import java.awt.*;

import java.awt.event.*;

import java.net.*;

import java.net.*;

import javax.imageio.ImageIO;

import javax.swing.*;

public class MotionWithKeyBindings

{

private JComponent component;

public MotionWithKeyBindings(JComponent component)

{

this.component = component;

}

// Move the component to its new location. The component will stop

// moving when it reaches the bounds of its container

public void move(int deltaX, int deltaY)

{

int componentWidth = component.getSize().width;

int componentHeight = component.getSize().height;

Dimension parentSize = component.getParent().getSize();

int parentWidth = parentSize.width;

int parentHeight = parentSize.height;

// Determine next X position

int nextX = Math.max(component.getLocation().x + deltaX, 0);

if ( nextX + componentWidth > parentWidth)

{

nextX = parentWidth - componentWidth;

}

// Determine next Y position

int nextY = Math.max(component.getLocation().y + deltaY, 0);

if ( nextY + componentHeight > parentHeight)

{

nextY = parentHeight - componentHeight;

}

// Move the component

component.setLocation(nextX, nextY);

}

public MotionAction addAction(String name, int deltaX, int deltaY)

{

MotionAction action = new MotionAction(name, deltaX, deltaY);

KeyStroke pressedKeyStroke = KeyStroke.getKeyStroke(name);

InputMap inputMap = component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);

inputMap.put(pressedKeyStroke, name);

component.getActionMap().put(name, action);

return action;

}

private class MotionAction extends AbstractAction

{

private int deltaX;

private int deltaY;

public MotionAction(String name, int deltaX, int deltaY)

{

super(name);

putValue(Action.ACTION_COMMAND_KEY, name);

this.deltaX = deltaX;

this.deltaY = deltaY;

}

public void actionPerformed(ActionEvent e)

{

move(deltaX, deltaY);

}

}

private static JButton addMotionSupport(JComponent component)

{

int delta = 3;

MotionWithKeyBindings motion = new MotionWithKeyBindings(component);

motion.addAction("LEFT", -delta, 0);

motion.addAction("RIGHT", delta, 0);

motion.addAction("UP", 0, -delta);

motion.addAction("DOWN", 0, delta);

Action left = component.getActionMap().get("LEFT");

return new JButton(left);

}

public static void main(String[] args)

{

EventQueue.invokeLater(new Runnable()

{

public void run()

{

// Create a panel with a component to be moved

JPanel content = new JPanel();

content.setLayout(null);

JLabel component = new JLabel( new ColorIcon(Color.BLUE, 40, 40) );

component.setSize( component.getPreferredSize() );

component.setLocation(100, 100);

content.add(component);

JButton left = addMotionSupport( component );

JFrame.setDefaultLookAndFeelDecorated(true);

JFrame frame = new JFrame("Motion With Key Bindings");

frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

frame.add( content );

frame.add(left, BorderLayout.PAGE_END);

frame.setSize(600, 600);

frame.setLocationByPlatform( true );

frame.setVisible(true);

}

});

}

static class ColorIcon implements Icon

{

private Color color;

private int width;

private int height;

public ColorIcon(Color color, int width, int height)

{

this.color = color;

this.width = width;

this.height = height;

}

public int getIconWidth()

{

return width;

}

public int getIconHeight()

{

return height;

}

public void paintIcon(Component c, Graphics g, int x, int y)

{

g.setColor(color);

g.fillRect(x, y, width, height);

}

}

}