不确定要在代码中放置存储的位置Ref.downloadURL

Question

在将Firebase更新到版本4并更正所有200个错误之后，我剩下2条警告，这会使我的应用程序崩溃。我查找了此错误，并尝试解决该问题，但没有成功：

storageReference.downloadURLWithCompletion()

我一定做错了：

func setUserInfo(_ user: User!, usersname: String, email: String, password: String, cell: String, data: Data!) {

    // Create Path for User Image
    let imagePath = "images/riders/\(user.uid)/Profile Pic/userPic.jpg"

    // Create image Reference
    let imageRef = rDataService.Instance.storageRef.child(imagePath)

    // Create Metadata for the image
    let metaData = StorageMetadata()
    metaData.contentType = "image/jpeg"

    // Save the user Image in the Firebase Storage File
    imageRef.putData(data as Data, metadata: metaData) { (metaData, error) in
        if error == nil {
            let changeRequest = user.createProfileChangeRequest()
            changeRequest.displayName = usersname
            changeRequest.photoURL = metaData?.downloadURL()
            changeRequest.commitChanges(completion: { (error) in

                if error == nil {
                    self.saveUser(user, usersname: usersname, email: email, password: password, cell: cell)

                } else {
                    print(error!.localizedDescription)
                }
            })

        } else {
            print(error!.localizedDescription)
        }
    }

}

此行发生错误：

changeRequest.photoURL = metaData?.downloadURL()

修改

调整后，在此行得到警告：

if let profilepicMetaData = profilepicMetaData {

error: Value 'profilepicMetaData' was defined but never used; consider  replacing with boolean test

应用仍然崩溃：

// Save the user profile Image in the Firebase Storage File
    imageRef.putData(data as Data, metadata: profilepicMetaData) { (profilepicMetaData, error) in
        if let profilepicMetaData = profilepicMetaData {
            imageRef.downloadURL(completion: { (url, error) in

                guard let url = url else {
                    if let error = error {
                        print(error)
                    }
                    return
                }
                let changeRequest = user.createProfileChangeRequest()
                changeRequest.displayName = usersname
                changeRequest.photoURL = url

                changeRequest.commitChanges(completion: { (error) in

                if error == nil {
                    self.saveUser(user, usersname: usersname, email: email, password: password, year: year, makeAndModel: makeAndModel, cell: cell, plateNo: plateNo)

                } else {
                    print(error!.localizedDescription)
                }
            })
        })

        } else {
            print(error!.localizedDescription)
        }
    }

崩溃！

Answer 1

您需要使用原始存储引用对象imageRef来获取下载URL。 （请通过代码检查注释）：

imageRef.putData(data, metadata: profilepicMetaData) {
    // use if let to unwrap the metadata returned to make sure the upload was successful. You can use an underscore to ignore the result
    if let _ = $0 {
        // start the async method downloadURL to fetch the url of the file uploaded
        imageRef.downloadURL {
            // unwrap the URL to make sure it is not nil
            guard let url = $0 else {
                // if the URL is nil unwrap the error, print it 

                if let error = $1 { 
                    // you can present an alert with the error localised description
                    print(error) 
                }
                return
            }
            // your createProfileChangeRequest code  needs to be run after the download url method completes. If you place it after the closure it will be run before the async method finishes.
            let changeRequest = user.createProfileChangeRequest()
            changeRequest.displayName = usersname
            changeRequest.photoURL = url
            changeRequest.commitChanges {
                // unwrap the error and print it
                if let error = $0 {
                    // again you might present an alert with the error
                    print(error)
                } else {
                    // user was updated successfully
                    self.saveUser(user, usersname: usersname, email: email, password: password, year: year, makeAndModel: makeAndModel, cell: cell, plateNo: plateNo)
                }
            }
        }
    } else if let error = $1 {
        // present an alert with the error
        print(error)
    }
}