Question

我尝试使用下面的if语句检查是否有图像：

var profileImage = UIImage()


 @IBAction func submitAction(_ sender: Any) {


    if profileImage != 0 && nameTextField.text != nil {


    let storageRef = FIRStorage.storage().reference()
    let databaseRef = FIRDatabase.database().reference()

    let uid = FIRAuth.auth()?.currentUser?.uid

    let profileImageData = UIImageJPEGRepresentation(self.profileImage, 0.4)

    let profileImageRef = storageRef.child("ProfileImages/\(uid)/profileImage.jpg")
    profileImageRef.put(profileImageData!, metadata: nil) {
        metadata, error in

        if error != nil{

            print("error!")

        }
        else{

            let downloadURL = metadata?.downloadURL()
            let username = self.nameTextField.text
            let user : [NSObject : AnyObject] = ["uid" as NSObject : uid! as AnyObject, "username" as NSObject : username! as AnyObject, "profileImageURL" as NSObject : downloadURL! as AnyObject]



            let childUpdates = ["Users/\(uid)/" : user]
            databaseRef.updateChildValues(childUpdates)

        }
        }
        }

    }

然而它返回错误：

＆＃39;二元运算符＆＃39;！=＆＃39;不能应用于＆＃34; UIImage＆＃39;

类型的操作数

我也尝试用0替换0，但这不适用于UIImage。

Answer 1

将profileImage定义为可选项，然后您可以使用guard语句检查它是否具有值。

var profileImage:UIImage?
guard let profileImage = profileImage, let name = nameTextField.text else { return}
let storageRef = FIRStorage.storage().reference()
let databaseRef = FIRDatabase.database().reference()
...

二元运算符＆＃39;！=＆＃39;不能应用于＆＃34; UIImage＆＃34;类型的操作数。

1 个答案: