图像化设计-计算器

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Cal extends JFrame implements ActionListener{


	JTextField ta = new JTextField(20);
	//面版keys
	String[] numberStrings = {"7","8","9","/","4","5","6","*","1","2","3","-",".","0","=","+"};
	JButton keysButton[] = new JButton[numberStrings.length];
	//消除按钮
	JButton cancleButton = new JButton("cancle");
	public void init(){
		ta.setText("");
		//文本域在右边显示
		ta.setHorizontalAlignment(JTextField.RIGHT);
		
		JFrame f = new JFrame("calculate");
		f.add(ta, BorderLayout.NORTH);
		f.add(cancleButton,BorderLayout.EAST);
		
		Panel p = new Panel();
		p.setLayout(new GridLayout(4,4,3,3));
		//事件监听
		cancleButton.addActionListener(this);
		
		for (int i = 0; i < numberStrings.length; i++) {
			keysButton[i] = new JButton(numberStrings[i]);
			p.add(keysButton[i]);
			//事件监听
			keysButton[i].addActionListener(this);
		}
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.add(p, BorderLayout.CENTER);
		f.setLocation(new Point(500,500));
		f.setSize(new Dimension(200,100));
		f.pack();
		f.setVisible(true);
	}
	public static void main(String[] args) {
		new Cal().init();
	}
	//获取TextField的值
	public String getNum(){
		return ta.getText();
	}
	
	String lastNum = "";
	String operatorString = "";
	@Override
	public void actionPerformed(ActionEvent e) {
		String label = e.getActionCommand();
		String firstNum = getNum();
		
		if("0123456789.".indexOf(label)>=0){
			firstNum+=label;
			ta.setText(firstNum);
		}else if("+-*/".indexOf(label)>=0){
			operatorString = label;
			lastNum=getNum();
			ta.setText("");
		}else if("=".equals(label)){
			ta.setText(""+result(lastNum,firstNum,operatorString));
		}else if("cancle".equals(label)){
			ta.setText("");
		}
	}
	
	//显示结果
	public Double result(String first,String last,String operator){
		double res = 0;
		//为空的处理
		if("".equals(last)||"".equals(first)){
			last="0";
			first="0";
		}
		if("+".equals(operator)){
			res = Double.valueOf(first) + Double.valueOf(last);
		}else if("-".equals(operator)){
			res = Double.valueOf(first) - Double.valueOf(last);
		}else if("*".equals(operator)){
			res = Double.valueOf(first) * Double.valueOf(last);
		}else if("/".equals(operator)){
			res = Double.valueOf(first) /  Double.valueOf(last);
		}
		return res;
	}
}

大家一起学习！！！