ボタンイベント

import java.awt.*;
import java.awt.event.*;

public class TestJavaApplication extends Frame implements ActionListener{
	Label l1;
	TextField t1;
	Button b1;
	
	public TestJavaApplication () {
		super();
		setSize(300,100);
		setLayout(null);
		l1 = new Label("please type number:");
		l1.setBounds(50,30,200,20);
		Font f1 = new Font("Dialog",Font.BOLD, 14);
		l1.setFont(f1);
		add(l1);
		t1 = new TextField("10");
		t1.setBounds(50,60,200,20);
		add(t1);
		b1 = new Button("OK");
		b1.setBounds(100,100,100,25);
		add(b1);
		b1.addActionListener(this);
	}
	
	public static void main(String args[]) {
		TestJavaApplication f = new TestJavaApplication();
		f.show();
	}
	
	public void actionPerformed(ActionEvent e) {
		String s = t1.getText();
		int n = Integer.parseInt(s);
		int m = 0;
		for (int i = 1; i <= n; i++)
			m += i;
		s = Integer.toString(m);
		l1.setText("total: " + s);
	}
	
}