Andengine Demo Nullpointer

我想創建一個簡單的遊戲，我想使用andengine。Andengine Demo Nullpointer

所以我決定用這個代碼來測試庫：

public class PrisonBreakActivity extends BaseGameActivity { 

    private ZoomCamera mCamera; 
    private BitmapTextureAtlas mTexture; 
    private TextureRegion mFaceTextureRegion; 
    private Scene mScene; 

    private static final int CAMERA_WIDTH = 720; 
    private static final int CAMERA_HEIGHT = 480; 

    /** Called when the activity is first created. */ 

    @Override 
    public Engine onLoadEngine() { 
     // TODO Auto-generated method stub 
     return null; 
    } 

    @Override 
    public void onLoadResources() { 
     this.mTexture = new BitmapTextureAtlas(64, 64, TextureOptions.BILINEAR_PREMULTIPLYALPHA); 
     this.mFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(this.mTexture, this, "gfx/man.png", 0, 0); 

     this.mEngine.getTextureManager().loadTexture(this.mTexture); 

    } 

    @Override 
    public Scene onLoadScene() { 
     this.mEngine.registerUpdateHandler(new FPSLogger()); 

     this.mScene = new Scene(); 
     this.mScene.setBackground(new ColorBackground(0.09804f, 0.6274f, 0.8784f)); 

     this.mScene.setOnSceneTouchListener(new IOnSceneTouchListener() { 
       @Override 
       public boolean onSceneTouchEvent(Scene pScene, 
         TouchEvent pSceneTouchEvent) { 
        // TODO Auto-generated method stub 
        if(pSceneTouchEvent.isActionDown()) { 
         PrisonBreakActivity.this.loadNewTexture(); 
       } 

       return true; 
       } 
     }); 

     return this.mScene; 
    } 

    @Override 
    public void onLoadComplete() { 
     // TODO Auto-generated method stub 

    } 

    private void loadNewTexture() { 

     MathUtils mu = new MathUtils(); 

     //final TextureRegion faceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(this.mTexture, this, "gfx/man.png", 0, 0); 
     final float x = (CAMERA_WIDTH - mFaceTextureRegion.getWidth()) * mu.RANDOM.nextFloat(); 
     final float y = (CAMERA_HEIGHT - mFaceTextureRegion.getHeight()) * mu.RANDOM.nextFloat(); 
     final Sprite clickToUnload = new Sprite(x, y, mFaceTextureRegion); 
     this.mScene.attachChild(clickToUnload); 
} 
}

我得到百達在圖書館（BaseGameActivity）一個NullPointerException。 Image man.png位於/ asset/gfx /中。

GameBaseActivity (from Andengine, Error in applyEngineOptions): 

    @Override 
    protected void onCreate(final Bundle pSavedInstanceState) { 
     super.onCreate(pSavedInstanceState); 
     this.mPaused = true; 

     this.mEngine = this.onLoadEngine(); 

     this.applyEngineOptions(this.mEngine.getEngineOptions()); 

     this.onSetContentView(); 
    }

錯誤：

04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)

04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)

04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)

04-03 16:22:27.238: E/AndroidRuntime(425): at android.os.Handler.dispatchMessage(Handler.java:99) 04-03 16:22:27.238: E/AndroidRuntime(425): at android.os.Looper.loop(Looper.java:123) 04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread.main(ActivityThread.java:4627) 04-03 16:22:27.238: E/AndroidRuntime(425): at java.lang.reflect.Method.invokeNative(Native Method) 04-03 16:22:27.238: E/AndroidRuntime(425): at java.lang.reflect.Method.invoke(Method.java:521) 04-03 16:22:27.238: E/AndroidRuntime(425): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 04-03 16:22:27.238: E/AndroidRuntime(425): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 04-03 16:22:27.238: E/AndroidRuntime(425): at dalvik.system.NativeStart.main(Native Method) 04-03 16:22:27.238: E/AndroidRuntime(425): Caused by: java.lang.NullPointerException 04-03 16:22:27.238: E/AndroidRuntime(425): at org.anddev.andengine.ui.activity.BaseGameActivity.onCreate(BaseGameActivity.java:65) 04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 04-03 16:22:27.238: E/AndroidRuntime(425): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

請幫助。

來源

2012-04-03 user547995

你的空指針從類BaseGameActivity到來。你發佈的代碼並不是拋出錯誤的東西。 logcat中的一行代碼引起的：java.lang.NullPointerException在org.anddev.andengine.ui.activity.BaseGameActivity.onCreate（BaseGameActivity.java:65）'應該是一個很好的暗示。看看我在上面寫的BaseGameActivity – dymmeh 2012-04-03 16:28:44

中的第65行，我使用的框架和多數民衆贊成標準類（我不建立它），所以錯誤必須在我的代碼 – user547995 2012-04-03 16:30:12

那麼，根據logcat輸出錯誤是該框架。所以，無論是框架中都有一個bug，或者你缺少一個步驟來正確設置基類。 – dymmeh 2012-04-03 16:38:05

你的方法

public Engine onLoadEngine() { 
     // TODO Auto-generated method stub 
     return null; 
    }

被返回null。綜觀BaseGameActivity的源代碼，你會看到，在OnCreate它試圖設置它的mEngine變量調用 this.mEngine = this.onLoadEngine();這是呼喚你onLoadEngine（）方法返回空

未來它試圖從該變量訪問的方法使用電話this.applyEngineOptions(this.mEngine.getEngineOptions());

因爲mEngine在此時爲空，所以它會拋出空指針異常。

完成您onLoadEngine方法正確初始化發動機和NullPointerException異常將被固定

編號：BaseGameActivity source code

來源

2012-04-03 16:46:50 dymmeh

Andengine Demo Nullpointer

回答

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