为什么函数都返回nil ?! 我尝试添加DispathQue,但我不知道它应该是正确的! 请帮助
func storagePutData(uid: String, image: UIImage, compretition: @escaping (Error?) -> Void) -> String {
var downloadURL: String!
let imageName = NSUUID().uuidString
let uploadDara = UIImageJPEGRepresentation(image, 0.1)!
let ref = self.refStorage.child("usersProfileImage/\(uid)/\(imageName).png")
ref.putData(uploadDara, metadata: nil) { (metaDara, error) in
if let err = error {
compretition(err)
}
ref.downloadURL(completion: { (url, error) in
if let err = error {
compretition(err)
} else {
downloadURL = url?.absoluteString
}
})
}
return downloadURL
}
答案 0 :(得分:0)
您将在被调用者函数中的异步函数完成执行之前返回downloadURL
。
此时,它将具有nil
值,这是正确的。
您将希望使用完成处理程序在downloadURL
就绪后返回它,例如-
func storagePutData(uid: String, image: UIImage, success:@escaping (String?)->(), error: @escaping (Error?) -> Void) {
var downloadURL: String!
let imageName = NSUUID().uuidString
let uploadDara = UIImageJPEGRepresentation(image, 0.1)!
let ref = self.refStorage.child("usersProfileImage/\(uid)/\(imageName).png")
ref.putData(uploadDara, metadata: nil) { (metaDara, error) in
if let err = error {
error(err)
}
ref.downloadURL(completion: { (url, error) in
if let err = error {
error(err)
} else {
downloadURL = url?.absoluteString
success(downloadURL)
}
})
}
}