I am using the starter code Pusher provides, when I put it into a basic swift project and I send it a message nothing happens. I have the cocoa pod package installed as well.
The statement "data received" should print.
There are also no errors.
Are you initialising the Pusher object as a var? You need to maintain a strong reference to the object otherwise it can become deallocated.
As an example it should be something like:
class ViewController: UIViewController {
var pusher: Pusher!
override func viewDidLoad() {
super.viewDidLoad()
let options = PusherClientOptions(
host: .cluster("mycluster")
)
pusher = Pusher(
key: "app_key",
options: options
)
// subscribe to channel and bind to event
let channel = pusher.subscribe("my-channel")
let _ = channel.bind(eventName: "my-event", callback: { (data: Any?) -> Void in
if let data = data as? [String : AnyObject] {
if let message = data["message"] as? String {
print(message)
}
}
})
pusher.connect()
}
}
Related
i have a list of music at my firebase real time database and i am retriving them but i have 1000 musics data and i want to show loader when i reading data and stop loader when if there is a error(internet connection, or something else) or reading completed.
when i turn off the internet i couldn't get the data and can't stop loader to show error alert like there is no internet connection.
please help me how to handle that problem.
here is my code
didload function called from viewdidload()
private var musicArray = [ItemModal]() {
didSet {
view?.updateTableView()
}
}
func didLoad() {
view?.showLoader()
getAllMusics { ItemModal in
self.musicArray = ItemModal
self.view?.hideLoader()
}
}
func getAllMusics(completion: #escaping ([ItemModal]) -> Void) {
var musicArray = [ItemModal]()
ref.child("music").observeSingleEvent(of: .value) { snapshot in
let enumerator = snapshot.children
while let rest = enumerator.nextObject() as? DataSnapshot {
guard let data = try? JSONSerialization.data(withJSONObject: rest.value as Any, options: []) else { return }
if let itemModal = try? JSONDecoder().decode(ItemModal.self, from: data) {
musicArray.append(itemModal)
}
}
completion(musicArray)
}
}
You can use reachability function by using https://github.com/ashleymills/Reachability.swift. To get to notify when the internet is turned off, you can implement reachabilityChanged Notification. In the selector method of reachabilityChanged, you can hide the loader.
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(reachabilityChanged), name: .reachabilityChanged)
}
#objc func changed() {
if reachability?.isReachable {
//Continue success implementation
} else {
view?.hideLoder
//Implement Error handling
}
}
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.
What I am trying to accomplish is posting a notification through NSNotificationCenter's default center. This is being done within a closure block after making a network call using Alamofire. The problem I am having is that a class that should be responding to a posted notification isn't receiving such notification.
My ViewController simply creates a First object that get's things moving:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let first = First()
}
}
My First class creates and instance of a Second class and adds itself as an observer to my NSNotificationCenter. This is the class that can't seem to get the notification when the notification is posted.
class First : NSObject {
let second = Second()
override init(){
super.init()
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(First.gotDownloadNotification(_:)), name: "test", object: nil)
second.sendRequest()
}
// NOT REACHING THIS CODE
func gotDownloadNotification(notification: NSNotification){
print("Successfully received download notification from Second")
}
}
My Second class is what makes the network call through my NetworkService class and posts a notification in a closure once the request is successful and complete.
class Second : NSObject {
func sendRequest(){
let networkService = NetworkService()
networkService.downloadFile() { statusCode in
if let statusCode = statusCode {
print("Successfully got a status code")
// Post notification
NSNotificationCenter.defaultCenter().postNotificationName("test", object: nil)
}
}
}
}
Finally, my NetworkService class is what makes a network call using Alamofire and returns the status code from the response through a closure.
class NetworkService : NSObject {
func downloadFile(completionHandler: (Int?) -> ()){
Alamofire.download(.GET, "https://www.google.com") { temporaryURL, response in
let fileManager = NSFileManager.defaultManager()
let directoryURL = fileManager.URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
let pathComponent = response.suggestedFilename
return directoryURL.URLByAppendingPathComponent(pathComponent!)
}
.response { (request, response, _, error) in
if let error = error {
print("File download failed with error: \(error.localizedDescription)")
completionHandler(nil)
} else if let response = response{
print("File downloaded successfully")
// Pass status code through completionHandler to Second
completionHandler(response.statusCode)
}
}
}
}
The output after execution is:
File downloaded successfully
Successfully got a status code
From this output I know the download was successful and Second got the status code from the closure and posted a notification right after.
I believe that I have tried resolving most other suggestions on Stack Overflow related to not receiving notifications such as objects not being instantiated before notification is posted or syntax of either adding an observer or posting a notification.
Does anyone have any idea why the posted notification is not being received in the First class?
Since there is a direct relationship between First and Second the protocol/delegate pattern is the better way to notify. Even better with this pattern and you don't have to take care of unregistering the observer. NSNotificationCenter is supposed to be used only if there is no relationship between sender and receiver.
And basically the thread doesn't matter either.
protocol SecondDelegate {
func gotDownloadNotification()
}
class Second : NSObject {
var delegate : SecondDelegate?
init(delegate : SecondDelegate?) {
self.delegate = delegate
}
func sendRequest(){
let networkService = NetworkService()
networkService.downloadFile() { statusCode in
if let statusCode = statusCode {
print("Successfully got a status code")
// Post notification
self.delegate?.gotDownloadNotification()
}
}
}
}
class First : NSObject, SecondDelegate {
let second : Second
override init(){
super.init()
second = Second(delegate:self)
second.sendRequest()
}
func gotDownloadNotification(){
print("Successfully received download notification from Second")
}
}
Because I'm sick of misspelling a selector name I figured I'd try to do some notification stuff with blocks instead of selectors.
I've put together some sample code that doesn't seem to work because I'm unable to access self
var currentString : String?
// Type alias the notificaitonBlock
typealias notificationBlock = (NSNotification?) -> ()
// in this case note is an NSNotification?
let strNotification : notificationBlock = { notification in
if let msg = notification?.object as? String {
self.currentString = msg
}
}
Assuming this code worked I would register it with:
nc.addObserverForName(UIDeviceOrientationDidChangeNotification,
object: self,
queue: NSOperationQueue.currentQueue(),
usingBlock: strNotification)
Xcode is giving me the following error:
NotificationTests.swift:49:4: 'NotificationTests -> () -> NotificationTests' does not have a member named 'currentString'
which implies self isn't pointing to the class but the block or something?
You could either use this when using an instance variable for the block:
lazy var block: (NSNotification?) -> () = { notification in
if let msg = notification?.object as? String {
self.currentString = msg
}
}
or inside a method call:
func registerObeserver() {
NSNotificationCenter.defaultCenter().addObserverForName(UIDeviceOrientationDidChangeNotification, object: self, queue: NSOperationQueue.currentQueue(), { notification in
if let msg = notification?.object as? String {
self.currentString = msg
}
})
}
As Martin R mentioned in the comments this probably has to do with one property of a class depending on another during initialization
Unlike this in javascript, self is not changing inside a closure