swift - 收到错误“变量在其自己的初始值内使用”

Question

我正在编写一段新代码，允许用户将图像上传到将保存在 Firebase 数据库和存储中的帖子。然后它将显示在单独的 Viewcontroller 上的 UITableView 中。在我想将照片 url 保存到我的数据库的代码部分，我收到一个错误“变量在其自己的初始值内使用”。我查看了涵盖此问题的其他线程，当我遵循他们的建议时，我得到了一组新的错误。这是我的代码的外观以及出现错误的位置。如果有什么好的建议，谢谢！这是代码：

func postWithImageAndText() {

    var imagesArray = [AnyObject]()

    let postLength = textView.text.count
    let numImages = imagesArray.count
    let postRef = Database.database().reference().child("posts").childByAutoId()
    let storageRef = Storage.storage().reference()
    let uid = Auth.auth().currentUser
    let pictureStorageRef = storageRef.child("users/profile/\(uid)/media")

    let lowResImageData = (imagesArray[0] as! UIImage).jpegData(compressionQuality: 0.50)

            if(postLength>0 && numImages>0)
            {
                let uploadTask = pictureStorageRef.putData(lowResImageData!,metadata: nil)

                {metadata,error in

                    if (error == nil) {
                    let downloadUrl = storageRef.downloadURL { (url, error) in

                        guard let userProfile = UserService.currentUserProfile else { return }

                        let childUpdates = [
                            "author": [
                                "uid": userProfile.uid,
                                "username": userProfile.fullname,
                                "photoURL": userProfile.photoURL.absoluteString
                            ],
                            "text": self.textView.text!,
                            "picture": downloadUrl!.absoluteString,
                            "timestamp": ["sv.":"timestamp"]
                        ] as [String:Any]
                    }
                }
            }
        }
}

`

这部分发生错误："picture": downloadUrl!.absoluteString,

标签： swiftxcodefirebase-realtime-databaseerror-handling

Answer 1

您更新的代码：

func postWithImageAndText() {

    var imagesArray = [AnyObject]()

    let postLength = textView.text.count
    let numImages = imagesArray.count
    let postRef = Database.database().reference().child("posts").childByAutoId()
    let storageRef = Storage.storage().reference()
    let uid = Auth.auth().currentUser
    let pictureStorageRef = storageRef.child("users/profile/\(uid)/media")

    if let lowResImageData = (imagesArray[0] as! UIImage).jpegData(compressionQuality: 0.50) {

      if(postLength>0 && numImages>0)
            {
               pictureStorageRef.putData(lowResImageData, metadata: metaData) { (metadata, error) in

                if error != nil {

                    print("Failed to upload image:", error as Any)

                }

                pictureStorageRef.downloadURL(completion: { (url, error) in

                    if error != nil {

                        print(error!)
                    }
                    if let imageUrl = url?.absoluteString {

                        guard let userProfile = UserService.currentUserProfile else { return }

                        let childUpdates = [
                            "author": [
                                "uid": userProfile.uid,
                                "username": userProfile.fullname,
                                "photoURL": userProfile.photoURL.absoluteString
                            ],
                            "text": self.textView.text!,
                            "picture": imageUrl,
                            "timestamp": ["sv.":"timestamp"]
                        ] as [String:Any]

                    }

                })

         }
      }
   }
}