Mouse listener and motion event explorer

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Locale;

public class Main {

javax.swing supplies buttons, labels, panels and frames. java.awt supplies layouts, colours and fonts. java.awt.event supplies listener/event types. Locale is available where text formatting needs it. Main matches the source filename.

    static JPanel root(String title) {
        for(String key:new String[]{"Label.font","Button.font","RadioButton.font","CheckBox.font","TextField.font","TextArea.font","ComboBox.font"})UIManager.put(key,new Font(Font.SANS_SERIF,Font.PLAIN,18));

root configures the selected UIManager font keys to an 18-point sans-serif font before creating the form’s components. This affects the Java application, not the website’s CSS.

        JPanel panel=new JPanel(new BorderLayout(12,12));panel.setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
        JLabel heading=new JLabel(title);heading.setFont(new Font(Font.SANS_SERIF,Font.BOLD,24));panel.add(heading,BorderLayout.NORTH);return panel;
    }

BorderLayout places the heading in NORTH and leaves CENTER for each experiment’s form. The empty border adds padding; the heading uses a larger bold font. Return the JPanel for further assembly.

    static void show(String title,JPanel panel) {
        JFrame frame=new JFrame(title);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setContentPane(panel);frame.pack();frame.setLocationRelativeTo(null);frame.setVisible(true);
    }

show creates a JFrame, installs its content, packs it to component sizes, centres it and makes it visible. EXIT_ON_CLOSE ends this demonstration application when its window closes. The desktop main calls this helper on the event-dispatch thread.

    public static JPanel createPanel(){
        JPanel panel=root("Mouse Event Explorer");JLabel center=new JLabel("Move or click inside this area",SwingConstants.CENTER);center.setName("event");center.setPreferredSize(new Dimension(520,300));center.setBorder(BorderFactory.createLineBorder(new Color(110,130,150)));panel.add(center,BorderLayout.CENTER);

A named central JLabel provides a visible area with a preferred size and border. Mouse coordinates reported below are relative to the component receiving the event.

        MouseAdapter listener=new MouseAdapter(){
            void report(String name,MouseEvent e){center.setText(name+" at ("+e.getX()+", "+e.getY()+")");}

An anonymous MouseAdapter overrides only the callbacks needed by this exercise. report updates the central label with an event name and the event’s x/y coordinates.

            @Override public void mouseClicked(MouseEvent e){report("mouseClicked",e);}
            @Override public void mousePressed(MouseEvent e){report("mousePressed",e);}
            @Override public void mouseReleased(MouseEvent e){report("mouseReleased",e);}
            @Override public void mouseEntered(MouseEvent e){report("mouseEntered",e);}
            @Override public void mouseExited(MouseEvent e){report("mouseExited",e);}

Each override reports the matching callback: clicked, pressed, released, entered or exited. These are distinct events; one physical interaction can trigger several in sequence.

            @Override public void mouseMoved(MouseEvent e){report("mouseMoved",e);}
            @Override public void mouseDragged(MouseEvent e){report("mouseDragged",e);}
            @Override public void mouseWheelMoved(MouseWheelEvent e){center.setText("mouseWheelMoved: rotation "+e.getWheelRotation());}
        };

Moved and dragged use coordinate reports. The wheel callback displays wheel rotation rather than x/y. The closing brace/semicolon finishes the anonymous listener object.

        center.addMouseListener(listener);center.addMouseMotionListener(listener);center.addMouseWheelListener(listener);return panel;
    }

Mouse, motion and wheel events have separate registration methods. Registering only addMouseListener would not deliver mouseMoved or wheel callbacks. Return the panel after all registrations.

    public static void main(String[] args){SwingUtilities.invokeLater(()->show("Mouse Event Explorer",createPanel()));}

}

SwingUtilities.invokeLater schedules the lambda on Swing’s event-dispatch thread. The lambda creates the panel and calls show. This main needs a graphical desktop; the panel and its event handlers are separate from console input.