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"]
Related
I've spend hours looking at identical questions but none of the answers I've found are helping this issue. Simple app retrieves data from Firebase Database and passes to another view controller from the tableview. The main data will pass through but I can't edit the information without an identifying "key" which I tried to set as childByAutoID() but then changed to a timestamp. Regardless of the method, all I get is the entries info not the actual key itself.
func loadData() {
self.itemList.removeAll()
let ref = FIRDatabase.database().reference()
ref.child(userID!).child("MyStuff").observeSingleEvent(of: .value, with: { (snapshot) in
if let todoDict = snapshot.value as? [String:AnyObject] {
for (_,todoElement) in todoDict {
let todo = TheItems()
todo.itemName = todoElement["itemName"] as? String
todo.itemExpires = todoElement["itemExpires"] as? String
todo.itemType = todoElement["itemType"] as? String
self.itemList.append(todo)
print (snapshot.key);
}
}
self.tableView.reloadData()
}) { (error) in
print(error.localizedDescription)
}
}
If your data looks like this:
Uid: {
MyStuff: {
AutoID: {
itemName: “Apocalypse”,
itemExpires: “December 21, 2012”,
itemType: “Catastrophic”
}
}
}
Then I would query like this:
ref.child(userID!).child("MyStuff").observeSingleEvent(of: .value, with: { (snapshot) in
for child in snapshot.children {
let child = child as? DataSnapshot
let key = child?.key as? String
if let todoElement = child?.value as? [String: Any] {
let todo = TheItems()
todo.itemName = todoElement["itemName"] as? String
todo.itemExpires = todoElement["itemExpires"] as? String
todo.itemType = todoElement["itemType"] as? String
self.itemList.append(todo)
self.tableView.reloadData()
}
}
})
Additionally, like I said in my comment you can just upload the key with the data if you’re using .updateChildValues(). Example:
let key = ref.child("userID!").childByAutoId().key
let feed = ["key": key,
“itemName”: itemName] as [String: Any]
let post = ["\(key)" : feed]
ref.child("userID").child("MyStuff").updateChildValues(post) // might want a completionBlock
Then you can get the key the same way you are getting the rest of the values. So your new data would look like this:
Uid: {
MyStuff: {
AutoID: {
itemName: “Apocalypse”,
itemExpires: “December 21, 2012”,
itemType: “Catastrophic”,
key: “autoID”
}
}
}
The key you are trying to look for is located in the iterator of your for loop
Inside your if-let, try to do this:
for (key,todoElement) in todoDict {
print(key) // this is your childByAutoId key
}
This should solve the problem. Otherwise show us a screen of your database structure
I have an issue with my least favourite part in Firebase. I want to pull a post from user's following list (every user has one and only one post). First, I created a completion handler to get a list of all followers from Firebase and store it in userArray array of strings:
func GetUsersInFollowing(completion: #escaping (Bool) -> ()) {
ref.child("following").queryOrdered(byChild: FIRAuth.auth()!.currentUser!.uid).observeSingleEvent(of: .value, with: { (snapshot) in
for group in snapshot.children {
self.userArray.append((group as AnyObject).key)
}
completion(true)
})
}
Now the plan is to pull a post from every element of userArray.
Here is where the problem starts. I call CreatePosts() immediately after GetUsersInFollowing() completes.
func CreatePosts() {
for x in userArray {
var thePost = Post()
print("1")
self.ref.child("users").child(x).observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
thePost.fullName = value?["fullname"] as? String ?? ""
thePost.username = value?["username"] as? String ?? ""
thePost.profileImageURL = value?["photourl"] as? String ?? ""
print("2")
})
self.ref.child("posts").child(x).observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
thePost.description = value?["description"] as? String ?? ""
thePost.info = value?["location"] as? String ?? ""
thePost.postImageURL = value?["photoURL"] as? String ?? ""
thePost.timePost = value?["timestamp"] as? NSDate
thePost.upVotes = value?["upvotes"] as? Int ?? 0
})
self.postArray.append(thePost)
self.tableView.reloadData()
}
}
Everything looks ok to me, but it surely isn't. Here's how I create cells:
func configureCell(post: Post) {
self.post = post
self.username.text = post.username
self.profileImage = post.profileImageURL
print("3")
self.fullname.text = post.fullName
self.timestamp.text = post.timePost
self.upvotes.text = post.upVotes
self.location.text = post.location
self.descriptionText.text = post.description
}
The output in the console varies, but usually I get:
1
1
3
3
2
2
The idea is to first retrieve all data from Firebase, add it to post object, append the object to the array and then create cell for that object with data downloaded. Cell is already created even though data is not retrieved. I think that is the problem. Thank you, every suggestion is appreciated.
You need to inner query for combining both user profile data and post data.
Like this -
func CreatePosts() {
//Using userPostArrayObjFetched as a counter to check the number of data fetched.
//Remove this code, if you don't want to wait till all the user data is fetched.
var userPostArrayObjFetched = 0
for (index,userID) in userArray.enumerated() {
print("1" + userID)
self.ref.child("users").child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
var thePost = Post()
let value = snapshot.value as? NSDictionary
thePost.fullName = value?["fullname"] as? String ?? ""
thePost.username = value?["username"] as? String ?? ""
thePost.profileImageURL = value?["photourl"] as? String ?? ""
print("2" + userID)
self.ref.child("posts").child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
thePost.description = value?["description"] as? String ?? ""
thePost.info = value?["location"] as? String ?? ""
thePost.postImageURL = value?["photoURL"] as? String ?? ""
thePost.timePost = value?["timestamp"] as? NSDate
thePost.upVotes = value?["upvotes"] as? Int ?? 0
print("3" + userID)
self.postArray.append(thePost)
// Uncomment if you want to reload data as fetched from Firebase without waiting for all the data to be fetched.
// self.tableView.reloadData()
userPostArrayObjFetched += 1
if userPostArrayObjFetched == userArray.count{
self.tableView.reloadData()
}
})
})
}
}
I need to make multiple observations, but I don't know how.
Here is my database structure:
"Posts" : {
"f934f8j3f8" : {
"data" : "",
"date" : "",
"userid" : ""
}
},
"Users" : {
"BusWttqaf9bWP224EQ6lOEJezLO2" : {
"Country" : "",
"DOB" : "",
"Posts" : {
"f934f8j3f8" : true
},
"Profilepic" : "",
"name" : "",
"phonenumber" : ""
}
I want to observe the posts and I write the code and it works great, but I also want to get the name of the user who posted this post but when I wrote save the name and use it it gives me null. Here is my code.
DataServices.ds.REF_POSTS.queryOrderedByKey().observe(.value,
with: { (snapshot) in
self.posts = []
if let snapshot = snapshot.children.allObjects as? [FIRDataSnapshot] {
for snap in snapshot {
if let postsDict = snap.value as? Dictionary<String, AnyObject> {
let key = snap.key
let userID = "BusWttqaf9bWP224EQ6lOEJezLO2"
DataServices.ds.REF_USERS.child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let postusername = value?["name"] as? String ?? ""
})
print(" ------ User name : \(postusername) ------")
})
print(" ------ User name 2 : \(postusername) ------")
let post = Posts(postKey: key, postData: postsDict)
self.posts.append(post)
The first print statement prints the username, but the second one prints nothing.
Thanks in advance.
Firebase is asynchronous so you can't operate on a variable until Firebase populates it within it's closure. Additionally code is faster than the internet so any statements following a closure will occur before the statements within the closure.
The flow would be as follows
Query for the post {
get the user id from the post inside this closure
query for the user info {
create the post inside this second closure
append the data to the array inside this second closure
reload tableview etc inside this second closure
}
}
Something like this edited code
self.posts = []
myPostsRef.queryOrderedByKey().observe(.value, with: { (snapshot) in
if let snapshot = snapshot.children.allObjects as? [FIRDataSnapshot] {
for snap in snapshot {
if let postsDict = snap.value as? Dictionary<String, AnyObject> {
let key = snap.key
let userID = "BusWttqaf9bWP224EQ6lOEJezLO2"
myUsersRef.child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let userName = value?["name"] as? String ?? ""
let post = Posts(postKey: key, postData: postsDict, name:userName)
self.posts.append(post)
})
}
}
}
})
You're not using the postusername inside the closure so I added that to the Posts initialization.
Also, the self.posts = [] is going to reset the posts array any time there's a change in the posts node - you may want to consider loading the array first, and then watch for adds, changes, or deletes and just update the posts array with single changes instead of reloading the entire array each time.
Edit:
A comment was made about the data not being available outside the loop. Here is a very simplified and tested version. Clicking button one populates the array from Firebase with a series of strings, clicking button 2 prints the array.
var posts = [String]()
func doButton1Action() {
let postsRef = ref.child("posts")
self.posts = []
postsRef.observe(.value, with: { (snapshot) in
if let snapshot = snapshot.children.allObjects as? [FIRDataSnapshot] {
for snap in snapshot {
let value = snap.value as! String
self.posts.append(value)
}
}
})
}
func doButton2Action() {
print(posts)
}
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()
})
}
func generateDataForRecents() {
if URLArrayStringThisSeason.count == 0 {
self.activityIndicator2.isHidden = false
self.activityIndicator2.startAnimating()
}
let databaseRef = FIRDatabase.database().reference()
databaseRef.child("palettes").queryLimited(toFirst: 100).observe(.value, with: { (snapshot) in
if let snapDict = snapshot.value as? [String:AnyObject]{
for each in snapDict as [String:AnyObject]{
let URL = each.value["URL"] as! String
self.URLArrayStringRecents.append(URL)
//print(self.URLArrayString.count)
//print(snapshot)
//let pictureTitle = each.value["title"] as! String
print(self.URLArrayStringRecents.count)
}
}
self.whatsNewCollectionView?.reloadData() //Reloads data after the number and all the URLs are fetched
self.activityIndicator2.stopAnimating()
self.activityIndicator2.isHidden = true
})
}
The following code does a retrieval of data each time the function is called, or when a new data is added.
This is extremely useful when the app is first started up or closed and then restarted. However, when the app is running, whenever a new entry is added, the code seemed to run again and thus appending twice the amount of new data.
For example, when there are already 15 entries identified and then suddenly a new entry is added, the array of the URL would contain 15+16 thus amounting to a total of 31.
How do I make it such that the new data is added to the array instead of adding the entire snapshot in?
You do that by listening for .childAdded events, instead of listening for .value:
var query = databaseRef.child("palettes").queryLimited(toFirst: 100)
query.observe(.childAdded, with: { (snapshot) in
let URL = snapshot.childSnapshot(forPath/: "URL").value as! String
self.URLArrayStringRecents.append(URL)
}
Since you have a limit-query, adding a 101st item means that one item will be removed from the view. So you'll want to handle .childRemoved too:
query.observe(.childRemoved, with: { (snapshot) in
// TODO: remove the item from snapshot.key from the araay
})
I recommend that you spend some time in the relevant documentation on handling child events before continuing.
Please check below method. I have use this method not getting any duplicate entry.
func getallNotes()
{
let firebaseNotesString: String = Firebase_notes.URL
let firebaseNotes = FIRDatabase.database().referenceFromURL(firebaseNotesString).child(email)
firebaseNotes.observeEventType(.Value, withBlock: { snapshot in
if snapshot.childSnapshotForPath("Category").hasChildren()
{
let child = snapshot.children
self.arrNotes = NSMutableArray()
self.arrDictKeys = NSMutableArray()
for itemsz in child
{
let childz = itemsz as! FIRDataSnapshot
let AcqChildKey : String = childz.key
if AcqChildKey == AcqIdGlobal
{
if (childz.hasChildren() == true)
{
let dictChild = childz.value as! NSMutableDictionary
self.arrDictKeys = NSMutableArray(array: dictChild.allKeys)
for i in 0..<self.arrDictKeys.count
{
let _key = self.arrDictKeys.objectAtIndex(i).description()
print(_key)
let dictData : NSMutableDictionary = NSMutableDictionary(dictionary: (dictChild.valueForKey(_key)?.mutableCopy())! as! [NSObject : AnyObject])
dictData.setObject(_key, forKey: "notesId")
self.arrNotes.addObject(dictData)
}
}
}
}
self.tableviewNote.reloadData()
}
})
}
As for the query for removed child,
query.observe(.childRemoved, with: { (snapshot) in
print(snapshot)
let URL = snapshot.childSnapshot(forPath: "URL").value as! String
self.URLArrayStringThisSeason = self.URLArrayStringThisSeason.filter() {$0 != URL}
self.thisSeasonCollectionView.reloadData()
})
it will obtain the URL of the removed child and then update the array accordingly.