Contoh program yang menggunakan GUI (Graphical User Interface) dengan notepad++

Di sini saya membuat program menentukan luas persegi panjang, dan hasil outputnya adalah :

Untuk source code nya:

import javax.swing.*;

import java.awt.event.*;

public class jframe extends JFrame{

public jframe(){

initComponents();

}

private void initComponents(){

setTitle("LUAS PERSEGI PANJANG");

setSize(550, 400);

setDefaultCloseOperation(EXIT_ON_CLOSE);

panel = new JPanel();

namaLabel = new JLabel("Nama");

nimLabel = new JLabel("Nim");

aLabel = new JLabel("Menghitung Luas Persegi Panjang:");

panjangLabel = new JLabel("Panjang");

lebarLabel = new JLabel("Lebar");

luasLabel = new JLabel("Luas ");

namaTextField= new JTextField();

nimTextField= new JTextField();

aTextField= new JTextField();

panjangTextField = new JTextField();

lebarTextField = new JTextField();

luasTextField = new JTextField();

hitungButton = new JButton("Hitung");

tutupButton = new JButton("Tutup");

panel.setLayout(null);

getContentPane().add(panel);

panel.add(namaLabel);

panel.add(nimLabel);

panel.add(aLabel);

panel.add(panjangLabel);

panel.add(lebarLabel);

panel.add(luasLabel);

panel.add(namaTextField);

panel.add(nimTextField);

panel.add(panjangTextField);

panel.add(lebarTextField);

panel.add(luasTextField);

panel.add(hitungButton);

panel.add(tutupButton);

namaLabel.setBounds(30,30,90,25);

nimLabel.setBounds(30,60,90,25);

aLabel.setBounds(30,90,900,25);

panjangLabel.setBounds(30,120,90,25);

lebarLabel.setBounds(30,150,90,25);

luasLabel.setBounds(30,180,90,25);

namaTextField.setBounds(100,30,400,25);

nimTextField.setBounds(100,60,400,25);

panjangTextField.setBounds(100,120,400,25);

lebarTextField.setBounds(100,150,400,25);

luasTextField.setBounds(100,180,400,25);

hitungButton.setBounds(200,230,90,30);

tutupButton.setBounds(350,230,90,30);

luasTextField.setEditable(false);

hitungButton.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent evt){

hitungButtonActionPerformed(evt);

}

});

tutupButton.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent evt){

tutupButtonActionPerformed(evt);

}

});

}

private void hitungButtonActionPerformed(ActionEvent evt){

double panjang=0, lebar=0, luas;

try{

panjang=Double.parseDouble(panjangTextField.getText());

}catch (NumberFormatException ex){

JOptionPane.showMessageDialog(this, "Yang anda masukan salah !!");

}

try{

lebar= Double.parseDouble(lebarTextField.getText());

} catch (NumberFormatException ex){

JOptionPane.showMessageDialog(this, "Yang anda masukan salah !!");

}

luas = (panjang) * (lebar);

luasTextField.setText(Double.toString(luas));

}

private void tutupButtonActionPerformed(ActionEvent evt){

System.exit(0);

}

public static void main(String[] args){

new jframe().setVisible(true);

}

private JPanel panel;

private JLabel namaLabel;

private JLabel nimLabel;

private JLabel aLabel;

private JLabel panjangLabel;

private JLabel lebarLabel;

private JLabel luasLabel;

private JTextField namaTextField;

private JTextField nimTextField;

private JTextField aTextField;

private JTextField panjangTextField;

private JTextField lebarTextField;

private JTextField luasTextField;

private JButton hitungButton;

private JButton tutupButton;

}