Trying to get an array of child keys from Firebase
func getWavePosts() {
let wavePostRoot = Database.database().reference().child("waves_posts/\(self.waveLabel!)/")
wavePostRoot.observe(.value , with: {snapshot in
var tempKeys = [String]()
for child in snapshot.children {
let snap = child as! DataSnapshot
let key = snap.key {
tempKeys.append(key as String)
}
}
self.tempNames = tempKeys
})
}
I've done this for values before but not keys, the append line is the one that is flagged. Inserting a line below the key initialization changes the error to "Generic parameter 'Element' could not be inferred". Any help would be much appreciated!
--------- edit without for loop ---------
let wavePostRoot = Database.database().reference().child("waves_posts/\(self.waveLabel!)/")
wavePostRoot.observe(.value , with: {snapshot in
var tempKeys = [String]()
self.tempNames.append(snapshot.key)
You want to do optional-binding but you forgot to if keyword. Also I think that you want to check if snap.key is of type String
if let string = snap.key as? String {
tempKeys.append(string)
}
Related
I need to show these data in a table view, but they have been on the table view in mixing order. How can I put them in the same order as in the database. Please help, I will deeply appreciated.
First image shows my iPhone screen after running the project, second one is the database. I want them exact order as in the database.
I hope periods objects look like this:
struct PeriodItem {
let key: String
let periodEnd: String
let periodName: String
let periodStart: String
let ref: FIRDatabaseReference?
init(periodEnd: String, periodName: String, periodStart: String, key: String = "") {
self.key = key
self.periodEnd = periodEnd
self.periodName = periodName
self.periodStart = periodStart
self.ref = nil
}
init(snapshot: FIRDataSnapshot) {
key = snapshot.key
let snapshotValue = snapshot.value as! [String: AnyObject]
periodEnd = snapshotValue["periodEnd"] as! String
periodName = snapshotValue["periodName"] as! String
periodStart = snapshotValue["periodStart"] as! String
ref = snapshot.ref
}
func toAnyObject() -> Any {
return [
"periodEnd": periodEnd,
"periodName": periodName,
"periodStart": periodStart,
"key": key
]
}
}
So
When you fill your array of Periods fully, just use sorting:
// periods - array of objects from firebase database
let yourTableViewPeriodsArray = periods.sorted(by: { $0.key < $1.key }) // maybe ">" instead of "<"
Then:
DispatchQueue.main.async {
self.tableView.reloadData()
}
Hope it helps.
So I am currently trying to take data from my Firebase database and set it as its own variable, but the child for each chart is a specific date and time (yy.mm.dd.h.m.s). So i have an array storing all the dates I need, but i cant reference them when calling my snapshot. I've tried these two methods which throw the error "(child:) Must be a non-empty string and not contain '.' '#' '$' '[' or ']''"
var postCollection = [170802120618, 170802101427] //yy.mm.dd.hh.mm.ss
ref.child("users").child(uid!).child("Posts").child(self.postCollection[indexPath.row]).observe(.value, with: { (snapshot) in
for item in snapshot.children{
let snapshotValue = snapshot.value as? NSDictionary
let firstNameSnap = snapshotValue?["First Name"] as? String ?? ""
currentCell.nameLabel.text = firstNameSnap
}
})
and
var postCollection = [170802120618, 170802101427] //yy.mm.dd.hh.mm.ss
let selection = self.postCollection[indexPath.row]
ref.child("users").child(uid!).child("Posts").child(self.postCollection[indexPath).observe(.value, with: { (snapshot) in
for item in snapshot.children{
let snapshotValue = snapshot.value as? NSDictionary
let firstNameSnap = snapshotValue?["First Name"] as? String ?? ""
currentCell.nameLabel.text = firstNameSnap
}
})
And the Database chart being roughly:
FIR{
users{
uid{
username: UserName
Posts{
170802120618{
First Name: first
}
}
}
}
}
Right. You want the child key to be an autogenerated hashvalue. You can create these by using childByAutoId(). Also if I were you, I would just store that dates as string and parse those as needed. Something below would be an example:
Posts {
-Kebfdajksthm {
first_name: "first",
post_date: "yymmddhhmmss"
}
}
Try This
var post = [String]()
ref.observe(.value, with: { (snapshot) in
for item in snapshot.children{
self.post.append((item as AnyObject).key)
}
})
Then you print "post" and you will get ["170802120618", "170802101427"]
I am trying to print array from the firebase. Actually if we tap a medication in a list(tableviewcontroller), it will show its specfic dosages. I got stucked to retrieve the dosages list. Here is my code to get data from firebase. Any help is appreciated. Thanks in advance. My firebase structure looks like this.. firebase img
func loadDataFromFirebase() {
databaseRef = FIRDatabase.database().reference().child("medication")
databaseRef.observeEventType(.Value, withBlock: { snapshot in
for item in snapshot.children{
FIRDatabase.database().reference().child("medication").child("options").observeEventType(.Value, withBlock: {snapshot in
print(snapshot.value)
})
}
})
You should take a look on firebase documentation https://firebase.google.com/docs/database/ios/read-and-write
but if I'm understanding your idea, you probably has a model class for your medications. So, to retrieve your data you should do like this for Swift 3.0:
func loadDataFromFirebase() {
databaseRef = FIRDatabase.database().reference().child("medication")
databaseRef.observe(.value, with: { (snapshot) in
for item in snapshot.children{
// here you have the objects that contains your medications
let value = item.value as? NSDictionary
let name = value?["name"] as? String ?? ""
let dossage = value?["dossage"] as? String ?? ""
let type = value?["type"] as? String ?? ""
let options = value?["options"] as? [String] ?? ""
let medication = Medication(name: name, dossage: dossage, type: type, options: options)
// now you populate your medications array
yourArrayOfMedications.append(medication)
}
yourTableView.reloadData()
})
}
Now that you have your array with all your medications, you just need to populate your tableView with this medications. When someone press an item on table you can just call prepareForSegue: and send your yourArrayOfMedications[indexPath.row].options to the next view
The solution is same as above but with a small change.
func loadDataFromFirebase() {
databaseRef = FIRDatabase.database().reference().child("medication")
databaseRef.observe(.value, with: { (snapshot) in
for item in snapshot.children{
// here you have the objects that contains your medications
let value = item.value as? NSDictionary
let name = value?["name"] as? String ?? ""
let dossage = value?["dossage"] as? String ?? ""
let type = value?["type"] as? String ?? ""
let options = value?["options"] as? [String : String] ?? [:]
print(options["first"]) // -> this will print 100 as per your image
// Similarly you can add do whatever you want with this data
let medication = Medication(name: name, dossage: dossage, type: type, options: options)
// now you populate your medications array
yourArrayOfMedications.append(medication)
}
yourTableView.reloadData()
})
}
I'm new to firebase and I have such structure of my firebase project
I want to get all objects, that "Interested" value is equal to "men"
I wrote such code, to get all object sorted by interes value:
let thisUserRef = URL_BASE.childByAppendingPath("profile")
thisUserRef.queryOrderedByChild("Interest")
.observeEventType(.Value, withBlock: { snapshot in
if let UserInterest = snapshot.value!["Interest"] as? String {
print (snapshot.key)
}
}
But I receive nil.
you need to loop through all the key-value profiles
if let allProfiles = snapshot.value as? [String:AnyObject] {
for (_,profile) in allProfiles {
print(profile);
let userInterest = profile["Interest"]
}
}
Here _ is the key that is in the format KYXA-random string and profile will be the element for that key.
Edit:
There is querying for child values as per the docs.
Try thisUserRef.queryOrderedByChild("Interest").equalTo("men") and then using the inner loop that i specified in the answer
This is a basic query in Firebase. (Updated for Swift 3, Firebase 4)
let profileRef = self.ref.child("profile")
profileRef.queryOrdered(byChild: "Interest").queryEqual(toValue: "men")
profileRef.observeSingleEvent(of: .value, with: { snapshot in
for child in snapshot.children {
let dict = child as! [String: Any]
let name = dict["Name"] as! String
print(name)
}
})
The legacy documentation from Firebase really outlines how to work with queries: find it here
Legacy Firebase Queries
The new documentation is pretty thin.
Oh, just to point out the variable; thisUserNode should probably be profileRef as that's what you are actually query'ing.
I have a "flatened" Firebase structure and trying to retrieve a dictionary of values from a "secondary" database member. In other words, I have a conversation which has a "to" cell which has the key to a business listing. With this key, I'm trying to retrieve the business listing and its children (url, description, title). For some reason, I can print the snapshot2.value and it responds with the expected value, but I can't pass it to my class initialization.
DataService.ds.REF_CONVOS.observeEventType(.Value, withBlock: {snapshot in
self.convoListings.removeAll()
self.convoListings = []
//Data parsing from Firebase. The goal is to breakdown the data received and store in a local model.
if let snapshots = snapshot.children.allObjects as? [FDataSnapshot] {
for snap in snapshots {
for convo in userConvos {
// Going into the children of the main object for the conversations.
//print("\(snap)")
if convo == snap.key {
//print(snap.value)
print(snap.value)
if let businessDict = snap.value as? Dictionary<String, AnyObject> {
businessName.removeAll()
let test = businessDict["to"] as? String
DataService.ds.REF_BusinessListing.childByAppendingPath(test).childByAppendingPath("title/").observeSingleEventOfType(.Value, withBlock: { snapshot2 in
print(snapshot2.value)
})
let key = snap.key
let post = ConvoListing(convoKey: key, dictionary: businessDict, businessName: self.test2)
self.convoListings.append(post)
}
}
}
}
}
self.tableView.reloadData()
})
Your nesting seems of:
DataService.ds.REF_BusinessListing.childByAppendingPath(test).childByAppendingPath("title/").observeSingleEventOfType(.Value, withBlock: { snapshot2 in
print(snapshot2.value)
})
let key = snap.key
let post = ConvoListing(convoKey: key, dictionary: businessDict, businessName: self.test2)
self.convoListings.append(post)
Keep in mind the observeSingleEventOfType loads the data asynchronously. For this reason, if you have code that needs the value that you loaded, you need to put that code in the block:
DataService.ds.REF_BusinessListing.childByAppendingPath(test).childByAppendingPath("title/").observeSingleEventOfType(.Value, withBlock: { snapshot2 in
print(snapshot2.value)
let key = snap.key
let post = ConvoListing(convoKey: key, dictionary: businessDict, businessName: self.test2)
self.convoListings.append(post)
})