package caofeng;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;


import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;

public class Calculator implements ActionListener{
    private String str = "";
    private JTextArea jtf;
    private JFrame frame;
    private Container contentPane;
    private String []names={"1","2","3","+","退格",
                     "4","5","6","-","刷新",
                     "7","8","9","*",".",
                     "0","(",")","/","="
    };
    private JButton []buttons=new JButton[20];
    public Calculator(){  //构造方法
        frame=new JFrame("Calculator"); //定义一个框架
        contentPane=frame.getContentPane(); //获取内容格
        
        JPanel jp1=new JPanel();  //定义一个面板
        jtf=new JTextArea("",7,43);
        jtf.setEditable(false);
        jp1.add(jtf);
        
        JPanel jp2=new JPanel();
        jp2.setLayout(new GridLayout(4,5,5,5));  //设置布局管理器
        this.fillJP2(jp2);
        
        contentPane.add(jp1,BorderLayout.NORTH);
        contentPane.add(jp2,BorderLayout.SOUTH);
        
        frame.setSize(500,300);
        frame.setVisible(true);
    }
    
    private void fillJP2(JPanel j){   //添加组件
        for(int i=0;i<names.length;i++){
            buttons[i]=new JButton(names[i]);
            j.add(buttons[i]);
            buttons[i].addActionListener(this);
        }
    }
    
    private boolean isQiTa(String str) {
        if (str.equals("刷新") || str.equals("退格"))
            return true;
        return false;
    }
    
    public void actionPerformed(ActionEvent e){  //事件处理
        String strCommand = e.getActionCommand();
        if (!isQiTa(strCommand)&&!strCommand.equals("=")) {
            str += strCommand;
            jtf.setText(str);
        }
        if (strCommand == "退格") {
            if (str == "")
                jtf.setText("到头了，你还退什么退啊");
            else {
                if (str.length() == 1){
                    str ="";
                    jtf.setText(str);
                }
                else {
                    str = str.substring(0, str.length() - 1);
                    jtf.setText(str);
                }
            }
        } else if (strCommand == "刷新") {
            str="";
            jtf.setText(str);
        }else if(strCommand.equals("=")){
            str+="=";
            /////////////////////////////////
            float f=new DealwithString().dealwithString(str); //调用
            /////////////////////////////////
            str+=f;
            jtf.setText(str);
        }
    }
    
    public static void main(String args[]){
        new Calculator();
    }

}