computer.java

基础性的JAVA源代码

package exec.day1009;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
 * 实现连加操作
 * @author new
 *
 */
public class Computer extends JFrame{
	private  JTextField tf;
	private JPanel panel;
	private Font font;
	private JButton buttons[];
	public Computer(){
		this.init();
		this.eventHandle();
		this.showMe();
	}
	public void init(){
		tf = new JTextField();
		panel = new JPanel();
		panel.setLayout(new GridLayout(4,5));
		font = new Font("Courier",Font.PLAIN,20);
		tf.setFont(font);
		this.add(tf,"North");
		String[] data = {"7","8","9","/","sqrt","4","5","6",
				"*","%","1","2","3","-","1/x","0","+/-",".","+",
				"="};
		buttons = new JButton[data.length];
		for(int i=0;i<data.length;i++){
			buttons[i] = new JButton(data[i]);
			buttons[i].setFont(font);
			panel.add(buttons[i]);
		}
		add(panel);
	}
	
	public void eventHandle(){
		addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e){
				System.exit(0);
			}
		});
		Monitor  m = new Monitor();
		for(int i=0;i<buttons.length;i++){
			buttons[i].addActionListener(m);  //ActionEvent
		}
	}
	
	public void showMe(){
		setSize(350,300);
		setVisible(true);
	}
	
	public static void main(String[] args){
		new Computer();
	}
	
	class Monitor implements  ActionListener{
		boolean flag = true;
		String first = "0";		
		
		public void actionPerformed(ActionEvent e){
			String command = e.getActionCommand();
			String old = tf.getText();
			if(command.equals("1")||command.equals("2")||
					command.equals("3")||command.equals("4")||
					command.equals("5")||command.equals("6")||
					command.equals("7")||command.equals("8")||
					command.equals("9")||command.equals("0")){
				if(flag){
					tf.setText(old+command); 
				}else{
					tf.setText(command);
					flag = true;
				}
			}
			if(command.equals("+")){		
				int one = Integer.parseInt(first);
				int two = Integer.parseInt(old);
				int result = one + two;
				tf.setText(result+"");

				flag = false;
				first = result+"";   
			}
			if(command.equals("=")){
				int one = Integer.parseInt(first);
				int two = Integer.parseInt(old);
				int result = one + two;
				tf.setText(result+"");
				first = "0";   
			}
			if(command.equals("sqrt")){
				tf.setText(Math.sqrt(Double.parseDouble(old))+"");
			}			
		}
	}
}