func login(mobile:String,passwd:String,responseResult:(result:NSDictionary?,error:(Int8,String)?)->Void) {
        Alamofire.request(.GET,"http://httpbin.org/get",parameters: ["foo": "bar"])
            .responseString { (request,response,string,error) in
                if error != nil {
                    responseResult(result: nil,error: (error!.code,error!.localizedDescription))
                } else {
                    responseResult(result: nil,error: nil)
                }
        }
   }
   >>>Cannot invoke 'responseResult' with an argument list of type '(result: nil,error: (Int,String))'

这个错误的原因是error!.code是int类型，而声名的是int8类型

修改方法：

func login(mobile:String,passwd:String,responseResult:(result:NSDictionary?,error:(Int,String)?)->Void)