caculator.java

Java计算器

import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 
/** 
* @author 李政劭 
* 一个简单地计算器 
*/ 
public class Caculator extends JPanel
{ 
	private static final long serialVersionUID = 1L; 
	private JButton buttonDvision,buttonPlus,buttonMinus; 
	private JButton buttonD,buttonEqual,buttonNC,buttonMupl; 
	private JButton[] buttons = new JButton[10]; 
	private JTextField field; 
	private String x = "0"; 
	private String y = "0"; 
	private String numbers = ""; 
	private String symbol; 
	private double answer = 0; 
	private boolean exist = false; 

	public static void main(String args[])
	{ 
		GUI(); 
	} 

	public static void GUI()
	{ 
		JFrame frame = new JFrame("caculator"); 
		frame.setContentPane(new Caculator()); 
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
		frame.pack(); 
		frame.setVisible(true); 

	} 

	public Caculator()
	{ 
		JPanel panelLeft = new JPanel(); 
		JPanel panelRight = new JPanel(); 
		JPanel panelUp = new JPanel(); 

		for(int i = 9 ; i >= 0 ; i--)
		{ 
			int j = i; 
			if(i % 3 == 0 && i >= 3)
			{ 
				j = j - 2; 
			} 

			if((i + 2) % 3 == 0 )
			{ 
				j =j + 2; 
			} 

			buttons[i] = new JButton("" + j); 
			panelLeft.add(buttons[i]); 
		} 

		panelLeft.setLayout(new GridLayout(4, 3)); 
		panelRight.setLayout(new GridLayout(4, 1)); 

		buttonD = new JButton("."); 
		buttonEqual = new JButton("="); 
		buttonPlus = new JButton("+"); 
		buttonMinus = new JButton("-"); 
		buttonMupl = new JButton("*"); 
		buttonDvision = new JButton("%"); 
		buttonNC = new JButton("NC"); 
		field = new JTextField("0.0",14); 
		field.setVisible(true); 
		field.setEditable(false); 

		for(int i = 0 ; i < 10 ; i++)
		{ 
			buttons[i].addActionListener(new ListenerNumber()); 
		} 

		buttonD.addActionListener(new ListenerD()); 
		buttonEqual.addActionListener(new ListenerEqual()); 
		buttonPlus.addActionListener(new ListenerSymbol()); 
		buttonMinus.addActionListener(new ListenerSymbol()); 
		buttonMupl.addActionListener(new ListenerSymbol()); 
		buttonDvision.addActionListener(new ListenerSymbol()); 
		buttonNC.addActionListener(new ListenerNC()); 

		panelLeft.add(buttonD); 
		panelLeft.add(buttonEqual); 
		panelRight.add(buttonPlus); 
		panelRight.add(buttonMinus); 
		panelRight.add(buttonMupl); 
		panelRight.add(buttonDvision); 
		panelUp.add(field); 
		panelUp.add(buttonNC); 

		setLayout(new BorderLayout()); 
		add(panelLeft,BorderLayout.CENTER); 
		add(panelRight,BorderLayout.EAST); 
		add(panelUp,BorderLayout.NORTH); 

	} 

	class ListenerNumber implements ActionListener 
	{ 
		public void actionPerformed(ActionEvent event) 
		{ 
			if(event.getSource() instanceof JButton)
			{ 
				JButton actButton = (JButton)(event.getSource()); 
				numbers = numbers + actButton.getText(); 
				field.setText(numbers); 
			} 
		} 
	} 

	class ListenerD implements ActionListener 
	{ 
		public void actionPerformed(ActionEvent event) 
		{ 
			if(exist == false && numbers != "")
			{ 
				numbers+="."; 
				field.setText(numbers); 
				exist = true; 
			} 
		} 
	} 

	class ListenerSymbol implements ActionListener 
	{ 
		public void actionPerformed(ActionEvent event)
	 	{ 
			if(event.getSource() instanceof JButton)
			{ 
				JButton actButton = (JButton)(event.getSource()); 
				symbol = actButton.getText(); 
				x = field.getText(); 
				field.setText(""); 
				numbers = ""; 
			} 
		} 
	} 

	class ListenerEqual implements ActionListener 
	{ 
			public void actionPerformed(ActionEvent event) 
			{ 
				try
				{ 
					double a; 
					double b; 
					y = field.getText(); 
					a = Double.parseDouble(x); 
					b = Double.parseDouble(y); 
				
					if(symbol == "+")
					{ 
						answer = a + b; 
					}
					else if(symbol == "-")
					{ 
						answer = a - b; 
					}
					else if(symbol == "*")
					{ 
						answer = a * b; 
					}
					else if(symbol == "%")
					{ 
						answer = a / b; 
					}
					else
					{ 
						answer = b; 
					} 
					field.setText("" + answer); 
					exist = false; 
					numbers = ""; 
					answer = 0; 
					symbol = ""; 
					x = "0"; 
					y = "0"; 
				}	
				catch(NumberFormatException e )
				{ 
					exist = false; 
					numbers = ""; 
					field.setText("0.0"); 
					answer = 0; 
					symbol = ""; 
					x = "0"; 
					y = "0"; 
				} 
			} 
	} 

	class ListenerNC implements ActionListener 
	{ 
		public void actionPerformed(ActionEvent event) 
		{ 
			symbol = ""; 
			x = "0"; 
			y = "0"; 
			exist = false; 
			numbers = ""; 
			field.setText("0.0"); 
		} 
	} 
}