好的，我只是这里的新手，我正在尝试一些不同的代码。现在我发现这个游戏 GUI src 在一个文件夹中有一些图像文件，这是整个游戏运行的必要条件。我尝试了一些方法，但我就是不明白如何使 src 连接到文件夹。该程序现在运行，但它只显示黑屏，因为它无法连接到图像。拜托，我需要帮助。
我只想让程序识别我正在使用的文件作为背景图像等。代码行在那里，但它显示一个异常......我还是不清楚吗？._.
好吧，它是这样的：
package moon_lander;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
* Actual game.
*
* @author www.gametutorial.net
*/
public class Game {
/**
* The space rocket with which player will have to land.
*/
private PlayerRocket playerRocket;
/**
* Landing area on which rocket will have to land.
*/
private LandingArea landingArea;
/**
* Game background image.
*/
private BufferedImage backgroundImg;
/**
* Red border of the frame. It is used when player crash the rocket.
*/
private BufferedImage redBorderImg;
public Game()
{
Framework.gameState = Framework.GameState.GAME_CONTENT_LOADING;
Thread threadForInitGame = new Thread() {
@Override
public void run(){
// Sets variables and objects for the game.
Initialize();
// Load game files (images, sounds, ...)
LoadContent();
Framework.gameState = Framework.GameState.PLAYING;
}
};
threadForInitGame.start();
}
/**
* Set variables and objects for the game.
*/
private void Initialize()
{
playerRocket = new PlayerRocket();
landingArea = new LandingArea();
}
/**
* Load game files - images, sounds, ...
*/
private void LoadContent()
{
try
{
URL backgroundImgUrl = this.getClass().getResource("/moon_lander/resources/images/background.jpg");
backgroundImg = ImageIO.read(backgroundImgUrl);
URL redBorderImgUrl = this.getClass().getResource("/moon_lander/resources/images/red_border.png");
redBorderImg = ImageIO.read(redBorderImgUrl);
}
catch (IOException ex) {
Logger.getLogger(Game.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Restart game - reset some variables.
*/
public void RestartGame()
{
playerRocket.ResetPlayer();
}
/**
* Update game logic.
*
* @param gameTime gameTime of the game.
* @param mousePosition current mouse position.
*/
public void UpdateGame(long gameTime, Point mousePosition)
{
// Move the rocket
playerRocket.Update();
// Checks where the player rocket is. Is it still in the space or is it landed or crashed?
// First we check bottom y coordinate of the rocket if is it near the landing area.
if(playerRocket.y + playerRocket.rocketImgHeight - 10 > landingArea.y)
{
// Here we check if the rocket is over landing area.
if((playerRocket.x > landingArea.x) && (playerRocket.x < landingArea.x + landingArea.landingAreaImgWidth - playerRocket.rocketImgWidth))
{
// Here we check if the rocket speed isn't too high.
if(playerRocket.speedY <= playerRocket.topLandingSpeed)
playerRocket.landed = true;
else
playerRocket.crashed = true;
}
else
playerRocket.crashed = true;
Framework.gameState = Framework.GameState.GAMEOVER;
}
}
/**
* Draw the game to the screen.
*
* @param g2d Graphics2D
* @param mousePosition current mouse position.
*/
public void Draw(Graphics2D g2d, Point mousePosition)
{
g2d.drawImage(backgroundImg, 0, 0, Framework.frameWidth, Framework.frameHeight, null);
landingArea.Draw(g2d);
playerRocket.Draw(g2d);
}
/**
* Draw the game over screen.
*
* @param g2d Graphics2D
* @param mousePosition Current mouse position.
* @param gameTime Game time in nanoseconds.
*/
public void DrawGameOver(Graphics2D g2d, Point mousePosition, long gameTime)
{
Draw(g2d, mousePosition);
g2d.drawString("Press space or enter to restart.", Framework.frameWidth / 2 - 100, Framework.frameHeight / 3 + 70);
if(playerRocket.landed)
{
g2d.drawString("You have successfully landed!", Framework.frameWidth / 2 - 100, Framework.frameHeight / 3);
g2d.drawString("You have landed in " + gameTime / Framework.secInNanosec + " seconds.", Framework.frameWidth / 2 - 100, Framework.frameHeight / 3 + 20);
}
else
{
g2d.setColor(Color.red);
g2d.drawString("You have crashed the rocket!", Framework.frameWidth / 2 - 95, Framework.frameHeight / 3);
g2d.drawImage(redBorderImg, 0, 0, Framework.frameWidth, Framework.frameHeight, null);
}
}
}
这是例外：
Exception in thread "Thread-2" java.lang.IllegalArgumentException: input == null!
at javax.imageio.ImageIO.read(ImageIO.java:1362)
at moon_lander.Framework.LoadContent(Framework.java:115)
at moon_lander.Framework.GameLoop(Framework.java:162)
at moon_lander.Framework.access$000(Framework.java:21)
at moon_lander.Framework$1.run(Framework.java:90)
Process completed.