Question

任何人都可以提供帮助，以便当用户单击客户名称（使用表视图）时，他们的详细信息将显示在第二个视图控制器（VC）上。我认为这是因为我还没有通过documentID来实现这一点。我尝试将documentID添加到Second VC .document（documentID）

初始VC代码

    var customerList = [CustomerLsModel]()
    override func viewDidLoad() {
            super.viewDidLoad()
            let db = Firestore.firestore()

            db.collection("customers").getDocuments() { (snapshot, error) in
                if let error = error{
                    print("Can't get customers: \(error)")
                    let alert = UIAlertController(title: "Error", message: "There was an issue in pulling your information. Please close the application and try again.", preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
                    self.present(alert, animated: true)
                } else {
                    for document in snapshot!.documents{
                        let firstname = document["firstname"]
                        let lastname = document["lastname"]
                        let address = document["address"]
                        let customer = CustomerLsModel(firstname: firstname as! String?, lastname: lastname as! String?, address: address as! String?)

                        self.customerList.append(customer)
                        self.orderAndLimit()
                    }
                    self.customerTable.reloadData()
                }
            }
        }
    }

第二个VC

   let db = Firestore.firestore()
    db.collection("customers").document().getDocument { (document, Error) in
        if let document = document, document.exists{
            self.firstNameLabel.text = document.get("firstname") as? String
        }
    }

这是我的客户模型课程

    class CustomerLsModel{
        var firstname: String!
        var lastname: String?
        var address: String?

        init(firstname: String?, lastname: String?, address: String?){
            self.firstname = firstname
            self.lastname = lastname
            self.address = address
        }

Answer 1

根据Swift的Firebase documentation，如果您使用不带路径参数的方法document()，则将为新文档创建DocumentReference。因此，当您尝试在此参考上使用getDocument时-它为空。

仅当在参数中添加路径时，才会从现有文档中获取数据。

我希望它将对您有帮助！

Answer 2

答案实际上取决于您要如何处理数据，但这是两种方法。但是您的直觉是正确的-您需要跟踪客户的documentId。

因此，当您从Firestore中读取客户并传递所有字符串和documentId以填充每个对象时，您可以这样做

class CustomerLsModel{
   var firstname: String!
   var lastname: String?
   var address: String?
   var docId: String!

   init(firstname: String?, lastname: String?, address: String?, docId: String) {
      self.firstname = firstname
      self.lastname = lastname
      self.address = address
      self.documentId = docId
   }
}

或这样，通过传入Firestore快照使代码更简单

class CustomerLsModel {
   var firstname: String?
   var lastname: String?
   var address: String?
   var docId: String!

    init(withDoc: QueryDocumentSnapshot) {
        self.docId = withDoc.documentID
        self.firstname = withDoc.get("first_name") as? String ?? "no first"
        self.lastname = withDoc.get("last_name") as? String ?? "no last"
        self.address = withDoc.get("addres") as? String ?? "no address"
    }
}

从那里，当用户选择一个客户时，您可以将该对象传递到详细信息视图控制器以进行显示，也可以仅传递docId并将其用于子viewController中以从Firestore读取数据。

大约有100种“传递”数据的方法-Segue是一种流行的选择，您还可以在局部viewController中设置一个“ customer”变量，或者局部可以从主数据库读取数据。这真的取决于您的用例。

在Second View Controller上获取文档参考

2 个答案: