在我尝试制作的游戏中，直到我移动角色，图像才开始绘制。
这是我的代码：
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ForgottenMain extends JPanel implements KeyListener,MouseListener{
/**
*
*/
private static final int TIMER_DELAY = 35;
private static final long serialVersionUID = -4926251405849574401L;
public static BufferedImage attic,flashlight,player,killer;
public static boolean up,down,left,right,inAttic;
public static int px,py,kx,ky;
public static int spawnLocation;
public static JFrame frame = new JFrame("Forgotten");
public static void main(String[] args){
inAttic = true;
px = 600;
py = 400;
frame.setSize(1200,800);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
frame.add(new ForgottenMain());
}
public ForgottenMain(){
init();
}
public void init(){
setSize(1200,800);
setVisible(true);
frame.addKeyListener(this);
frame.addMouseListener(this);
try{
player = ImageIO.read(new File("char.png"));
flashlight = ImageIO.read(new File("flashlightimage.png"));
attic = ImageIO.read(new File("attic.png"));
killer = ImageIO.read(new File("killer.png"));
} catch (Exception e){
e.printStackTrace();
}
// Gameloop
new javax.swing.Timer(TIMER_DELAY, new ActionListener() {
public void actionPerformed(ActionEvent e) {
gameLoop();
}
}).start();
}
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D) g;
int fx = px - 1033;
int fy = py - 635;
kx = 500;
ky = 500;
// Removes the flickering of the images
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// Resets the screen to make sure that it only shows the character once
g2.clearRect(0, 0, 1200, 800);
// Draws the background attic
g2.drawImage(attic,0,0,this);
// Draws the player
g2.drawImage(player, px, py, this);
// Draws the Serial Killer
g2.drawImage(killer, kx, ky, this);
// Draws the flashlight
g2.drawImage(flashlight, fx, fy, this);
System.out.println(px + " " + py);
}
public void gameLoop(){
if(up == true && py > 88){
py-=4;
repaint();
}
if(down == true && py < 604){
py+=4;
repaint();
}
if(left == true && px > 80){
px-=4;
repaint();
}
if(right == true && px < 1028){
px+=4;
repaint();
}
}
@Override
public void mouseClicked(MouseEvent arg0) {
System.out.println("MouseLocation: " + arg0.getX() + ", " + arg0.getY());
}
@Override
public void mouseEntered(MouseEvent arg0) {
}
@Override
public void mouseExited(MouseEvent arg0) {
}
@Override
public void mousePressed(MouseEvent arg0) {
}
@Override
public void mouseReleased(MouseEvent arg0) {
}
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == 87){
up = true;
}
if(e.getKeyCode() == 83){
down = true;
}
if(e.getKeyCode() == 65){
left = true;
}
if(e.getKeyCode() == 68){
right = true;
}
}
@Override
public void keyReleased(KeyEvent e) {
if(e.getKeyCode() == 87){
up = false;
}
if(e.getKeyCode() == 83){
down = false;
}
if(e.getKeyCode() == 65){
left = false;
}
if(e.getKeyCode() == 68){
right = false;
}
}
@Override
public void keyTyped(KeyEvent e) {
}
}
例如，在我的游戏中，您用W，A，S和D键移动了角色。程序运行时，它将显示一个空白屏幕，并且没有显示所有应绘制的内容，直到我按下W键， A，S或D。
如果我遗漏了什么，请告诉我。我以为可能是在初始化图像之前尝试绘制，所以我在初始化图像后进行了重新绘制，但没有帮助。
最佳答案
问题在于，由于boolean值up，down，left或right都不是true，因此gameLoop()中的逻辑将不要求repaint()！可以通过从repaint()方法显式调用main(String[])来解决此问题。
public static void main(String[] args) {
inAttic = true;
px = 600;
py = 400;
//frame.setSize(1200, 800);
ForgottenMain fm = new ForgottenMain();
frame.add(fm);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
fm.repaint();
}
其他提示：
错误的方法：
public void paint(Graphics g){ ..应该是public void paintComponent(Graphics g){ super.paintComponent(g); ..（调用super方法也很重要）。frame.setSize(1200,800); .. setSize(1200,800);这是错误的，由于边框装饰，面板的尺寸将小于1200 x 800，并且布局管理器通常会忽略超出首选尺寸的尺寸。要解决这个问题：绘画表面中的
@Override public Dimension getPreferredSize() { return new Dimension(1200,800); }（JPanel）。将面板添加到框架。
在添加组件并调用
frame.pack();之后但在frame.setResizable(false);之前调用frame.setVisible(true);。player = ImageIO.read(new File("char.png"));应用程序资源将在部署时成为嵌入式资源，因此明智的做法是立即开始访问它们。 embedded-resource必须通过URL而不是文件进行访问。有关如何形成URL，请参见info. page for embedded resource。if (e.getKeyCode() == 87) {请勿使用“幻数”，而应使用KeyEvent.VK_..。它不仅提供编译时间检查，而且还为其他程序员提供了更好的文档。关于java - 在我搬东西之前不画图，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/38538383/