Java编写计算器的几种常见的做法.doc

import java.awt.*; import java.awt.event.*; public class MyCalculator { private Frame f; private TextField tf = new TextField(30); private long result; private boolean append=false; private char operator==; private Button[] btn=new Button[15]; public MyCalculator() { initComponent(); } private void initComponent() { f = new Frame(My Calculator V1.0); f.setLayout(new BorderLayout()); //The frame uses BorderLayout f.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent evt) { System.exit(0); } }); Panel centerPanel = new Panel(); centerPanel.setLayout(new GridLayout(5, 3)); //The panel uses GridLayout NumberListener nl=new NumberListener(); OperatorListener ol=new OperatorListener(); btn[10]=new Button(+); btn[11]=new Button(-); btn[12]=new Button(*); btn[13]=new Button(/); btn[14]=new Button(=); for (int i=0;i=9;i++){ btn[i]=new Button(String.valueOf(i)); centerPanel.add(btn[i]); btn[i].addActionListener(nl); if (i%2==1){ centerPanel.add(btn[(i+19)/2]); btn[(i+19)/2].addActionListener(ol); } } f.add(centerPanel, BorderLayout.CENTER); Panel northPanel = new Panel(); tf.setEditable(false); northPanel.add(tf); f.add(northPanel, BorderLayout.NORTH); } public void go() { f.pack(); f.setVisible(true); } public static void main(String[] args) { new MyCalculator().go(); } /** *采用成员内部类方式，实现监听器接口，方便访问主类内类内部成员。 *此类负责数字按钮Action事件监听和处理 */ class NumberListener implements ActionListener{ public void actionPerformed(ActionEvent e){ if (!append) { tf.setText(); append=true; } String s=tf.getText(); s+=e