ChatGUIMockup - Java 8 - Swing

README.txt

To compile:

$ javac ChatGUIMockup.java

To run:

$ java ChatGUIMockup

ChatGUIMockup.java

import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class ChatGUIMockup extends JFrame {

    private JPanel panel;
    private JLabel chatLogLabel = null;
    private JTextArea chatLogTextArea = null;
    private JScrollPane chatLogScrollPane = null;
    private JLabel messageLabel = null;
    private JTextField messageTextField = null;
    private JButton sendButton = null;

    public static final Dimension WINDOW_SIZE = new Dimension(500, 300);

    public ChatGUIMockup() {
        // Basic window configuration:
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setPreferredSize(WINDOW_SIZE);
        this.setMinimumSize(WINDOW_SIZE);
        setUpGUI();
    }

    private static GridBagConstraints gbc() {
        return new GridBagConstraints();
    }

    private void setUpGUI() {
        panel = new JPanel();
        this.add(panel);
        GridBagLayout gridLayout = new GridBagLayout();
        panel.setLayout(gridLayout);

        GridBagConstraints con;

        {
            chatLogLabel = new JLabel("Chat log:");
            con = gbc();
            con.gridx = 0;
            con.gridy = 0;
            con.fill = GridBagConstraints.HORIZONTAL;
            con.anchor = GridBagConstraints.WEST;
            con.weighty = 0.05;
            panel.add(chatLogLabel, con);
        }

        {
            chatLogTextArea = new JTextArea();
            chatLogTextArea.setEditable(false);
            chatLogScrollPane = new JScrollPane(
                    chatLogTextArea,
                    JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
            con = gbc();
            con.gridx = 0;
            con.gridy = 1;
            con.gridwidth = 3;
            con.weighty = 0.9;
            con.weightx = 1.0;
            con.fill = GridBagConstraints.BOTH;
            con.anchor = GridBagConstraints.WEST;
            panel.add(chatLogScrollPane, con);
        }

        {
            messageLabel = new JLabel("Message:");
            con = gbc();
            con.gridx = 0;
            con.gridy = 2;
            con.weightx = 0.2;
            con.weighty = 0.05;
            con.anchor = GridBagConstraints.WEST;
            panel.add(messageLabel, con);
        }

        {
            messageTextField = new JTextField();
            con = gbc();
            con.gridx = 1;
            con.gridy = 2;
            con.weightx = 0.6;
            con.weighty = 0.05;
            con.ipadx = 200;
            con.anchor = GridBagConstraints.WEST;
            panel.add(messageTextField, con);
        }

        {
            sendButton = new JButton("Send");
            sendButton.addActionListener(e -> {
                String msg = messageTextField.getText();
                postMessage(msg);
            });
            con = gbc();
            con.gridx = 1;
            con.gridy = 2;
            con.weightx = 0.2;
            con.weighty = 0.05;
            con.anchor = GridBagConstraints.EAST;
            panel.add(sendButton, con);
        }
    }

    private void postMessage(String msg) {
        if (!msg.equals("")) {
            chatLogTextArea.append(String.format("Me: %s%n", msg));
            messageTextField.setText("");
            messageTextField.grabFocus();
        }
    }

    public void start() {
        this.pack();
        KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(e -> {
            if (e.getKeyCode() == KeyEvent.VK_ENTER) {
                if (messageTextField.hasFocus()) {
                    String msg = messageTextField.getText();
                    postMessage(msg);
                }
            }
            return false;
        });
        messageTextField.grabFocus();
        this.setVisible(true);
    }

    public static void main(String [] args) {
        ChatGUIMockup app = new ChatGUIMockup();
        app.start();
    }

}