我可以调用UIImageWriteToSavedPhotosAlbum并毫无问题地处理完成:classA{funcsaveNow(){UIImageWriteToSavedPhotosAlbum(someImage,self,"saveImage:didFinishSavingWithError:contextInfo:",nil)}funcsaveImage(image:UIImage,didFinishSavingWithErrorerror:NSError?,contextInfo:UnsafePointer){//handlecompletion}}但是,如果我想让saveNo