Hi I'm trying to create a variable to go through my database Firebase
each event(in the database EVENT regroups clubs which have events)
must have the function mapviewEdit applied to its content.
ref.child("Events").observe(.value, with: { (snapshot) in
for child in snapshot.children
{
let snapitty = child as! DataSnapshot
myGroupBackTo.notify(queue: .main)
{
print(incrementClub)
incrementClub += 1
multiple = false
print("BACK TO FALSE")
}
myGroupBackTo.enter()
if let result = snapitty.children.allObjects as? [DataSnapshot]
{
for child in result
{
mapviewEdit(incrementClub: incrementClub)
}
myGroupBackTo.leave()}
}
})
{ (error) in
print(error.localizedDescription)
}
}
Here is the beginning of mapviewEdit :
func mapviewEdit(incrementClub: Int){
self.ref.child("Events").child("\(incrementClub)").observeSingleEvent(of: .value, with: {snap in
My problem being that incrementClub does seem to increment to the next club, it always returns the first event of the first club, here is the output (it is normal that it prints x times the same event but not always the first of the first club)
Thanks in advance :)
Related
i just started learning Swift a year ago, so please be patient with me :)
i am downloading JSON data with a network call, and as soon as i successfully received those rows, i then continue to clear the rows inside my coreData entity, and rewrite those new rows into coredata..
i am having a hard time understanding this asynchronous procedure..
what i've learned is that i have to use completion handlers, but i still can't use it the way i need to.. especialy when i need to proceed after those 3 steps were executed..
First call from button action:
#IBAction func updateButtonPressed(_ sender: Any) {
self.myCoreData.update() {(success) in // calls my update method
print(success!)
textField.text = success! // not possible bc not in the Mainthread
}
textField.text = "blabla" // gets executed before the result is available
methods:
func update(completion: #escaping (String?) -> Void) { //parent method which calls sub methods
var returnValue = ""
Step1getJson {_ in. // step 1
self.Step2Delete { // step 2
self.Step3Save { // step 3
returnValue = "return Value: \(self.step1Result)"
completion(returnValue)
}
}
}
}
func Step1getJson(completion: #escaping (Bool) -> ()) {
var success = false
if let url = URL(string: "https:foo") {
URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data else { return }
do {
let parsedJSON = try JSONDecoder().decode([RemoteWire].self, from: data)
print("-- Successfully received \(parsedJSON.count) datarows ")
self.JSON = parsedJSON
self.step1Result = "-- Successfully received \(parsedJSON.count) datarows "
success = true
} catch {
print(error)
}
completion(success)
}.resume()
}
}
func Step2Delete(completion: () -> Void) {
...delete entity rows
completion()
}
func Step3Save(completion: () -> Void) {
.. save new JSON rows to coreData
completion()
}
Everything is working fine that far, and step 2 and step 3 get successfully called when network download has finished..
but how can i proceed after those steps were executed inside my updateButtonPressed function?
if i try to write those results into any UI element inside my completion block, a textField or whatever, i get an error that this has to happen in the main thread, and if i execute it outside the completion block those lines get executed far too early, when no results are available yet.
i feel like i have understanding problem with this, i hope you guys can help me out and guide me in the right direction.
As swift allows any changes or updates in UI element only from main thread, you need to call the main thread to update the UI.
Replace the below code
#IBAction func updateButtonPressed(_ sender: Any) {
self.myCoreData.update() {(success) in // calls my update method
print(success!)
textField.text = success! // not possible bc not in the Mainthread
}
}
with the new code
#IBAction func updateButtonPressed(_ sender: Any) {
self.myCoreData.update() {(success) in // calls my update method
print(success!)
DispatchQueue.main.async {
textField.text = success! // Now possible because it is in main thread
}
}
}
Trying to query a document and then update it in a function in my ViewModel. Trying something like the below, but it doesn't work. Any advice would be appreciated!
func addToFruits(name: String) {
db.collection("fruits").whereField("name", isEqualTo: name)
.getDocument()
.limit(to: 1)
.updateData(["fruits": FieldValue.arrayUnion([name])])
}
func addToRoutine(routine: String, habit: String) {
db.collection("routines").whereField("name", isEqualTo: routine).getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
document.updateData(["habits": FieldValue.arrayUnion([habit])])
}
}
}
}
In the first one, error I get is "Value of type 'Query' has no member 'getDocument'" and not sure how to resolve this. Second one, error I get is "Value of type 'QueryDocumentSnapshot' has no member 'updateData'"
It's not exactly clear what you're attempting to update but here's some quick example code that will read in a user named 'Steve' and update his age to 50. Keep in mind this will read in the FIRST user named 'Steve' and update their age - then when it's run again, will read the NEXT Steve etc etc - that may be what your attempting to do.
func readUsersAndUpdateTheirAgeTo50() {
let users = self.db.collection("users") //self.db points to *my* firestore
users.whereField("name", isEqualTo: "Steve").limit(to: 1).getDocuments(completion: { querySnapshot, error in
if let err = error {
print(err.localizedDescription)
return
}
guard let docs = querySnapshot?.documents else { return }
for doc in docs {
let docId = doc.documentID
let name = doc.get("name")
print(docId, name)
let ref = doc.reference
ref.updateData(["age": 20])
}
})
}
If I just wanted to update all Steve's age to 50, remove the limit
.limit(to: 1)
Note this code is kind of sloppy as since there is a limit of 1, we wouldn't need the loop. Also note that not every Steve is 50 so there should be additional parameters to narrow down which Steve it is - like a uid for example.
Using Swift code 5.1 I have managed to update Firestore Database with items in current users basket but not able to add/update quantity. Currently if I wanted to add an item that already exist in the basket it simply adds another line but I wanted to just update quantity.
Can you advise me on how to create a function that adds quantity?
Here are the codes I have so far. Only relevant sections of code pasted.
Firestore DB function in my Helper file:
enum FCollectionReference: String {
case User
case Category
case Items
case Basket
case Orders
}
func FirebaseReference(_ collectionReference: FCollectionReference) -> CollectionReference {
return Firestore.firestore().collection(collectionReference.rawValue)
}
Here's the code in in my Basket Model file using
class Basket {
var id: String!
var ownerId: String!
var itemIds: [String]!
var delivery: Float!
var admin: Float!
var quantity: Int!
init() {
}
init(_dictionary: NSDictionary) {
id = _dictionary[kOBJECTID] as? String
ownerId = _dictionary[kOWNERID] as? String
itemIds = _dictionary[kITEMIDS] as? [String]
delivery = _dictionary[kDELIVERY] as? Float
admin = _dictionary[kADMIN] as? Float
quantity = _dictionary[kQUANTITY] as? Int
}
}
//MARK: Helper functions
func basketDictionaryFrom(_ basket: Basket) -> NSDictionary {
return NSDictionary(objects: [basket.id, basket.ownerId, basket.itemIds, basket.quantity], forKeys: [kOBJECTID as NSCopying, kOWNERID as NSCopying, kITEMIDS as NSCopying, kQUANTITY as NSCopying,kDELIVERY as NSCopying, kADMIN as NSCopying])
}
//MARK: - Update basket
func updateBasketInFirestore(_ basket: Basket, withValues: [String : Any], completion: #escaping (_ error: Error?) -> Void) {
FirebaseReference(.Basket).document(basket.id).updateData(withValues) { (error) in
completion(error)
Codes in Item View Control to add items to basket:
#objc func addToBasketButtonPressed() {
//check if user is logged in or show login view
if MUser.currentUser() != nil {
downloadBasketFromFirestore(MUser.currentId()) { (basket) in
if basket == nil {
self.createNewBasket()
}else {
basket?.itemIds.append(self.item.id)
self.updateBasket(basket: basket!, withValues: [kITEMIDS: basket!.itemIds])
}
}
} else {
showLoginView()
}
}
private func updateBasket(basket: Basket, withValues: [String : Any]) {
updateBasketInFirestore(basket, withValues: withValues) { (error) in
if error != nil {
self.hud.textLabel.text = "Error: \(error!.localizedDescription)"
self.hud.indicatorView = JGProgressHUDErrorIndicatorView()
self.hud.show(in: self.view)
self.hud.dismiss(afterDelay: 2.0)
print("error updating basket", error!.localizedDescription)
}else {
self.hud.textLabel.text = "Added to Basket"
self.hud.indicatorView = JGProgressHUDSuccessIndicatorView()
self.hud.show(in: self.view)
self.hud.dismiss(afterDelay: 2.0)
}
}
}
To clarify my request, what do I need to change/re-arrange in my coding so the Database Cloud Firestore is arranged in order shown in my attached screen shot. First screen shot showing current layout in the last column and I'm trying to change this to layout demonstrated in the second screen shot?
I think you are asking how to update the value in a field within a Firestore document. If not, let me know and I will update the answer.
Here's some code that updates the qty of an item in inventory. Pass in the qty to add as a + Int and then to subtract as a - Int. The structure looks like this
root
inventory
item_0
qty: 0
and the code to update the qty node is:
func incrementQty(deltaQty: Int) {
let docToUpdate = self.db.collection("inventory").document("item_0")
docToUpdate.updateData( [
"qty": FieldValue.increment( Int64(deltaQty) )
])
}
call it like this
self.incrementQty(deltaQty: 4) //adds 4 to the existing qty
previously, incrementing values had to be wrapped into a transaction to make it safe but the FieldValue makes it much easier.
I am adding another answer based on comments and question clarification. My other answer still stands as an answer but it's a different approach.
Arrays are inherently hard to work with in NoSQL databases as they are often treated as a single object. They have limited functionality opposed to collections, documents and fields, and can't directly be sorted or have items inserted. And querying is well, challenging. Firestore does a great job at providing better interoperability with arrays but there are still usually better options.
Instead of an array, I would change the structure to this:
Baskets (collection)
basket_number (document in the Baskets collection, like you have now)
items //a collection of items in the basket
item_0 //a document with the docID being the the item number
item_qty: //qty of the item
item_1
item_qty:
item_2
item_qty:
So the downside of .updateData is that if the field being updated doesn't exist, it doesn't create the field, it simply throws an error. So we need to test to see if the document exists first, if so, update with updateData, if not create the item with an initial quantity.
Here's the code that does it - note for simplicity I am ignoring the top level Basket and basket_number since you already know how to do that part and focused on the items collection and down.
func incrementQty(itemNumberToUpdate: String, deltaQty: Int) {
let docToUpdate = self.db.collection("items").document(itemNumberToUpdate)
docToUpdate.getDocument(completion: { documentSnapshot, error in
if let err = error {
print(err.localizedDescription)
return
}
if let _ = documentSnapshot?.data() {
print("item exists, update qty")
docToUpdate.updateData([
"item_qty": FieldValue.increment( Int64(deltaQty) )
], completion: { err in
if let err = err {
print("Error updating document: \(err.localizedDescription)")
} else {
print("Item qty successfully updated")
}
})
} else {
print("no item exists, need to create")
docToUpdate.setData([
"item_qty": FieldValue.increment( Int64(deltaQty) )
], completion: { err in
if let err = err {
print("Error updating document: \(err.localizedDescription)")
} else {
print("Item successfully created with initial quantity")
}
})
}
})
}
Pass in an item number and the quantity to either modify the existing qty by, or will be the initial quantity.
self.incrementQty(itemNumberToUpdate: "item_0", deltaQty: 5)
In my application the main entity is threads, I mean sneakers, jackets, t-shorts and so on.
This is firebase db:
I have logic witch fetch threads by 'threadTypes'. In my app there're 3 types - outwear, footwear and accessory.
That is code:
extension GoodsViewController {
func fetchThreads(completion: #escaping (Swift.Void) -> Swift.Void) {
self.ref
.child("threads")
.observeSingleEvent(of: .value, with: { (snapshot) in
for rest in snapshot.children.allObjects as! [FIRDataSnapshot] {
guard let restDict = rest.value as? [String: Any] else { continue }
let thread = Thread()
thread.setValuesForKeys(restDict)
if Search.searchFilters.stuffTypes.isEmpty {
self.threads.append(thread)
}
else {
if let threadType = thread.threadType {
if Search.searchFilters.stuffTypes.contains(threadType) {
self.threads.append(thread)
}
}
}
}
completion()
})
}
}
self.threads - is variable which is used as table view datasource.
Search.searchFilters.stuffTypes - array which contains types for search.
As you see I fetch all threads and then check if current thread type contains in Search.searchFilters.stuffTypes array.
My question is - is it possible to perform this checking before I fetch all threads?
In C# it should be something like that -
threads.Where(t => Search.searchFilters.stuffTypes.Contains(t.threadType)
I would like to download from firebase:
data issued from a group profile (Firebase realtime DB)
including...
data issued from the group admin profile (Firebase realtime DB)
a group profile image (Firebase Storage)
Then I can instantiate a group object with its data and its image
First approach, I used 3 nested closures that allowed me to get data, and then to get the image.
It did work, but it was quite long to get sequentially all that stuffs from firebase.
So I tried to use GCD in order to push my 2 latest Firebase queries (user data + group image) at the same time (rather than one after the other), and to wait for the last callback to start instantiating my group.
Is it a correct approach ?
If yes, I find some difficulties to implement it...
My issue : returnedUser and returnedGroupImage are always nil
Here is my bunch of code :
static func getGroup(_ groupID:String, completionBlock: #escaping (_ group: Group?) -> ()) {
dataRef.child("data").child("groups").child(groupID).observe(.value, with: { (snapshot) in
if let snapshotValue = snapshot.value {
guard let name = (snapshotValue as AnyObject).object(forKey: "name") as? String else
{
completionBlock(nil)
return
}
guard let adminID = (snapshotValue as AnyObject).object(forKey: "adminID") as? String else
{
completionBlock(nil)
return
}
let queue = DispatchQueue(label: "asyncQueue", attributes: .concurrent, target: .main)
let dispatch_group = DispatchGroup()
var returnedUser: User?
var returnedGroupImage: UIImage?
queue.async (group: dispatch_group) {
FireBaseHelper.getUser(adminID, completionBlock: { (user) in
if user != nil {
returnedUser = user
}
})
}
queue.async (group: dispatch_group) {
FireBaseHelper.getGroupImage(groupID, completionBlock: { (image) in
if image != nil {
returnedGroupImage = image
}
})
}
dispatch_group.notify(queue: DispatchQueue.main) {
// Single callback that is supposed to be executed after all tasks are complete.
if (returnedUser == nil) || (returnedGroupImage == nil) {
// always true !
return
}
let returnedGroup = Group(knownID: (snapshotValue as AnyObject).key, named: name, createdByUser: currentUser!)
returnedGroup.groupImage = returnedGroupImage
completionBlock(returnedGroup)
}
}
})
}
Thanks for your help !
I believe that the way you are using DispatchGroups are not correct.
let dispatch_group = DispatchGroup()
var returnedUser: User?
var returnedGroupImage: UIImage?
dispatch_group.enter()
FireBaseHelper.getUser(adminID, completionBlock: { (user) in
if user != nil {
returnedUser = user
}
dispatch_group.leave()
})
dispatch_group.enter()
FireBaseHelper.getGroupImage(groupID, completionBlock: { (image) in
if image != nil {
returnedGroupImage = image
}
dispatch_group.leave()
})
dispatch_group.notify(queue: DispatchQueue.main) {
// Single callback that is supposed to be executed after all tasks are complete.
if (returnedUser == nil) || (returnedGroupImage == nil) {
// always true !
return
}
let returnedGroup = Group(knownID: (snapshotValue as AnyObject).key, named: name, createdByUser: currentUser!)
returnedGroup.groupImage = returnedGroupImage
completionBlock(returnedGroup)
}