Question

As a contrast to this wiki, I am looking for the proper way to implement Swing GUI controls from a coding standpoint.

I have been on a quest to learn Java and its GUI tools but I find internet tutorial after internet tutorial that throws everything in main and I know this isn’t right.

I’ve also tried RAD systems like Netbeans and other “visual” editors but by the time I get to coding I’ve got a heap of code that I don’t know half of what it does, so I’m intent on learning to hand code swing, and I know the basic controls and layout, but want to do it the right way.

Is there a model or standard I’m missing?

example questions…

do I extend JFrame and create my own frame object? (I would assume yes)

do I encapsulate the main menu inside that frame object? or do I create its own? etc…

How to I separate “View” logic from “Application” logic?

Basically, I’m looking for what the industry standard is, on how to organize GUI code.

Answer 1

Since there seems to be some argument about what constitutes “best practices”, I’ll give you what I have found works best for me, and my reasoning:

1.
Each window should extend either JFrame or JDialog (depending on the type of window). This makes it easy to control the properties of the window without specifying a specific object every time. This is more of the general case, though, as I have been known to do it both ways.

2.
The main() method should be in a separate class. This increases the likelihood of being able to use your window classes elsewhere, as they are not tied to specific implementations. Technically it doesn’t make a difference, but application startup code just doesn’t belong in a window.

3.
Listeners should be in anonymous inner classes. Your top-level class should not implement any listeners. This prevents hacks like calling the listener methods from anywhere except the object to which they are attached.

Here is a simple application with a single frame to demonstrate these practices:

public class Main {
    public static void main(String[] args) {
        final String text = args[0];
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                final MyWindow wnd = new MyWindow(text);
                wnd.setVisible(true);
            }
        });
    }
}

public class MyWindow extends JFrame {
    public MyWindow(String text) {
        super("My Window");

        setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                MyWindow.this.setVisible(false);
                MyWindow.this.dispose();
            }
        });

        final JButton btn = new JButton(text);
        btn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JOptionPane.showMessageDialog(MyWindow.this, "Button Pressed", "Hey", JOptionPane.INFORMATION_MESSAGE);
            }
        });

        setLayout(new FlowLayout());
        add(btn);
        pack();
    }
}