LibGDX - 控制台错误是什么意思，我该如何修复此控制台错误？

Question

下面是我得到的控制台错误：

Exception in thread "LWJGL Application" java.lang.NullPointerException
at com.dakotapederson.slingshotsteve.SlingshotSteve.render(SlingshotSteve.java:30)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:206)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114)

以下是代码：

package com.dakotapederson.slingshotsteve;

import com.badlogic.gdx.ApplicationListener;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureRegion;

public class SlingshotSteve implements ApplicationListener {
   // Creates our 2D images
   private SpriteBatch batch;
   private TextureRegion backgroundTexture;
   private Texture texture;


@Override
public void create() {


    Texture texture = new Texture(Gdx.files.internal("background.jpg"));
    backgroundTexture = new TextureRegion(texture, 20, 20, 50, 50);

}


@Override
public void render() {  
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.begin();
      batch.draw(backgroundTexture, 0, 0); 
      batch.end();

}

@Override
public void resize(int width, int height) {

}

@Override
public void pause() {

}

@Override
public void resume() {

}

@Override
public void dispose() {
       batch.dispose();
       texture.dispose();
}
}

控制台错误究竟意味着什么？因为如果他们在代码中出错，我需要知道它是什么。此外，由于我是新手，请尽可能清晰地描述代码中的错误。

Answer 1

您应该阅读基本教程：https://github.com/libgdx/libgdx/wiki/A-simple-game

你在create（）中缺少这一行：

batch = new SpriteBatch();