これはアイデアの基本的な例です
基本的に、スペースバーを押すと、垂直方向の動きが生成され、エネルギーがなくなるまで時間が経つにつれて遅くなり、「バウンス」がなくなるまで落下して跳ね返ります。
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class JumpingSprite {
public static void main(String[] args) {
new JumpingSprite();
}
public JumpingSprite() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestPane extends JPanel {
protected static final int SPRITE_HEIGHT = 10;
protected static final int SPRITE_WIDTH = 10;
private float vDelta; // The vertical detla...
private float rbDelta; // Rebound delta...
private float rbDegDelta; // The amount the rebound is degregated...
private int yPos; // The vertical position...
private float gDelta; // Gravity, how much the vDelta will be reduced by over time...
private Timer engine;
private boolean bounce = false;
public TestPane() {
yPos = getPreferredSize().height - SPRITE_HEIGHT;
vDelta = 0;
gDelta = 0.25f;
// This is how much the re-bound will degrade on each cycle...
rbDegDelta = 2.5f;
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "jump");
am.put("jump", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
// Can only bound when we're actually on the ground...
// You might want to add fudge factor here so that the
// sprite can be within a given number of pixels in order to
// jump again...
if (yPos + SPRITE_HEIGHT == getHeight()) {
vDelta = -8;
rbDelta = vDelta;
bounce = true;
}
}
});
engine = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int height = getHeight();
// No point if we've not been sized...
if (height > 0) {
// Are we bouncing...
if (bounce) {
// Add the vDelta to the yPos
// vDelta may be postive or negative, allowing
// for both up and down movement...
yPos += vDelta;
// Add the gravity to the vDelta, this will slow down
// the upward movement and speed up the downward movement...
// You may wish to place a max speed to this
vDelta += gDelta;
// If the sprite is not on the ground...
if (yPos + SPRITE_HEIGHT >= height) {
// Seat the sprite on the ground
yPos = height - SPRITE_HEIGHT;
// If the re-bound delta is 0 or more then we've stopped
// bouncing...
if (rbDelta >= 0) {
// Stop bouncing...
bounce = false;
} else {
// Add the re-bound degregation delta to the re-bound delta
rbDelta += rbDegDelta;
// Set the vDelta...
vDelta = rbDelta;
}
}
}
}
repaint();
}
});
engine.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 1;
int xPos = (width - SPRITE_WIDTH) / 2;
g2d.drawOval(xPos, yPos, SPRITE_WIDTH, SPRITE_HEIGHT);
g2d.dispose();
}
}
}
この例では、 Key Bindings、Swing Timer、および基本的なカスタム ペイントの概念を紹介します