在doInBackground（）中执行错误

Question

这是我显示图像的地方 它是一个放在imageview中的画布，然后使用asynctask绘制 我希望你能帮助我，请解释我的代码中的错误。 但不断收到此错误：

这是我的代码：

private Bitmap mImageone, mImagetwo, mImagethree, mImagefour;
private Bitmap mBackground;
private BitmapDrawable mBitmapDrawable;
private static String mTempDir;
private FileOutputStream mFileOutputStream = null;
private Canvas mCanvas;


   public class ImageAsyctask extends AsyncTask<Bitmap, Void, Bitmap> {

    private final WeakReference<Bitmap> imageViewReference;

    public ImageAsyctask(Bitmap bitmap) {
        imageViewReference = new WeakReference<Bitmap>(bitmap);
    }

    @Override
    protected Bitmap doInBackground(Bitmap... params) {
        // TODO Auto-generated method stub
        mTempDir = Environment.getExternalStorageDirectory()
                + "/MyCameraBooth/Photo/";

        File mTempFile = new File(mTempDir);
        if (!mTempFile.exists()) {
            mTempFile.mkdirs();
        }

        mBackground = Bitmap
                .createBitmap(1800, 1200, Bitmap.Config.RGB_565);
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;

        f = new File(AppConstant.filepathone);
        Bitmap mImageone = decodeFile(f);
        g = new File(AppConstant.filepathtwo);
        Bitmap mImagetwo = decodeFile(g);
        h = new File(AppConstant.filepaththree);
        Bitmap mImagethree = decodeFile(h);
        i = new File(AppConstant.filepathfour);
        Bitmap mImagefour = decodeFile(i);

        j = new File(sharedpreferences.getString("positionImage",
                "positionImage"));
        Bitmap mbGG = decodeFile(j);

        Bitmap mBack = Bitmap.createScaledBitmap(mbGG, 1800, 1200, true);
        Bitmap mImaget = Bitmap.createScaledBitmap(mImagetwo, 515, 360,
                true);
        Bitmap mImageth = Bitmap.createScaledBitmap(mImagethree, 515, 360,
                true);
        Bitmap mImagef = Bitmap.createScaledBitmap(mImagefour, 515, 360,
                true);
        Bitmap mImageo = Bitmap.createScaledBitmap(mImageone, 1085, 635,
                true);

        mCanvas = new Canvas(mBackground);
        mCanvas.drawARGB(255, 150, 150, 10);
        if (sharedpreferences.getString("positionImage", "positionImage")
                .contains("FrameA")) {
            mCanvas.drawBitmap(mBack, 0, 0, null);
            mCanvas.drawBitmap(mImaget, 75, 75, null);
            mCanvas.drawBitmap(mImageo, 75, 490, null);
            mCanvas.drawBitmap(mImageth, 645, 75, null);
            mCanvas.drawBitmap(mImagef, 1215, 75, null);
        } else if (sharedpreferences.getString("positionImage",
                "positionImage").contains("FrameB")) {
            mCanvas.drawBitmap(mBack, 0, 0, null);
            mCanvas.drawBitmap(mImaget, 75, 75, null);
            mCanvas.drawBitmap(mImageo, 645, 490, null);
            mCanvas.drawBitmap(mImageth, 645, 75, null);
            mCanvas.drawBitmap(mImagef, 1215, 75, null);
        } else if (sharedpreferences.getString("positionImage",
                "positionImage").contains("FrameC")) {
            mCanvas.drawBitmap(mBack, 0, 0, null);
            mCanvas.drawBitmap(mImaget, 75, 765, null);
            mCanvas.drawBitmap(mImageo, 645, 75, null);
            mCanvas.drawBitmap(mImageth, 645, 765, null);
            mCanvas.drawBitmap(mImagef, 1215, 765, null);
        } else if (sharedpreferences.getString("positionImage",
                "positionImage").contains("FrameD")) {
            mCanvas.drawBitmap(mBack, 0, 0, null);
            mCanvas.drawBitmap(mImaget, 75, 765, null);
            mCanvas.drawBitmap(mImageo, 75, 75, null);
            mCanvas.drawBitmap(mImageth, 645, 765, null);
            mCanvas.drawBitmap(mImagef, 1215, 765, null);
        }
        Log.e(sharedpreferences.getString("positionImage", "positionImage"),
                sharedpreferences.getString("positionImage",
                        "positionImage"));

        return mBackground;
    }


    @Override
    protected void onPostExecute(Bitmap result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);

        try {
            String friendlydate = DateFormat.getTimeInstance(
                    DateFormat.MEDIUM).format(new Date());
            friendlydate = friendlydate.replace(':', '_');
            String filename = friendlydate + ".jpg";
            mBitmapDrawable = new BitmapDrawable(mBackground);
            Bitmap mNewSaving = mBitmapDrawable.getBitmap();
            String FtoSave = mTempDir + filename;
            File mFile = new File(FtoSave);
            mFileOutputStream = new FileOutputStream(mFile);
            mNewSaving.compress(Bitmap.CompressFormat.PNG, 100,
                    mFileOutputStream);

            imVCature_pic.setImageBitmap(decodeSampledBitmapFromFile(
                    mFile.getAbsolutePath(), 150, 150));

            f.delete();
            i.delete();
            g.delete();
            h.delete();

            // imVCature_pic.setImageBitmap(decodeFile(mFile));
            mFileOutputStream.flush();
            mFileOutputStream.close();
            mFileOutputStream = null;

        } catch (FileNotFoundException e) {
            Log.e(AppConstant.TAG,
                    "FileNotFoundExceptionError " + e.toString());
        } catch (IOException e) {
            Log.e(AppConstant.TAG, "IOExceptionError " + e.toString());
        }
        Log.i(AppConstant.TAG, "Image Created");
    }

}

并运行它：    新的ImageAsyctask（mBackground）.execute（）;