SurefaceView wird als schwares Bild angezeigt!

package com.test;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MyBringBackSurface extends SurfaceView implements Runnable {

    SurfaceHolder ourHolder;
    Thread ourThread = null;
    boolean isRunning;

    public MyBringBackSurface(Context context) {
        super(context);
        ourHolder = getHolder();
        ourThread = new Thread(this);
        ourThread.start();

    }

    @Override
    public void run() {
        // TODO Auto-generated method stub
        while (isRunning) {
            if (!ourHolder.getSurface().isValid())
                continue;
             Canvas canvas = ourHolder.lockCanvas();
             canvas.drawRGB(02, 02, 150);
             ourHolder.unlockCanvasAndPost(canvas);

//            Canvas canvas = ourHolder.lockCanvas();
//            canvas.drawARGB(0, 0, 0, 0);
//            Paint redPaint = new Paint();
//            redPaint.setColor(Color.RED);
//            canvas.drawCircle(100, 100, 30, redPaint);
//            ourHolder.unlockCanvasAndPost(canvas);
        }

    }

}