java图形界面实现的至少三种以上汇率转换

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package javaexchange; import java.awt.*; import java.awt.event.*; import javax.swing.*; /** * * @author chun */ public class RateExchange extends JFrame implements ItemListener, ActionListener{ public static void main(String[] args) { RateExchange e=new RateExchange("汇率转换"); } Choice choice1, choice2; float sum; float rate[] = { 1, (float) 6.5431, (float) 84.2800, (float) 0.6935, (float) 0.9563, (float) 0.9533, (float) 0.6132, (float) 29.112, (float) 7.7727 }; String s[] = { "USD ", "CNY", "JPY", "EUR", "CAD", "AUD", "GBP", "TWD", "HKD" }; JLabel lab1=new JLabel("兑换金额"), lab2=new JLabel("要兑换的币种"), lab3=new JLabel("兑换成的币种"), lab4=new JLabel("兑换后金额"); JTextArea ta1=new JTextArea(""), ta2=new JTextArea(""); JButton bt; double db1, db2; String str1, str2; private RateExchange(String string) { super(string); setBounds(400, 150, 300, 400); Container ctp = getContentPane(); ctp.setBackground(Color.lightGray); ctp.setLayout(null); setSize(400,300); setLocation(400,300); setVisible(true); lab1.setBounds(10, 10, 150, 20); ta1.setBounds(80, 10, 130, 20); lab2.setBounds(10, 60, 80, 20); choice1 = new Choice(); for (int i=0; i< s.length; i++) { choice1.addItem(s[i]); } choice1.setBounds(100, 60, 90, 80); choice1.addItemListener(this); lab3.setBounds(10, 110, 90, 20); choice2 = new Choice(); for (int i = 0; i < s.length; i++) { choice2.addItem(s[i]); } choice2.setBounds(100, 110, 90, 80); choice2.addItemListener(this); lab4.setBounds(10, 210, 150, 20); bt = new JButton("兑换"); bt.setBounds(120, 160, 60, 20); bt.addActionListener(this); ta2.setBounds(80, 210, 130, 20); add(lab1); add(ta1); add(lab2); add(choice1); add(lab3); add(choice2); add(bt); add(lab4); add(ta2); addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { System.exit(0); } }); } public void itemStateChanged(ItemEvent e) { if (e.getSource() == choice1) { //判断动作事件是否由choice1发生 int cbx1 = choice1.getSelectedIndex();//获取当前选择的下标 } if (e.getSource()==choice2) {//判断动作事件是否由choice1发生 int cbx2=choice2.getSelectedIndex(); } } public void actionPerformed(ActionEvent e) { String sum1; String text = ta1.getText(); sum=Float.parseFloat(text);//将取得的字符串转换为浮点数 int cbx1=choice1.getSelectedIndex(); int cbx2=choice2.getSelectedIndex(); java.text.DecimalFormat df = new java.text.DecimalFormat("0.000000");//格式化十进制数字输出 sum1=df.format((double) rate[cbx2]/(double) rate[cbx1] * sum); ta2.setText(sum1);//把转换后的值给ta2 } }