將數據從活動傳遞到類

我的遊戲存在問題。我有一個主要活動，它顯示了我繪製遊戲的表面視圖。現在我想從我的主要活動傳遞數據到一個類，但每次我嘗試這個我得到一個錯誤，並在LogCat我看到錯誤發生在我傳遞數據的行。在這裏我的代碼 MainActivity：將數據從活動傳遞到類

public class Banka { 
public GameView gameView; 

public float currentX = 0; 
public float currentY = 0; 
public boolean touchDownTrue = false; 

public Banka (float x, float y, boolean touch){ 
    this.currentX = x; 
    this.currentY = y; 
    this.touchDownTrue = touch; 
    gameView.isReady(); 
}

，在這裏我的logcat錯誤：接收到的數據

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    requestWindowFeature(Window.FEATURE_NO_TITLE); 
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); 
    setContentView(R.layout.main); 
} 
public boolean onTouchEvent(MotionEvent event) { 
      currentX = event.getX(); 
    currentY = event.getY(); 
    if(event.getAction() == MotionEvent.ACTION_DOWN){ 
     touchDisplay = true; 
     banka = new Banka(currentX, currentY, touchDisplay); 
    } 
    if(event.getAction() == MotionEvent.ACTION_UP){ 
     touchDisplay = false; 
     banka = new Banka(currentX, currentY, touchDisplay); 
    } 
    return super.onTouchEvent(event); 
}

類

這裏的logcat：

thread exiting with uncaught exception (group=0x4001b188) Uncaught handler: thread main exiting due to uncaught exception java.lang.NullPointerException at com.whlabs.nameless.Banka.(Banka.java:14) at com.whlabs.nameless.MainActivity.onTouchEvent(MainActivity.java:31) at android.app.Activity.dispatchTouchEvent(Activity.java:2064) at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) at android.view.ViewRoot.handleMessage(ViewRoot.java:1691) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:123) at android.app.ActivityThread.main(ActivityThread.java:4363) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:521) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) at dalvik.system.NativeStart.main(Native Method)

來源

2011-10-24 Miljenko Simovic

什麼是錯誤？ Banka在哪裏初始化gameView？ – EightyEight

你能否發佈你得到的完整錯誤？ –

@Eightight - 因爲在我得到這個工作後，會有更多的代碼包含GameView類。 –

我猜測你得到一個NullPointerException，因爲你沒有初始化gameView。解決這個問題的一種方法是在您的構造函數中初始化gameView，如下所示：

public Banka (float x, float y, boolean touch){ 
    this.currentX = x; 
    this.currentY = y; 
    this.touchDownTrue = touch; 
    gameView = new GameView(); 
    gameView.isReady(); 
}

來源

2011-10-24 21:56:26

將數據從活動傳遞到類

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