java简易计数器.docVIP

package my_calculator; public class Mainclass { public static void main(String[] args) { MyFrame mf=new MyFrame(Calculator); } } ==================================================== package my_calculator; import java.awt.*; import java.awt.event.*; import java.math.*; public class MyFrame extends Frame { Label lab; ButtonPanel bp; int flag; double result; boolean pt; boolean equal; public MyFrame(String arg0) throws HeadlessException { super(arg0); Button bt=new Button(CE); pt=false; equal=true; result=0.0d; flag=0; lab=new Label(0,Label.RIGHT); bp=new ButtonPanel(); setLayout(new BorderLayout()); add(lab,BorderLayout.NORTH); add(bp,BorderLayout.CENTER); add(bt,BorderLayout.SOUTH); setLocation(200,200); setSize(300,300); setVisible(true); addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent arg0) { System.exit(0); } }); bt.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent arg0) { result=0.0d; lab.setText(0); } }); bp.bt[0].addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent arg0) { if(equal==false){ lab.setText(7); equal=true; } else if(pt||Double.parseDouble(lab.getText())!=0) lab.setText((new StringBuilder(String.valueOf(lab.getText()))).append(7).toString()); else lab.setText(7); } }); bp.bt[1].addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent arg0) { if(equal==false){ lab.setText(8); equal=true; } else if(pt||Double.parseDouble(lab.getText())!=0) lab.setText((new StringBuilder(String.valueOf(lab.getText()))).append(8).toString()); else lab.setText(8); } }); bp.bt[2].addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent arg0) { if(equal==false){ lab.setText(9); equal=true; } else if(pt||Double.parseDouble(lab.getText())!=0)