////////////////////////////////////////////////////////
// CONSTRUCTOR FOR GUI
////////////////////////////////////////////////////////
public MoveABall() {
// Set up a panel for the buttons
JPanel btnPanel = new JPanel(new FlowLayout()); // automatically centers and wraps components
// Set up a custom drawing JPanel
canvas = new DrawCanvas();
canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT));
// Add both panels to this JFrame
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
cp.add(canvas, BorderLayout.CENTER);
cp.add(btnPanel, BorderLayout.SOUTH);
// Add Components to btnPanel
JButton btnUp = new JButton("Move Up ");
btnPanel.add(btnUp);
btnUp.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
y -= 10;
canvas.repaint();
requestFocus(); // change the focus to JFrame to receive KeyEvent
}
});
JButton btnLeft = new JButton("Move Left ");
btnPanel.add(btnLeft);
btnLeft.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
x -= 10;
canvas.repaint();
requestFocus(); // change the focus to JFrame to receive KeyEvent
}
});
JButton btnRight = new JButton("Move Right");
btnPanel.add(btnRight);
btnRight.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
x += 10;
canvas.repaint();
requestFocus(); // change the focus to JFrame to receive KeyEvent
}
});
JButton btnDown = new JButton("Move Down");
btnPanel.add(btnDown);
btnDown.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
y += 10;
canvas.repaint();
requestFocus(); // change the focus to JFrame to receive KeyEvent
}
});
// "this" JFrame fires KeyEvent
addKeyListener(
new KeyAdapter() {
@Override
public void keyPressed(KeyEvent evt) {
switch (evt.getKeyCode()) {
case KeyEvent.VK_LEFT:
x -= 10;
repaint();
break;
case KeyEvent.VK_RIGHT:
x += 10;
repaint();
break;
case KeyEvent.VK_UP:
y -= 10;
repaint();
break;
case KeyEvent.VK_DOWN:
y += 10;
repaint();
break;
case KeyEvent.VK_A:
x -= 10;
repaint();
break;
case KeyEvent.VK_D:
x += 10;
repaint();
break;
case KeyEvent.VK_W:
y -= 10;
repaint();
break;
case KeyEvent.VK_S:
y += 10;
repaint();
break;
}
}
});
// Setup the Frame the way we want it
setTitle("Move a Ball");
pack(); // automagically resize the frame to fit the components
setVisible(true); // this line is always after adding components
requestFocus(); // set the focus to JFrame to receive KeyEvent
} // end constructor