Java实现计算器程序

import java.awt.Button; import java.awt.Color; import java.awt.Container; import java.awt.Event; import java.awt.FlowLayout; import java.awt.GridLayout; import java.awt.Panel; import javax.swing.JFrame; import javax.swing.JTextField; public class CalculatorDemo extends JFrame{ /** * @param args */ JTextField answerText; Button pointButton,equalButton,plusButton,minusButton,clearButton,multiButton,divisionButton; Button[] b=new Button[10]; String currentOp ,preOp; String foreText,backText; boolean isFloat=false; public CalculatorDemo() { super("计算器"); setSize(400,400); Container container=getContentPane(); setVisible(true); Panel panel1=new Panel(); Panel panel2=new Panel(); Panel panel3=new Panel(); currentOp=new String(""); preOp=new String(""); foreText=new String(""); backText=new String(""); answerText=new JTextField(8); container.setBackground(Color.lightGray); //container.setForeground(Color.blue); for(int i=9;i>=0;i--) { b[i]=new Button(Integer.toString(i)); panel2.add(b[i]); } pointButton=new Button("."); equalButton=new Button("="); clearButton=new Button("清除"); clearButton.setForeground(Color.red); divisionButton=new Button("/"); divisionButton.setForeground(Color.red); multiButton=new Button("*"); plusButton=new Button("+"); plusButton.setForeground(Color.red); minusButton=new Button("-"); minusButton.setForeground(Color.red); container.setLayout(new FlowLayout()); panel1.setLayout(new FlowLayout()); panel2.setLayout(new GridLayout(4,3)); panel3.setLayout(new GridLayout(4,1)); panel1.add(answerText); panel1.add(clearButton); panel2.add(pointButton); panel2.add(equalButton); panel3.add(plusButton); panel3.add(minusButton); panel3.add(multiButton); panel3.add(divisionButton); container.add(panel1); container.add(panel2); container.add(panel3); } /*public boolean action(Event e,Object o) { String s=new String(""); for(int i=0;i<10;i++) { if(e.target==b[i]||e.target==pointButton) { if(e.target!=pointButton) { s=(String)o; doForeText(s); } if((e.target==pointButton)&&(!isFloat)) { isFloat=true; s=(String)o; if(foreText.equals("")) { foreText+="0."; } else { doForeText(s); } } } } if(e.target==clearButton) { doClear(); } if((e.target==multiButton)||(e.target==divisionButton)||(e.target==plusButton)||(e.target==minusButton)) { if(foreText!="") { currentOp=(String)o; doOprator(); } else { preOp=(String)o; } } if(e.target==equalButton) { doOprator(); } return true; } public void doOprator() { double dFore,dBack; Double d; if(preOp.equals("")) { backText=foreText; foreText=""; answerText.setText(backText); } else { dFore=(new Double(foreText)).doubleValue(); dBack=(new Double(backText)).doubleValue(); foreText=""; backText=answerText.getText(); if(preOp.equals("+")) { d=new Double((dBack+dFore)); answerText.setText(d.toString()); backText=d.toString(); } if(preOp.equals("-")) { d=new Double((dBack-dFore)); answerText.setText(d.toString()); backText=d.toString(); } if(preOp.equals("*")) { d=new Double((dBack*dFore)); answerText.setText(d.toString()); backText=d.toString(); } if(preOp.equals("/")) { if(dFore==0) { answerText.setText("除数不能为0"); return; } d=new Double((dBack/dFore)); answerText.setText(d.toString()); backText=d.toString(); } } preOp=currentOp; } public void doForeText(String s) { foreText+=s; answerText.setText(foreText); } public void doBackText(String s) { backText=foreText; foreText=""; answerText.setText(foreText); } public void doClear() { currentOp=""; preOp=""; foreText=""; backText=""; isFloat=false; answerText.setText(""); }*/ public static void main(String[] args) { // TODO Auto-generated method stub CalculatorDemo c=new CalculatorDemo(); } }