ios - 带有完成处理程序的 storageReference.downloadURL ... url 不断返回 nil

Question

出于某种原因，当我使用 firebase 存储检索我的下载图像 URL(我已确认该图像实际上已发送到 firebase 存储)时，该 url 返回 nil。我很确定我的文件路径匹配/正确，但我不确定我哪里出错了。

let selectedImageData=UIImageJPEGRepresentation(selectedImage.image!, 1)
    let storageRef=Storage.storage().reference()
    let metadata=StorageMetadata()
    storageRef.child("Users").child(Auth.auth().currentUser!.uid)
        .child("Pictures"+String(self.tracker)).putData(selectedImageData!, metadata: metadata) 
    { 
        (metadata, error) in

        if error != nil{
            print("There was a problem uploading")
            return
        }

        storageRef.child("Users").child(Auth.auth().currentUser!.uid)
            .child("Pictures"+String(self.tracker)).downloadURL(completion: 
        { 
            (url, error) in

            print("What's going on")
            self.pictures.append((url?.absoluteString)!)
        })
    }

Answer 1

使用下面的代码将图片上传到存储并获取图片的返回路径

let selectedImageData=UIImageJPEGRepresentation(selectedImage.image!, 1)
self.uploadProfileImageToFirebase(data: selectedImageData)

func uploadProfileImageToFirebase(data:NSData){

let storageRef = Storage.storage().reference().child("Users").child(Auth.auth().currentUser!.uid).child("Pictures").child(String(self.tracker)) 
//Modify the above line as per your requirement

if data != nil {
    storageRef.putData(data as Data, metadata: nil, completion: { (metadata, error) in
        if(error != nil){
            print(error)
            return
        }

        // Fetch the download URL
        storageRef.downloadURL { url, error in
            if let error = error {
                // Handle any errors
                if(error != nil){
                    print(error)
                    return
                }
            } else {
                // Get the download URL
                let urlStr:String = (url?.absoluteString) ?? ""
                print(urlStr)
            }
        }
    })
}