How to update a textfield periodically? - ios

Question

I'm building an app which it communicates with socket periodically.
As long as the socket is open, then data will be transmitting from time to time.
However, my textFields(representing the data) do not update itself unless another view is introduces.
From the image above, initially my app will scans for the QR code as authentication method. Assuming authentication succeeded and the First view is loaded(the view after navigation controller).
The problem is it took quite some time to get the data.
Code that describe how I maneuver the connection.
override func viewDidLoad() {
super.viewDidLoad()
print("First view loaded")
//add observer
NSNotificationCenter.defaultCenter().addObserver(self, selector: "reachabilityStatusChanged", name: "ReachStatusChanged", object: nil)
reachabilityStatusChanged()
}
func reachabilityStatusChanged(){
switch reachabilityStatus{
case NOACCESS:
print("No access")
dispatch_async(dispatch_get_main_queue()){
print("No-access")
self.displayAlertMessage("No internet access, please try again later")
}
default:
dispatch_async(dispatch_get_main_queue()){
self.api.reportStatus()
self.api.importData()
socket.connect()
//data will be sent to text field at this point
}
}
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
print("First view appeared")
self.circleProgressView.progress = progressSliderValue
dispatch_async(dispatch_get_main_queue()){
self.distanceLabel.text = "\(appUserMileage)"
self.mileageLabel.text = "Target: \(appUserTarget) km"
}
}
From the code above as you can tell as the view is loaded(the view after navigation controller), it checks for network access. If network available then it will communicate with socket but by the time data gets in, the view is already loaded and appeared which means no data will be displayed at that time.
Is there a way to update the views periodically? I've done some research but all of them is about background fetching data which isn't suitable for my case.

Answer 1

I don't know where your appUserMileage and appUserTarget variables live, but how about something like this?
var appUserMileage: Int? {
didSet {
self.distanceLabel?.text = "\(appUserMileage ?? 0)" //? in case model calls this before outlets are loaded
}
}
var appUserTarget: Int? {
didSet {
self.mileageLabel?.text = "Target: \(appUserTarget ?? 0) km"
}
}