton("人民币");
		btnexDollar=new JButton("美元");
		l1=new JLabel("汇率值");
		lrmb=new JLabel("人民币");
		ldollar=new JLabel("美元");
		btnexRmb.addActionListener(this);
		btnexDollar.addActionListener(this);
	    p1=new Panel();
		p2=new Panel();
		p3=new Panel();
		p1.add(l1,BorderLayout.WEST);
		p1.add(texchange,BorderLayout.SOUTH);
		//l1.setBounds(20,10,30,30);
	//	exchange.setBounds(40,10,90,30);
	   p2.setLayout(new FlowLayout());
	   p2.add(lrmb);
	   p2.add(trmb);
	   p2.add(ldollar);
	   p2.add(tdollar);
    //	   rmb.setBounds(20,30,40,40);
	//	dollar.setBounds(70,30,90,40);
		p3.add(btnexRmb,BorderLayout.WEST);
		p3.add(btnexDollar,BorderLayout.SOUTH);
	//	exRmb.setBounds(20,50,40,70);
	//	exDollar.setBounds(70,50,90,70);
		cp.add(p1,BorderLayout.NORTH);
		cp.add(p2,BorderLayout.CENTER);
		cp.add(p3,BorderLayout.SOUTH);
	    frame.addWindowListener(new WindowAdapter(){
		public void windowClosing(WindowEvent e){
			System.exit(0);
		}
	});
		frame.setVisible(true);
	}
  public void actionPerformed(ActionEvent e){
  JButton button=new JButton();
  button=(JButton)e.getSource();
  double value;
  String str=new String();
  double inexchange=Double.parseDouble(texchange.getText());//转换成整型
  if(button==btnexDollar){
  	 value=Double.parseDouble(trmb.getText())*inexchange; 
  	 str=Double.toString(value);
  	 tdollar.setText(str);
  	 
  }	
  else if(button==btnexRmb){
  	value=Double.parseDouble(tdollar.getText())/inexchange;
  	str=Double.toString(value);
  	trmb.setText(str);
  }
  }	
  public static void main(String arg[]){
  	new CurrencyChange();
  }
}