c# - Monodroid BitmapFactory.DecodeFileDescriptor位图始终为null

我使用以下方法来防止内存不足异常，但是Bitmap ist始终为null。有人知道吗？

public Bitmap readBitmap(Android.Net.Uri selectedImage) {

        Bitmap bm = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.InSampleSize = 9;
        AssetFileDescriptor fileDescriptor = null;
        try {
            fileDescriptor =  this.ContentResolver.OpenAssetFileDescriptor(selectedImage,"r");
        } catch (FileNotFoundException e) {
            Toast.MakeText(this, e.Message, ToastLength.Long);
        }
        finally{
            try {
                bm =  BitmapFactory.DecodeFileDescriptor(fileDescriptor.FileDescriptor, null, options);
                fileDescriptor.Close();
            } catch (IOException) {
            }
        }
        return bm;
}

最佳答案

是。这是Google的另一个错误。解决方案是这样做：

bm =  BitmapFactory.decodeStream(new FileInputStream(fileDescriptor));

代替

bm =  BitmapFactory.DecodeFileDescriptor(fileDescriptor.FileDescriptor, null, options);