在Android中有没有什么有效的方法来缩小文件中的大图像并将其保存到新文件中，而不会出现OOM异常

public Bitmap decodeSampledBitmapFromFile(String filePath, int reqWidth, int reqHeight) {
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, options);

    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(filePath, options);
}

private int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {
        final int halfHeight = height / 2;
        final int halfWidth = width / 2;

        while ((halfHeight / inSampleSize) >= reqHeight && (halfWidth / inSampleSize) >= reqWidth) {
            inSampleSize *= 2;
        }
    }

    return inSampleSize;
}

public void saveBitmapToFile(Bitmap bitmap, String filePath) {
    File file = new File(filePath);
    FileOutputStream fos = null;
    try {
        fos = new FileOutputStream(file);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 80, fos); // 压缩质量为80%
        fos.flush();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (fos != null) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}