我构建了一个从数据库请求图像url的网络服务。我想在swift上展示它。但是我在varphoto行上发现了这个错误:Cannotconvertvalueoftype'subSequence'(aka'String.CharacterView')totype'String'incollectionletrequestResponse=self.sendToServer(postUrl:"localhost",data:"abc")letSeperated=requestResponse.characters.split(separator:"")varphoto=Seperated[0]

我构建了一个从数据库请求图像url的网络服务。我想在swift上展示它。但是我在varphoto行上发现了这个错误:Cannotconvertvalueoftype'subSequence'(aka'String.CharacterView')totype'String'incollectionletrequestResponse=self.sendToServer(postUrl:"localhost",data:"abc")letSeperated=requestResponse.characters.split(separator:"")varphoto=Seperated[0]