calculator.java

一个关于公式分析得java小程序

package ddpie.expressionanalyze;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Calculator implements ActionListener{

	public static void main(String[] args) {
		Calculator cal = new Calculator();
		cal.setGUI();
	}
	public void setGUI(){
		frame.setLayout(new BorderLayout());
		//下面板
		frame.add(paneDn,BorderLayout.SOUTH);
		paneDn.setLayout(new BorderLayout());
		confirmBtn.setActionCommand("confirm");
		confirmBtn.addActionListener(this);
		cancelBtn.setActionCommand("reset");
		cancelBtn.addActionListener(this);
		paneDn.add(confirmBtn,BorderLayout.WEST);
		paneDn.add(cancelBtn,BorderLayout.EAST);
		//上面板
		frame.add(paneUp,BorderLayout.NORTH);
		paneUp.add(inTxt,BorderLayout.CENTER);
		//中面板
		frame.add(paneCtr,BorderLayout.CENTER);
		paneCtr.add(outTxt,BorderLayout.CENTER);
		paneCtr.add(new JScrollPane(outTxt));
		outTxt.setLineWrap(true);
		frame.addWindowListener(new WindowAdapter(){
				public void windowClosing(WindowEvent e){
					System.exit(0);	
				}
		});
		frame.setSize(300,200);
		frame.show();
	}
	public void actionPerformed(ActionEvent evt){
		if(evt.getActionCommand().equals("confirm")){
			try{
				ExpressionAnalyze expr = new ExpressionAnalyze(inTxt.getText());
				outTxt.setText(expr.getResult().toString());
			}
			catch(Exception e){
				outTxt.setText(e.toString());
			}
		}
		else if(evt.getActionCommand().equals("reset")){
			inTxt.setText("");
			outTxt.setText("");
		}
	}
	JFrame frame = new JFrame("Calculator");
	Panel paneDn = new Panel();
	JButton confirmBtn = new JButton("confirm");
	JButton cancelBtn = new JButton("reset");
	Panel paneUp = new Panel();
	JTextField inTxt = new JTextField(20);
	Panel paneCtr = new Panel();
	JTextArea outTxt = new JTextArea(5,20);
}