Im currently retrieving data from firebase the data is put inside an NSObject and then a completion block. The item inside of the completion block is store as a variable userBinfos. Variable userBinfos only work inside of the completion block i want to use this outside of the completion
var userBinfos = userObject()
override func viewDidLoad() {
super.viewDidLoad()
userBinfo { (user) in
self.userBinfos = user
}
//I want to use to variable here but it does not work
print(self.userBinfos.email)
}
func userBinfo(completion: (userObject) -> ()) {
let dbFir = FIRDatabase.database().reference()
let firRef = dbFir.child("frontEnd/users/\(userId)")
firRef.observeEventType(.Value, withBlock: { snapshot in
let userDict = snapshot.value as! [String: AnyObject]
self.name.text = userDict["firstname"] as? String
self.userBio.text = userDict["userBio"] as! String
var user = userObject()
user.firstName = userDict["firstname"]
user.lastName = userDict["lastname"]
user.email = userDict["email"]
user.profileImageUrl = userDict["profileImageUrl"]
user.userBio = userDict["firstname"]
user.userId = userDict["firstname"]
dispatch_async(dispatch_get_main_queue(), {
completion(user)
})
}) { (error) in
print(error)
}
}
The entire purpose of the completion parameter of userBinfo is to provide a mechanism for being informed when the asynchronous observeEventType is called. So put code contingent upon the completion of that asynchronous method inside the userBinfo { user in ... } closure.
And if part of the UI doesn't make sense until that asynchronous completion closure is called, then have viewDidLoad configure the UI to make that explicit (perhaps show a UIActivityIndicatorView or whatever) and then remove that stuff inside the completion handler.
override func viewDidLoad() {
super.viewDidLoad()
// do whatever you want to let the user know that something asynchronous
// is happening, e.g. add a spinning `UIActivityIndicatorView` or whatever
userBinfo { user in
self.userBinfos = user
// Update the UI here, including removing anything we presented to let
// the user know that the asynchronous process was underway. If you were
// dealing with UITableView`, you'd call `tableView.reloadData()` here.
}
// but not here
}
Related
I'm calling a Firestore query that does come back, but I need to ensure completion before moving on with the rest of the code. So I need a completion handler...but for the life of me I can't seem to code it.
// get user info from db
func getUser() async {
self.db.collection("userSetting").getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let userTrust = document.data()["userTrust"] as! String
let userGrade = document.data()["userGrade"] as! String
let userDisclaimer = document.data()["userDisclaimer"] as! String
var row = [String]()
row.append(userTrust)
row.append(userGrade)
row.append(userDisclaimer)
self.userArray.append(row)
// set google firebase analytics user info
self.userTrustInfo = userTrust
self.userGradeInfo = userGrade
}
}
}
}
Called by:
internal func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
FirebaseApp.configure()
db = Firestore.firestore()
Database.database().isPersistenceEnabled = true
Task {
do {
let userInfo = await getUser()
}
} return true }
I used a Task as didFinishLauncingWithOptions is synchronous and not asynchronous
However, the getUser() still isn't completed before didFinishLauncingWithOptions moves on.
I need the data from getUser as the very next step uses the data in the array, and without it I get an 'out of bounds exception' as the array is still empty.
Also tried using dispatch group within the func getUser(). Again with no joy.
Finally tried a completion handler:
func getUser(completion: #escaping (Bool) -> Void) {
self.db.collection("userSetting").getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let userTrust = document.data()["userTrust"] as! String
let userGrade = document.data()["userGrade"] as! String
let userDisclaimer = document.data()["userDisclaimer"] as! String
var row = [String]()
row.append(userTrust)
row.append(userGrade)
row.append(userDisclaimer)
self.userArray.append(row)
// set google firebase analytics user info
self.userTrustInfo = userTrust
self.userGradeInfo = userGrade
completion(true)
}
}
}
}
Nothing works. The getUser call isn't completed before the code moves on. Can someone please help. I've searched multiple times, looked at all linked answers but I can not make this work.I'm clearly missing something easy, please help
read this post: Waiting for data to be loaded on app startup.
It explains why you should never wait for data before returning from
function application(_:didFinishLaunchingWithOptions).
To achieve what you need, you could use your first ViewController as a sort of splashscreen (that only shows an image or an activity indicator) and call the function getUser(completion:) in the viewDidLoad() method the ViewController.
Example:
class FirstViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
MyFirestoreDatabaseManager.shared.getUser() { success in
if success {
//TODO: Navigate to another ViewController
} else {
//TODO: Show an error
}
}
}
}
Where obviously MyFirestoreDatabaseManager.shared is the object on which you defined the getUser(completion:) method.
(In your example, I think that you defined that function in the AppDelegate. In that case, you should mark your getUser(completion:) method and all related variables as static. Then replace MyFirestoreDatabaseManager.shared with AppDelegate).
Not 100% sure what you would like to accomplish as I can't see all your code, but try something similar to this, replacing Objects for what you are trying to return from the documents.
You don't want your user's data spread across multiple documents. With Firebase you pay for every document you have to get. Ideally you want all your user's settings within one firebase document. Then create a UserInfo struct that you can decode to using the library CodeableFirebase or the decoder of your choice.
// Create user struct
struct UserInfo: Codable {
var userId: String
var userTrust: String
var userGrade: String
var userDisclaimer: String
}
// get user info from db and decode using CodableFirebase
func getUser() async throws -> UserInfo {
let doc = try await self.db.collection("users").document("userIdHere")
let userInfo = try FirestoreDecoder().decode(UserInfo.self, from: doc.data())
return UserInfo
}
Then you can do this...
Task {
do {
let userInfo = try await getUser()
let userTrust = userInfo.userTrust
let userGrade = userInfo.userGrade
let userDisclaimer = userInfo.userDisclaimer
}
}
I'm getting info from an API using the following function where I pass in a string of a word. Sometimes the word doesn't available in the API if it doesn't available I generate a new word and try that one.
The problem is because this is an asynchronous function when I launch the page where the value from the API appears it is sometimes empty because the function is still running in the background trying to generate a word that exists in the API.
How can I make sure the page launches only when the data been received from the api ?
static func wordDefin (word : String, completion: #escaping (_ def: String )->(String)) {
let wordEncoded = word.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)
let uri = URL(string:"https://dictapi.lexicala.com/search?source=global&language=he&morph=false&text=" + wordEncoded! )
if let unwrappedURL = uri {
var request = URLRequest(url: unwrappedURL);request.addValue("Basic bmV0YXlhbWluOk5ldGF5YW1pbjg5Kg==", forHTTPHeaderField: "Authorization")
let dataTask = URLSession.shared.dataTask(with: request) { (data, response, error) in
do {
if let data = data {
let decoder = JSONDecoder()
let empty = try decoder.decode(Empty.self, from: data)
if (empty.results?.isEmpty)!{
print("oops looks like the word :" + word)
game.wordsList.removeAll(where: { ($0) == game.word })
game.floffWords.removeAll(where: { ($0) == game.word })
helper.newGame()
} else {
let definition = empty.results?[0].senses?[0].definition
_ = completion(definition ?? "test")
return
}
}
}
catch {
print("connection")
print(error)
}
}
dataTask.resume()
}
}
You can't stop a view controller from "launching" itself (except not to push/present/show it at all). Once you push/present/show it, its lifecycle cannot—and should not—be stopped. Therefore, it's your responsibility to load the appropriate UI for the "loading state", which may be a blank view controller with a loading spinner. You can do this however you want, including loading the full UI with .isHidden = true set for all view objects. The idea is to do as much pre-loading of the UI as possible while the database is working in the background so that when the data is ready, you can display the full UI with as little work as possible.
What I'd suggest is after you've loaded the UI in its "loading" configuration, download the data as the final step in your flow and use a completion handler to finish the task:
override func viewDidLoad() {
super.viewDidLoad()
loadData { (result) in
// load full UI
}
}
Your data method may look something like this:
private func loadData(completion: #escaping (_ result: Result) -> Void) {
...
}
EDIT
Consider creating a data manager that operates along the following lines. Because the data manager is a class (a reference type), when you pass it forward to other view controllers, they all point to the same instance of the manager. Therefore, changes that any of the view controllers make to it are seen by the other view controllers. That means when you push a new view controller and it's time to update a label, access it from the data property. And if it's not ready, wait for the data manager to notify the view controller when it is ready.
class GameDataManager {
// stores game properties
// updates game properties
// does all thing game data
var score = 0
var word: String?
}
class MainViewController: UIViewController {
let data = GameDataManager()
override func viewDidLoad() {
super.viewDidLoad()
// when you push to another view controller, point it to the data manager
let someVC = SomeOtherViewController()
someVC.data = data
}
}
class SomeOtherViewController: UIViewController {
var data: GameDataManager?
override func viewDidLoad() {
super.viewDidLoad()
if let word = data?.word {
print(word)
}
}
}
class AnyViewController: UIViewController {
var data: GameDataManager?
}
In my iOS app, I have two Firebase-related functions that I want to call within viewDidLoad(). The first picks a random child with .queryOrderedByKey() and outputs the child's key as a string. The second uses that key and observeEventType to retrieve child values and store it in a dict. When I trigger these functions with a button in my UI, they work as expected.
However, when I put both functions inside viewDidLoad(), I get this error:
Terminating app due to uncaught exception 'InvalidPathValidation', reason: '(child:) Must be a non-empty string and not contain '.' '#' '$' '[' or ']''
The offending line of code is in my AppDelegate.swift, highlighted in red:
class AppDelegate: UIResponder, UIApplicationDelegate, UITextFieldDelegate
When I comment out the second function and leave the first inside viewDidLoad, the app loads fine, and subsequent calls of both functions (triggered by the button action) work as expected.
I added a line at the end of the first function to print out the URL string, and it doesn't have any offending characters: https://mydomain.firebaseio.com/myStuff/-KO_iaQNa-bIZpqe5xlg
I also added a line between the functions in viewDidLoad to hard-code the string, and I ran into the same InvalidPathException issue.
Here is my viewDidLoad() func:
override func viewDidLoad() {
super.viewDidLoad()
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(ViewController.dismissKeyboard))
view.addGestureRecognizer(tap)
pickRandomChild()
getChildValues()
}
Here is the first function:
func pickRandomChild () -> String {
var movieCount = 0
movieRef.queryOrderedByKey().observeEventType(.Value, withBlock: { (snapshot) in
for movie in snapshot.children {
let movies = movie as! FIRDataSnapshot
movieCount = Int(movies.childrenCount)
movieIDArray.append(movies.key)
}
repeat {
randomIndex = Int(arc4random_uniform(UInt32(movieCount)))
} while excludeIndex.contains(randomIndex)
movieToGuess = movieIDArray[randomIndex]
excludeIndex.append(randomIndex)
if excludeIndex.count == movieIDArray.count {
excludeIndex = [Int]()
}
let arrayLength = movieIDArray.count
})
return movieToGuess
}
Here is the second function:
func getChildValues() -> [String : AnyObject] {
let movieToGuessRef = movieRef.ref.child(movieToGuess)
movieToGuessRef.observeEventType(.Value, withBlock: { (snapshot) in
movieDict = snapshot.value as! [String : AnyObject]
var plot = movieDict["plot"] as! String
self.moviePlot.text = plot
movieValue = movieDict["points"] as! Int
})
return movieDict
)
And for good measure, here's the relevant portion of my AppDelegate.swift:
import UIKit
import Firebase
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UITextFieldDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
FIRApp.configure()
return true
}
I'm guessing Swift is executing the code not in the order I expect. Does Swift not automatically wait for the first function to finish before running the second? If that's the case, why does this pairing work elsewhere in the app but not in viewDidLoad?
Edit: The issue is that closures are not called in order.
I'm not sure what your pickRandomChild() and getChildValues() methods are, so please post them as well, but the way I fixed this type issue was by sending the data through a closure that can be called in your ViewController.
For example when I wanted to grab data for a Full Name and Industry I used this. This method takes a Firebase User, and contains a closure that will be called upon completion. This was defined in a class specifically for pulling data.
func grabDataDict(fromUser user: FIRUser, completion: (data: [String: String]) -> ()) {
var myData = [String: String]()
let uid = user.uid
let ref = Constants.References.users.child(uid)
ref.observeEventType(.Value) { (snapshot, error) in
if error != nil {
ErrorHandling.defaultErrorHandler(NSError.init(coder: NSCoder())!)
return
}
let fullName = snapshot.value!["fullName"] as! String
let industry = snapshot.value!["industry"] as! String
myData["fullName"] = fullName
myData["industry"] = industry
completion(data: myData)
}
}
Then I defined an empty array of strings in the Viewcontroller and called the method, setting the variable to my data inside the closure.
messages.grabRecentSenderIds(fromUser: currentUser!) { (userIds) in
self.userIds = userIds
print(self.userIds)
}
If you post your methods, however I can help you with those specifically.
Edit: Fixed Methods
1.
func pickRandomChild (completion: (movieToGuess: String) -> ()) {
var movieCount = 0
movieRef.queryOrderedByKey().observeEventType(.Value, withBlock: { (snapshot) in
for movie in snapshot.children {
let movies = movie as! FIRDataSnapshot
movieCount = Int(movies.childrenCount)
movieIDArray.append(movies.key)
}
repeat {
randomIndex = Int(arc4random_uniform(UInt32(movieCount)))
} while excludeIndex.contains(randomIndex)
movieToGuess = movieIDArray[randomIndex]
excludeIndex.append(randomIndex)
if excludeIndex.count == movieIDArray.count {
excludeIndex = [Int]()
}
let arrayLength = movieIDArray.count
// Put whatever you want to return here.
completion(movieToGuess)
})
}
2.
func getChildValues(completion: (movieDict: [String: AnyObject]) -> ()) {
let movieToGuessRef = movieRef.ref.child(movieToGuess)
movieToGuessRef.observeEventType(.Value, withBlock: { (snapshot) in
movieDict = snapshot.value as! [String : AnyObject]
var plot = movieDict["plot"] as! String
self.moviePlot.text = plot
movieValue = movieDict["points"] as! Int
// Put whatever you want to return here.
completion(movieDict)
})
}
Define these methods in some model class, and when you call them in your viewcontroller, you should be able to set your View Controller variables to movieDict and movieToGuess inside each closure. I made these in playground, so let me know if you get any errors.
Your functions pickRandomChild() and getChildValues() are asynchronous, therefore they only get executed at a later stage, so if getChildValues() needs the result of pickRandomChild(), it should be called in pickRandomChild()'s completion handler / delegate callback instead, because when one of those are called it is guaranteed that the function has finished.
It works when you comment out the second function and only trigger it with a button press because there has been enough time between the app loading and you pushing the button for the asynchronous pickRandomChild() to perform it action entirely, allowing getChildValues() to use its returned value for its request.
I'm using HanekeSwift to retrieve cached data and then set it to labels in a swipeView every time the view appears. My code retrieves the data no problem, but because cache.fetch() is asynchronous, when I call my method to update the view, my labels are set to nil. Is there anyway to tell swift to wait until my cached data is retrieved before loading the view?
See code below:
override func viewWillAppear(animated: Bool) {
updateEntries() // updates entries from cache when view appears
}
func updateEntries() {
guard let accessToken = NSUserDefaults.standardUserDefaults().valueForKey("accessToken") as? String else { return }
guard let cachedEntryKey = String(accessToken) + "food_entries.get" as? String else { return }
cache.fetch(key: cachedEntryKey).onSuccess { data in
...
// if successful, set labels in swipeView to data retrieved from cache
...
dispatch_group_leave(dispatchGroup)
} .onFailure { error in
print(error)
...
// if unsuccessful, call servers to retrieve data, set labels in swipeView to that data
...
dispatch_group_leave(dispatchGroup)
}
}
When I step through the above code, it always displays the view and then steps into the cache block. How do I make viewWillAppear() allow updateEntries() to complete and not return out of it until the cache block is executed? Thanks a ton in advance!
Update 1:
The solution below is working pretty well and my calls are made in the correct sequence (my print statement in the notify block executes after the cache retrieval), but my views only update their labels with non-nil values when the server is called. Maybe I'm lumping the wrong code in the notify group?
override func viewWillAppear(animated: Bool) {
self.addProgressHUD()
updateEntries() // updates entries from cache when view appears
}
func updateEntries() {
guard let accessToken = NSUserDefaults.standardUserDefaults().valueForKey("accessToken") as? String else { return }
guard let cachedEntryKey = String(accessToken) + "food_entries.get" as? String else { return }
let dispatchGroup = dispatch_group_create()
dispatch_group_enter(dispatchGroup)
dispatch_group_async(dispatchGroup, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
cache.fetch(key: cachedEntryKey).onSuccess { data in
...
// if successful, set labels in swipeView to data retrieved from cache
...
} .onFailure { error in
print(error)
...
// if unsuccessful, call servers to retrieve data, set labels in swipeView to that data
...
}
}
dispatch_group_notify(dispatchGroup, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
print("Retrieved Data")
self.removeProgressHUD()
}
}
Update 2:
Also, I'm getting this warning in the console when I switch views. I think I'm locking up the main thread with the above code
"This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes. This will cause an exception in a future release."
Note:
enter group before calling asynchronous method
leave group is each of the respective completion/failure handlers
dispatch UI updates in notify block to main queue
Thus:
func updateEntries() {
guard let accessToken = NSUserDefaults.standardUserDefaults().valueForKey("accessToken") as? String else { return }
guard let cachedEntryKey = String(accessToken) + "food_entries.get" as? String else { return }
let group = dispatch_group_create()
dispatch_group_enter(group)
cache.fetch(key: cachedEntryKey).onSuccess { data in
...
// if successful, set labels in swipeView to data retrieved from cache
...
dispatch_group_leave(group)
} .onFailure { error in
print(error)
...
// if unsuccessful, call servers to retrieve data, set labels in swipeView to that data
...
dispatch_group_leave(group)
}
dispatch_group_notify(group, dispatch_get_main_queue()) {
print("Retrieved Data")
self.removeProgressHUD()
}
}
Ok suggestions from everyone helped a ton on this. Think I got it. I need to make sure my cache block isn't blocking the main queue. See code below
EDIT
Thanks to #Rob for helping me make the proper adjustments to make this work
let dispatchGroup = dispatch_group_create()
dispatch_group_enter(dispatchGroup)
cache.fetch(key: cachedEntryKey).onSuccess { data in
...
// if successful, set labels in swipeView to data retrieved from cache
...
dispatch_group_leave(dispatchGroup)
} .onFailure { error in
print(error)
...
// if unsuccessful, call servers to retrieve data, set labels in swipeView to that data
...
dispatch_group_leave(dispatchGroup)
}
dispatch_group_notify(dispatchGroup, dispatch_get_main_queue()) {
print("Retrieved Data")
self.removeProgressHUD()
}
Here's simple example that you can stage a loading screen. I just create a alert view, also you can create your custom loading indicator view instead.
let alert = UIAlertController(title: "", message: "please wait ...", preferredStyle: .alert)
override func viewWillAppear(animated: Bool) {
self.present(alert, animated: true, completion: nil)
updateEntries() // updates entries from cache when view appears
}
func updateEntries() {
guard let accessToken = UserDefaults.standard.value(forKey: "accessToken") as? String,
let cachedEntryKey = (accessToken + "food_entries.get") as? String else {
return
}
cache.fetch(key: cachedEntryKey).onSuccess { data in
...
// update value in your UI
alert.dismiss(animated: true, completion: nil)
...
} .onFailure { error in
print(error)
...
// if unsuccessful, call servers to retrieve data, set labels in swipeView to that data
...
}
}
While I entirely agree with #ozgur about displaying some sort of loading indicator from a UX standpoint, I figured the benefit of learning how to use Grand Central Dispatch (Apple's native solution to asynchronous waiting) might help you in the long-term.
You can use dispatch_groups to wait for a block(s) of code to completely finish running before running a completion handler of some sort.
From Apple's documentation:
A dispatch group is a mechanism for monitoring a set of blocks. Your application can monitor the blocks in the group synchronously or asynchronously depending on your needs. By extension, a group can be useful for synchronizing for code that depends on the completion of other tasks.
[...]
The dispatch group keeps track of how many blocks are outstanding, and GCD retains the group until all its associated blocks complete execution.
Here's an example of dispatch_groups in action:
let dispatchGroup = dispatch_group_create()
dispatch_group_async(dispatchGroup, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
// Run whatever code you need to in here. It will only move to the final
// dispatch_group_notify block once it reaches the end of the block.
}
dispatch_group_notify(dispatchGroup, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
// Code in here only runs once all dispatch_group_async blocks associated
// with the dispatchGroup have finished completely.
}
The great part about dispatch_groups are that they allow you to run multiple asynchronous blocks at the same time and wait for all of them to finish before running the final completion handler. In other words, you can associate as many dispatch_group_async blocks with the dispatchGroup as you want.
If you wanted to go for the loading indicator approach (which you should), you can run code to display the loading indicator, then move into a dispatch_group with a completion handler to remove the loading indicator and load data into view once the dispatch_group completes.
I have a single view of SlackTextViewController which works as a UITableView. I'm switching between "states" using a public String allowing it to read 1 set of data in a certain state and another set of data in another state. The problem is when I switch back and forth to the original state it prints the data 2, 3, 4 times; as many as I go back and forth. I'm loading the data from a Firebase server and I think it may be a Firebase issue. Here is my code...
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
if chatState == "ALL"
{
self.globalChat()
}else if chatState == "LOCAL"
{
self.localChat()
}
}
override func viewDidDisappear(animated: Bool) {
self.messageModels.removeAll()
tableView.reloadData()
ref.removeAllObservers()
}
func chatACTN()
{
if chatState == "ALL"
{
self.viewWillAppear(true)
}else if chatState == "LOCAL"
{
self.viewWillAppear(true)
}
}
func globalChat()
{
self.messageModels.removeAll()
tableView.reloadData()
let globalRef = ref.child("messages")
globalRef.keepSynced(true)
globalRef.queryLimitedToLast(100).observeEventType(.ChildAdded, withBlock: { (snapshot) -> Void in
if snapshot.exists()
{
let names = snapshot.value!["name"] as! String
let bodies = snapshot.value!["body"] as! String
let avatars = snapshot.value!["photo"] as! String
let time = snapshot.value!["time"] as! Int
let messageModel = MessageModel(name: names, body: bodies, avatar: avatars, date: time)
self.messageModels.append(messageModel)
self.messageModels.sortInPlace{ $0.date > $1.date }
}
self.tableView.reloadData()
})
}
func localChat()
{
self.messageModels.removeAll()
tableView.reloadData()
print("LOCAL")
}
The problem is that each time you call globalChat() you're creating another new observer which results in having multiple observers adding the same items to self.messageModels. Thats why you're seeing the data as many times as you switch to the global state.
Since you want to clear the chat and load the last 100 each time you switch to global, there's no point in keeping the observer active when you switch to "Local".
Just remove the observer when you switch to Local, that should fix your problem.
From firebase docs:
- (void) removeAllObservers
Removes all observers at the current reference, but does not remove any observers at child references.
removeAllObservers must be called again for each child reference where a listener was established to remove the observers.
So, ref.removeAllObservers() will not remove observers at ref.child("messages") level.
Using ref.child("messages").removeAllObservers at the beginning of localChat function to remove the observer you created in globalChat would be ok if you're only dealing with this one observer at this level but if you have more on the same level or you think you might add more in the future the best and safest way would be to remove the specific observer you created. To do that you should use the handle that is returned from starting an observer. Modify your code like this:
var globalChatHandle : FIRDatabaseHandle?
func globalChat()
{
self.messageModels.removeAll()
tableView.reloadData()
ref.child("messages").keepSynced(true)
globalChatHandle = ref.child("messages").queryLimitedToLast(100).observeEventType(.ChildAdded, withBlock: { (snapshot) -> Void in
if snapshot.exists()
{
let names = snapshot.value!["name"] as! String
let bodies = snapshot.value!["body"] as! String
let avatars = snapshot.value!["photo"] as! String
let time = snapshot.value!["time"] as! Int
let messageModel = MessageModel(name: names, body: bodies, avatar: avatars, date: time)
self.messageModels.append(messageModel)
self.messageModels.sortInPlace{ $0.date > $1.date }
}
self.tableView.reloadData()
})
}
func localChat()
{
if globalChatHandle != nil {
ref.child("messages").removeObserverWithHandle(globalChatHandle)
}
self.messageModels.removeAll()
tableView.reloadData()
print("LOCAL")
}
And in viewDidDisappear method replace this
ref.removeAllObservers()
with
ref.child("messages").removeAllObservers()