I've been stuck all day, I'm trying to implement a chart on my app that has to collect some data from my firebase database to use them to populate the chart.
I've try this code to get the data from the database:
let userID = Auth.auth().currentUser?.uid
let bslChecksDB = Database.database().reference().child("BSL Checks").child(userID!)
bslChecksDB.observe((.childAdded)) { (snapshot) in
print(snapshot)
let snapshotValue = snapshot.value as! [String : [String: String]]
print(snapshotValue)
self.arrayOfDic = Array(snapshotValue.values)
for i in 0...self.arrayOfDic.count - 1 {
self.snapshotDictionary = self.arrayOfDic[i]
let date = self.snapshotDictionary["Date"]!
let time = self.snapshotDictionary["Time"]!
let bsl = Double(self.snapshotDictionary["BSL"]!)
let unit = self.snapshotDictionary["Unit"]!
let dateTime = "\(date) at: \(time)"
self.dateTimeArray.append(dateTime)
self.bslDataArray.append(bsl!)
self.uuuuDataArray.append(unit)
}
I try to print the various arrays to see if they were made and they were, so no problem (i thought). then when I proceed to upload those data on the chart, they disappear.... It seems like my arrays are wiped out as soon as they are made! What is wrong?
for i in 0...self.dateTimeArray.count - 1 {
ChartFormatter().array.append(self.dateTimeArray[i])
}
print("array")
print(ChartFormatter().array)
}
var lineChartEntry = [ChartDataEntry] ()
print(dateTimeArray.count)
for i in 0...dateTimeArray.count - 1 {
let value = ChartDataEntry(x: Double(i), y: bslDataArray[i])
lineChartEntry.append(value)
}
let line1 = LineChartDataSet(values: lineChartEntry, label: "BSL")
line1.colors = [NSUIColor.blue]
let data = LineChartData ()
data.addDataSet(line1)
chtChart.data = data
chtChart.chartDescription?.text = "My graph"
Since this is the first time I implement a chart on my app, could you please explain how to populate the chart with data from a firebase database? thanks
Related
Please help me understand the logic reading data from the Firestore document, if one of the values is an array. I tried other answers here and sources but never came to a simple working way and understand clearly. Firestore document structure — example. And Swift class targets for saving (conditional):
struct MyStruct {
var name: String
var pages: Int
}
let part1 = [MyStruct]()
let name1 = ""
let pages1 = 0
let part2 = [MyStruct]()
let name2 = ""
let pages2 = 0
func readFirestore() { }
What should the document reader function look like to add data to existing targets in the class? Thanks in advance for any help in improving my understanding!
They helped to deal with familiar, thank you for what they are. As expected, everything is simple. But for the beginner there is nothing more difficult than simplicity 😁
func readFirestore() {
self.db.collection("example").document("book").getDocument { (document, error) in
if error == nil {
if document != nil && document!.exists {
//get all document data
guard let documentData = document!.data() else {return}
//get value-array for key "part1"
let element = documentData["part1"] as? [Any] //print -> Optional([name1, 100])
//get first element in array
guard let nameDB = element?[0] as? String else {return} //print -> name1
guard let pagesDB = element?[1] as? String else {return} //print -> 100
//append in class
part1.append(MyStruct(name: nameDB, pages: pagesDB))
name1 = nameDB
pages1 = pagesDB
}
}
}
}
I need to retrieve price value of each product in the cart child, but how should I retrieve it and sum the retrieved value together?
Picture of my Firebase database structure
let uid = Auth.auth().currentUser?.uid
refProduct = Database.database().reference().child("users").child(uid!).child("cart")
refProduct.observeSingleEvent(of: .value) { (snapshot) in
for cartchild in snapshot.children{
let snap = cartchild as! DataSnapshot
let key = snap.value
.....
}
}
I would not store the price as a string, but as a number. You might want to add another field with currency if needed.
guard let uid = Auth.auth().currentUser?.uid else { return }
var sum: Double = 0
refProduct = Database.database().reference().child("users").child(uid).child("cart")
refProduct.observeSingleEvent(of: .value) { (snapshot) in
for cartchild in snapshot.children{
let snap = cartchild as! DataSnapshot
let data = snap.value as? [String: Any]
let price = data["ProductPrice"] as? Double ?? 0
sum += price
}
print("Final sum: \(sum)")
}
Not really tested, but this is the idea
Arvidurs is correct about storing the price as an int and the currency as a string, but the reason the answer isn't working for you is that it doesn't address that you're not correctly retrieving the data you want in the first place.
You have your cart folder, and it contains two product folders whose properties you're trying to retrieve. You can't retrieve and unwrap the values contained in those two folders by just referencing the parent cart folder. You need to individually access each folder within cart:
Database.database().reference().child("users").child(uid).child("cart").child("-Lf59bkQ5X3ivD6ue1SA")
Database.database().reference().child("users").child(uid).child("cart").child("-Lf5MiEGU357HWTMbxv8")
However, for this to work, you'll need access to each products autoID value, so you'll need to be storing each new product's childByAutoID value into an array or a dictionary so that you have them all available to access whatever data you need.
You'll need to implement this as you're storing the new product to the cart folder. I don't know exactly how you're currently saving each product, but you'll need to do something like this when you create your reference that you'll be saving to:
let newProductRef = Database.database().reference().child("users").child(uid).child("cart").childByAutoId()
let autoID = newProductRef.key
At that point, you'll be able to store autoID however you choose, and you'll have access to everything within the cart folder, and you can loop through all of your autoIDs and get whatever data you need. Example:
func getCartPriceSum(finished: #escaping ([String : Double]) -> Void){
let myGroup = DispatchGroup()
var sum = Double()
var currency = String()
for autoID in autoIdArray{
myGroup.enter()
let productRef = Database.database().reference().child("users").child(uid).child("cart").child(autoID)
productRef.observe(.value) { (snapshot) in
guard
let snapshotValue = snapshot.value as? NSDictionary,
let productPrice = snapshotValue["ProductPrice"] as? Double,
let priceCurrency = snapshotValue["PriceCurrency"] as? String//assuming you've adopted Arvidurs' method of storing the price data
else {
print("productPrice/priceCurreny nil")
return
}
sum += productPrice
currency = priceCurrency
}
myGroup.leave()
}
let priceSum = [currency : sum]
myGroup.notify(queue: .main) {
finished(priceSum)
}
}
And you could call the function like this:
getCartPriceSum { (priceSum) in
//do whatever you want with the priceSum
}
The only thing left for you to figure out is how you want to store those autoIDs.
Below I have some data in firestore.
I have a an array in the _geoloc field. Each of those indexes have latitude and longitude coordinates. So using SWIFT I want to be able to only get the lat and lng coordinates at index 0 and pass them to individually to a string. I have been researching for days and I am stuck. I have tried to create a new array of strings or an AnyObject array and I just get stuck with retrieving the data I need at index 0, and passing only those 2 lat/lng coordinates to string values. I have several failed snippets of code I could post.
Here is a snippet of what I was attempting to do: (I am really new to firebase so the code is a bit ugly as I am just trying to figure this out)
Firestore.firestore().collection("users").document("626").getDocument { (document, error) in
if let document = document {
// let geo_array = document["_geoloc"]
var yourArray = [String]()
// let geo_location = [geo_array] as [AnyObject]
let array: [Any] = document["_geoloc"] as! [Any]
let tmpArray = array.map({ return String(describing: $0)})
let string = tmpArray.joined(separator: ",")
yourArray.append(string)
print(yourArray[0])
You just need to cast your object from Any to an array of dictionaries and get the first property:
Firestore.firestore().collection("users").document("626").getDocument { document, error in
if let document = document {
var yourArray: [String] = []
if let location = (document["_geoloc"] as? [[String:Double]])?.first,
let latitude = location["lat"],
let longitude = location["lon"] {
let coordinate2d = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
yourArray.append("Latitude: \(location.latitude), Longitude: \(location.Longitude)")
}
}
}
Maybe first declare this:
var firstPositionValues = [AnyObject]()
Then get it like this:
let db = Firestore.firestore().collection("users").document("626")
db.getDocument { (document, error) in
if let document = document {
let geo_location = document["_geoloc"] as [AnyObject] // <- this is all of them in the document
var initialValues = geo_location[0] // <- here are your lat and lng at position 0
self.firstPositionValues = initialValues
}
Hope I understood correctly good luck.
I am trying to retrieve a child of a child. the entire snapshotValue returns null. When I retrieve the same data as a child (not nested) it retrieves fine.
I'm Using XCode 10 and Swift 4
To troubleshooting purposes, I have two nodes called 'Promoters'. One at the root and one nested inside a 'Partners' child (preferred). I will remove the top level node when I get the nested node working.
Here is the data structure:
"Partners" : {
"Acts" : [hidden],
"Promoters" : [ null, {
"Cell" : hidden,
"Contact Name" : “hidden”,
"Email" : “hidden”,
"Facebook" : “hidden“,
"Title" : "CHORD Productions"
} ]
},
"Promoters" : {
"chord" : {
"Title" : "Chord Productions"
}
}
This retrieves the data I'm looking for (a list of Titles to populate a picker):
let promotersDB = Database.database().reference().child("Promoters")
promotersDB.observe(.childAdded) { (snapshot) in
let snapshotValue = snapshot.value as! Dictionary<String, String>
let promoterName = snapshotValue["Title"]!
let promoter = PromoterClass()
promoter.promoterName = promoterName
self.promoterArray.append(promoter)
let isSuccess = true
completion(isSuccess)
}
This returns nil:
let promotersDB = Database.database().reference().child("Partners").child("Promoters")
promotersDB.observe(.childAdded) { (snapshot) in
let snapshotValue = snapshot.value as! Dictionary<String, String>
let promoterName = snapshotValue["Title"]!
let promoter = PromoterClass()
promoter.promoterName = promoterName
self.promoterArray.append(promoter)
let isSuccess = true
completion(isSuccess)
}
I'd prefer observeSingleEvent, but this also returns nil:
let promotersDB = Database.database().reference().child("Promoters")
promotersDB.observeSingleEvent(of: .value, with: { (snapshot) in
let snapshotValue = snapshot.value as! Dictionary<String, String>
let promoterName = snapshotValue["Title"]!
let promoter = PromoterClass()
promoter.promoterName = promoterName
self.promoterArray.append(promoter)
let isSuccess = true
completion(isSuccess)
})
The error is:
Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
**I am using force unwrapping for now to be reviewed at a later date after investigating how much of the data integrity can be done with backend rules :)
Any assistance would be greatly appreciated.
I think firebase usually suggests the Fan Out method when dealing with data trees, so you shouldn't nest array like "Promoters" anyways.
You'll also want to identify each of the Promoters by a uid instead of by their name (incase you have to change their name in the system).
So if you want, try to restructure your data like this:
let uid = Database.database().reference().child("Promoters").childByAutoId()
// uid will be some super long string of random letters and numbers, for example like: 1hjK2SCRV2fhCI0Vv3plGMct3mL2
"Promoters" : {
"1hjK2SCRV2fhCI0Vv3plGMct3mL2" : {
"Title" : "Chord Productions"
}
}
And then when you want to query values within that promoter's branch:
let titleRef = Database.database().reference().child("Promoters").child(uid)
titleRef.observeSingleEvent(of: .value) { (snapshot) in
if let dict = snapshot.value as? [String: AnyObject] {
let promoter = PromoterClass()
promoterName = dict["Title"] as? String
promoter.promoterName = promoterName
}
}
Can anyone help me figure out why this code is behaving thusly...
When opening the app for the first time a "User" is created (if it doesn't already exist, which it doesn't the first time) and then the user is saved along with his/her golf "clubs". I get confirmation of the user saved and the clubs saved in the console. HOWEVER, when I close the app and reopen it the user is fetched but the clubs are not. What am I missing here? Let me know if you need/want to see any screen captures beyond this code...
//MARK: Core Data Variables
var user : User!
var userClubs = NSMutableSet()
var currentRound : Round!
var managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext!
func prepareUser() {
let fetchRequest = NSFetchRequest(entityName: "User")
let sortDescriptor = NSSortDescriptor(key: "createdTime", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
if let fetchResults = self.managedObjectContext.executeFetchRequest(fetchRequest, error: nil) as? [User] {
if fetchResults.count > 0 {
self.user = fetchResults[0]
println("First user: \(self.user!.firstName) \(self.user!.lastName)")
let fetchRequestClubs = NSFetchRequest(entityName: "Club")
if let fetchResults2 = self.managedObjectContext.executeFetchRequest(fetchRequestClubs, error: nil) as? [Club] {
if fetchResults2.count > 0 {
println("test: \(fetchResults2[0].type)")
}
}
} else {
println("No user yet")
var newUser : User = NSEntityDescription.insertNewObjectForEntityForName("User", inManagedObjectContext: self.managedObjectContext) as! User
newUser.createdTime = NSDate()
managedObjectContext.save(nil)
var i = 0
println("before array: clubsArray is \(clubsArray.count) clubs long")
var clubs = NSMutableSet.mutableSetValueForKey("clubs")
for newClub in clubsArray {
var club : Club = NSEntityDescription.insertNewObjectForEntityForName("Club", inManagedObjectContext: self.managedObjectContext) as! Club
club.type = clubsArray[i].type as String
club.estimatedMinYardage = clubsArray[i].minDistance as Int
club.estimatedMaxYardage = clubsArray[i].maxDistance as Int
club.lowerBound = clubsArray[i].lowerBound as Int
club.upperBound = clubsArray[i].upperBound as Int
//userClubs.addObject(club)
managedObjectContext.save(nil)
//club.setValue(newUser, forKey: "user")
println("\(club.type)")
i++
}
//user.setValue(userClubs, forKey: "clubs")
prepareUser()
}
}
}
Here's the console output from the first run:
No user yet
before array: clubsArray is 17 clubs long
Putter
LW
SW
PW
9i
8i
7i
6i
5i
5W
... [the rest of the clubs]
First user: Your Name
test: 7i
And from the second run after closing and reopening the app:
First user: Your Name
Bloody hell. I was trying to set 1 of the 17 instances of the Club class to a value that was less than it's minimum value allowed in the data model. If anyone else is having a similar issue check your min/max and default in addition to what #Tom-Harrington suggested in the comments of the original question. Dunno if Apple could get some kind of warning for this kind of thing into future versions of XCode.