Đề 2 KMA

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

public class De2 extends Frame implements ActionListener {

    private Label lbForm, lbNguon, lbDich;
    private TextField tfNguon, tfDich;
    private Button btCopy, btHuy;
    private GridBagLayout gb;
    private GridBagConstraints gbc;

    public De2(String title) {
        super(title);
        this.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we) {
                System.exit(0);
            }
        });

        lbForm = new Label("Form Test");
        lbNguon = new Label("Source:");
        lbDich = new Label("Destination:");
        tfNguon = new TextField(20);
        tfDich = new TextField(20);
        btCopy = new Button("Copy to");
        btHuy = new Button("Cancel");

        gb = new GridBagLayout();
        this.setLayout(gb);

        this.Them(lbForm, 0, 0, 2, 1);
        this.Them(lbNguon, 0, 1, 1, 1);
        this.Them(lbDich, 0, 2, 1, 1);
        this.Them(tfNguon, 1, 1, 1, 1);
        this.Them(tfDich, 1, 2, 1, 1);
        this.Them(btCopy, 0, 3, 1, 1);
        this.Them(btHuy, 1, 3, 1, 1);

        btCopy.addActionListener(this);
        btHuy.addActionListener(this);
    }

    public void Them(Component comp, int x, int y, int rong, int cao) {
        gbc = new GridBagConstraints();
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.gridwidth = rong;
        gbc.gridheight = cao;
        gb.setConstraints(comp, gbc);
        this.add(comp);
    }

    public void actionPerformed(ActionEvent ae) {
        if (ae.getSource() == btCopy ) {
            String str = tfNguon.getText();
            if (str.isEmpty()) {
                System.out.println ("Loi roi");
            } else {
                tfDich.setText(str);
            }
        }
        if (ae.getSource() == btHuy) {
            tfNguon.getText();
            tfDich.getText();
            tfNguon.setText("");
            tfDich.setText("");
        }
    }

    public static void main(String[] args) {
        De2 fr = new De2("De 2 - Form Test");
        fr.setSize(300, 200);
        fr.setVisible(true);
    }
}