Question

好的，我只是一个新手，我正在尝试各种代码。现在我发现这个游戏GUI src在文件夹中有一些图像文件，这是整个游戏工作的必要条件。我尝试了一些方法，但我无法理解如何将src连接到该文件夹。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。

我想要的是如何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，但它显示异常...... 我还不清楚吗？ ._。

好吧就是这样：

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);
        }
    }
}

这就是例外：

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.

Answer 1

你如何加载想象与包没有任何关系。

通常，您会通过类路径找到图像作为资源。这可以按照您的意愿安排。

我尝试了一些方法，但我无法理解如何将src连接到该文件夹。

通常您构建一个应用程序。当你运行它时，你使用构建，而不是src。即，在运行程序时不使用源代码。通常，图像将使用您在源中使用的相同路径进行复制，并且此相对路径是您用于查找和加载图像的路径。

我不能更具体，因为问题中没有足够的细节，例如您的目录结构是什么以及您正在使用哪个IDE或构建系统。

你如何使用包？

1 个答案: