我是 Java 图形新手，所以大部分代码都是我从互联网上收集的东西并将其注入到我自己的程序中。该程序的目的是有一个由箭头键控制的红色方块，检测它何时与下落的蓝点碰撞，每次碰到底部时蓝点都会重置到顶部。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Surface extends JPanel implements ActionListener, KeyListener {
private final int DELAY = 8;
private Timer timer;
private Image image;
private int x, y;
private final int MOVE_AMOUNT = 5;
public final int width = 800;
public final int length = 600;
private boolean upPressed, downPressed, leftPressed, rightPressed;
;
public Surface() {
setDoubleBuffered(true);
initTimer();
loadImage();
setFocusable(true);
requestFocusInWindow();
addKeyListener(this);
x = 200;
y = 200;
}
private Image resizeImage(Image originalImage, int newWidth, int newHeight) {
return originalImage.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH);
}
public Rectangle getRedDotBounds() {
return new Rectangle(x, y, image.getWidth(this), image.getHeight(this));
}
private void initTimer() {
timer = new Timer(DELAY, this);
timer.start();
}
private void loadImage(){
ImageIcon ii = new ImageIcon("Basic_red_dot.png");
if (ii.getImageLoadStatus() == MediaTracker.ERRORED) {
System.out.println("Image failed to load.");
}
Image originalImage =ii.getImage();
// Resize the image to the desired dimensions
int newWidth = 75; // Set the desired width
int newHeight = 75; // Set the desired height
image = resizeImage(originalImage, newWidth, newHeight);
}
@Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
g.clearRect(0, 0, getWidth(), getHeight());
drawImage(g);
}
private void drawImage(Graphics g){
g.drawImage(image, x, y, this);
}
public Timer getTimer() {
return timer;
}
public void actionPerformed(ActionEvent e) {
updatePosition();
repaint();
}
private void updatePosition(){
if (leftPressed){
x = Math.max(x-MOVE_AMOUNT, 0);
}
if(rightPressed){
x = Math.min(x + MOVE_AMOUNT, getWidth() - image.getWidth(this));
}
if(upPressed){
y = Math.max(y - MOVE_AMOUNT, 0);
}
if(downPressed){
y = Math.min(y + MOVE_AMOUNT, getHeight() - image.getHeight(this));
}
}
@Override
public void keyPressed(KeyEvent e){
int key = e.getKeyCode();
switch (key) {
case KeyEvent.VK_LEFT:
leftPressed = true;
break;
case KeyEvent.VK_RIGHT:
rightPressed = true;
break;
case KeyEvent.VK_UP:
upPressed = true;
break;
case KeyEvent.VK_DOWN:
downPressed = true;
break;
}
repaint();
}
@Override
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
switch (key) {
case KeyEvent.VK_LEFT:
leftPressed = false;
break;
case KeyEvent.VK_RIGHT:
rightPressed = false;
break;
case KeyEvent.VK_UP:
upPressed = false;
break;
case KeyEvent.VK_DOWN:
downPressed = false;
break;
}
}
@Override
public void keyTyped(KeyEvent e) {
// Not used, but required by KeyListener
}
}
class BlueDot extends JPanel implements ActionListener {
private int x, y;
private Image image;
private final int DOT_SIZE = 10;
private final int FALL_SPEED = 1;
private Timer timer;
private int n = 0;
public BlueDot() {
setDoubleBuffered(true);
setPreferredSize(new Dimension(500, 500));
x = (int) (Math.random()*500);
y = 0;
loadImage();
timer = new Timer(10, this);
timer.start();
}
private Image resizeImage(Image originalImage, int newWidth, int newHeight) {
return originalImage.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH);
}
private void loadImage() {
ImageIcon ii = new ImageIcon("Basic_blue_dot.png");
if (ii.getImageLoadStatus() == MediaTracker.ERRORED) {
System.out.println("Image failed to load.");
}
Image originalImage =ii.getImage();
// Resize the image to the desired dimensions
int newWidth = 200; // Set the desired width
int newHeight = 200; // Set the desired height
image = resizeImage(originalImage, newWidth, newHeight);
}
public Rectangle getBlueDotBounds() {
return new Rectangle(x, y, DOT_SIZE, DOT_SIZE);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.clearRect(0, 0, getWidth(), getHeight());
g.drawImage(image, x, y, DOT_SIZE, DOT_SIZE, this);
}
public void actionPerformed(ActionEvent e){
y += FALL_SPEED;
if (y > getHeight()) {
n++;
System.out.println("reset" + n);
x = (int) (Math.random() * 500);
y = 0;
}
//repaint();
}
}
public class MyProgram
{
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JFrame frame = new JFrame();
frame.setTitle("Image Display");
frame.setSize(500,500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Surface surface = new Surface();
BlueDot blueDot = new BlueDot();
frame.setLayout(null);
surface.setBounds(0, 0, 500, 500);
frame.add(surface);
blueDot.setBounds((int) (Math.random() * 450), 0, 500, 500);
frame.add(blueDot);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
surface.requestFocusInWindow();
frame.addWindowListener(new WindowAdapter() {
@Override
public void windowOpened(WindowEvent e) {
surface.requestFocusInWindow();
}
});
Timer collisionTimer = new Timer(10, new ActionListener() {
public void actionPerformed(ActionEvent e) {
Rectangle redBounds = surface.getRedDotBounds();
Rectangle blueBounds = blueDot.getBlueDotBounds();
if (redBounds.intersects(blueBounds)) {
System.out.println("Collision!!!!");
}
}
});
collisionTimer.start();
}
});
}
}
碰撞检测有点偏差，主要是红方块和蓝点不断闪烁。我尝试注释掉三个重绘语句中的每一个，但这要么导致两个元素之一不可见，要么导致其他一些明显的问题。我怎样才能修复程序，使闪烁消失并且碰撞检测完美地工作？
尝试使用 BufferedImage 而不是 Image，就像在这个问题的代码中一样：display-moving-image-in-java-swing