问题出在相册的照片质量上。
如果您将捆绑包中的qr图像文件替换为 image，例如[UIImage imageNamed：@ foobar.png]，则会显示qr结果。
顺便说一句，我尝试了可能的照片，但没有运气使它起作用。

the issue is on photo quality in the photo album. if you put a qr image file from bundle replacing "image" e.g.. [UIImage imageNamed:@"foobar.png"], the qr result will appear. By the way, I tried may photos, no luck to get it works.