자바 스윙(Java Swing)을 활용한 간단한 계산기

 

import java.awt.FlowLayout ;

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

import java.awt.event.ActionEvent ;
import java.awt.event.ActionListener ;

public class SwingCalc1st extends JFrame implements ActionListener {

	private JLabel labelPlus ;
	private JLabel labelEqual ;

	private JTextField textFieldLeftNum ;
	private JTextField textFieldRightNum ;
	private JTextField textFieldResult ;

	private JButton btn ; 

	SwingCalc1st() {
		super() ;

		labelPlus = new JLabel(" + ") ;
		labelEqual = new JLabel(" = ") ;

		textFieldLeftNum = new JTextField("", 8) ;
		textFieldRightNum = new JTextField("", 8) ;
		textFieldResult = new JTextField("", 12) ;

		btn = new JButton("계산하기") ;

		this.setLayout( new FlowLayout() ) ;

		this.add(textFieldLeftNum) ;
		this.add(labelPlus) ;

		this.add(textFieldRightNum) ;
		this.add(labelEqual) ;			

		this.add(textFieldResult) ;
		this.add(btn) ;

		textFieldLeftNum.setHorizontalAlignment(JTextField.RIGHT) ;
		textFieldRightNum.setHorizontalAlignment(JTextField.RIGHT) ;
		textFieldResult.setHorizontalAlignment(JTextField.RIGHT) ;

		btn.addActionListener(this) ;
	
		this.setTitle("간단한 스윙 계산기") ;
		this.setSize(500, 70) ;

		this.setLocation(200, 200) ;
		this.setVisible(true) ;

		this.setDefaultCloseOperation(EXIT_ON_CLOSE) ;
	}

	public static void main(String[] args)	 {
		SwingCalc1st sc1 = new SwingCalc1st() ;
	}

	public void actionPerformed(ActionEvent ae) {
		double result = Double.parseDouble(textFieldLeftNum.getText()) + 
                                Double.parseDouble(textFieldRightNum.getText()) ;

		textFieldResult.setText( Double.toString(result) ) ;
	}
}