I have a project in which I need to update the user's current location coordinates on the API server. How can I achieve this? Is continuously calling the API a good idea (I think no)?
I need to update coordinates continuously so other users can see me like in the Uber app the very first time we can see drivers near me.
Maybe you can implement a timer, and make a POST request by sending your lat long periodically.
class ViewController: UIViewController {
var timer: Timer!
override func viewDidLoad() {
timer = Timer.scheduledTimer(timeInterval: 10.0, target: self, selector: #selector(makeRequest), userInfo: nil, repeats: true)
}
#objc func makeRequest() {
// make your post request here.
}
}
For example the timer given above will call makeRequest method every 10 seconds.
If you don't know much about networking, make a research on the following topics:
Swift Networking Layer, Alamofire, URLSession
**Step 1 :- Get latitude and long. of the user first.**
Reference URL:- https://stackoverflow.com/questions/12736086/how-to-get-location-latitude-longitude-value-in-variable-on-ios
**Step 2:- Define following variables globally.**
var timer:Timer?
var sourceLatitude = CLLocationDegrees()
var sourceLongitude = CLLocationDegrees()
**Step 3:- Setup timer for continuous update as below.**
override func viewDidLoad()
{
super.viewDidLoad()
timer = Timer.scheduledTimer(timeInterval: 15, target: self, selector: #selector(self.updateDriverLoction), userInfo: nil, repeats: true)
}
**Step 4:- call appropriate method for sending and updating lat. long. to the server using any of networking API.(In my case I have used Alamofire)**
// must be internal or public.
#objc func updateDriverLoction() {
if Reachability.isConnectedToNetwork() {
let param1:[String:String] = [
"latitude" : "\(sourceLatitude)",
"longitude" : "\(sourceLongitude)"
]
ServerClass.sharedInstance.putRequestWithUrlParameters(param1, path: BASE_CAB_URL + PROJECT_URL.UPDATE_DRIVER_LOCATION_API, successBlock: { (json) in
print(json)
let success = json["success"].stringValue
if success == "true" {
}
else {
}
}, errorBlock: { (NSError) in
// UIAlertController.showInfoAlertWithTitle("Alert", message: kUnexpectedErrorAlertString, buttonTitle: "Okay")
})
}
}
else{
UIAlertController.showInfoAlertWithTitle("Alert", message: "Please Check internet connection", buttonTitle: "Okay")
}
}
Related
I'm using CallKit to connect Twilio RTC and I'd like to know more about CallKit.
There is a timer in the lock screen of the CallKit and I am trying to start the timer after I receive response from the server. Right now the timer would just start counting right after the "connecting" phase, in which my response haven't even started yet.
It seems like starting after calling [action fulfill], but how should I implement with the http call? or Twilio function?
If I'm calling from the call history of the native call app made by Apple, where should I store the mapping information for UUID to the user-id I'd like to call?
I know that the callee can save these information in CXUpdate and show without problem, but how about the caller? I can't tell from the examples of saving call information in CXHandle.
Thanks ahead for reading through :)
Intiate call timer after call connecting state to connected
var callTimer: Timer?
var timeDuration: TimeInterval = 0.0
//MARK:- CallTimer
func initiateCallTimer() {
if callTimer == nil {
self.callTimer = Timer.scheduledTimer(timeInterval: kRefreshTimeInterval, target: self, selector: #selector(CallViewController.refreshCallTimer(_:)), userInfo: nil, repeats: true)
}
}
func callTimerInvalidate() {
if callTimer != nil {
callTimer?.invalidate()
callTimer = nil
}
}
#objc func refreshCallTimer(_ sender: Timer) {
timeDuration += kRefreshTimeInterval
print(timeDuration)
self.lblConnectiong.text = string(withTimeDuration: timeDuration)
}
func string(withTimeDuration timeDuration: TimeInterval) -> String? {
let minutes = Int(timeDuration / 60)
let seconds = Int(timeDuration) % 60
let timeStr = String(format: "%ld:%02ld", minutes, seconds)
return timeStr
}
and invalidate after rejected or end
self.callTimerInvalidate()
for this call from recent call list
In your app's Info.plist, you must have INStartAudioCallIntent and/or INStartVideoCallIntent in the NSUserActivityTypes key, and your app delegate must implement the -application:continueUserActivity:restorationHandler: method to handle the start call intent.
How can I run a function every minute?
In JavaScript I can do something like setInterval, does something similar exist in Swift?
Wanted output:
Hello World once a minute...
var helloWorldTimer = NSTimer.scheduledTimerWithTimeInterval(60.0, target: self, selector: Selector("sayHello"), userInfo: nil, repeats: true)
func sayHello()
{
NSLog("hello World")
}
Remember to import Foundation.
Swift 4:
var helloWorldTimer = Timer.scheduledTimer(timeInterval: 60.0, target: self, selector: #selector(ViewController.sayHello), userInfo: nil, repeats: true)
#objc func sayHello()
{
NSLog("hello World")
}
If targeting iOS version 10 and greater, you can use the block-based rendition of Timer, which simplifies the potential strong reference cycles, e.g.:
weak var timer: Timer?
func startTimer() {
timer?.invalidate() // just in case you had existing `Timer`, `invalidate` it before we lose our reference to it
timer = Timer.scheduledTimer(withTimeInterval: 60.0, repeats: true) { [weak self] _ in
// do something here
}
}
func stopTimer() {
timer?.invalidate()
}
// if appropriate, make sure to stop your timer in `deinit`
deinit {
stopTimer()
}
While Timer is generally best, for the sake of completeness, I should note that you can also use dispatch timer, which is useful for scheduling timers on background threads. With dispatch timers, since they're block-based, it avoids some of the strong reference cycle challenges with the old target/selector pattern of Timer, as long as you use weak references.
So:
var timer: DispatchSourceTimer?
func startTimer() {
let queue = DispatchQueue(label: "com.domain.app.timer") // you can also use `DispatchQueue.main`, if you want
timer = DispatchSource.makeTimerSource(queue: queue)
timer!.schedule(deadline: .now(), repeating: .seconds(60))
timer!.setEventHandler { [weak self] in
// do whatever you want here
}
timer!.resume()
}
func stopTimer() {
timer = nil
}
For more information, see the the Creating a Timer section of Dispatch Source Examples in the Dispatch Sources section of the Concurrency Programming Guide.
For Swift 2, see previous revision of this answer.
If you can allow for some time drift here's a simple solution executing some code every minute:
private func executeRepeatedly() {
// put your code here
DispatchQueue.main.asyncAfter(deadline: .now() + 60.0) { [weak self] in
self?.executeRepeatedly()
}
}
Just run executeRepeatedly() once and it'll be executed every minute. The execution stops when the owning object (self) is released. You also can use a flag to indicate that the execution must stop.
Here's an update to the NSTimer answer, for Swift 3 (in which NSTimer was renamed to Timer) using a closure rather than a named function:
var timer = Timer.scheduledTimer(withTimeInterval: 60, repeats: true) {
(_) in
print("Hello world")
}
You can use Timer (swift 3)
var timer = Timer.scheduledTimerWithTimeInterval(60, target: self, selector: Selector("function"), userInfo: nil, repeats: true)
In selector() you put in your function name
In swift 3.0 the GCD got refactored:
let timer : DispatchSourceTimer = DispatchSource.makeTimerSource(flags: [], queue: DispatchQueue.main)
timer.scheduleRepeating(deadline: .now(), interval: .seconds(60))
timer.setEventHandler
{
NSLog("Hello World")
}
timer.resume()
This is specially useful for when you need to dispatch on a particular Queue. Also, if you're planning on using this for user interface updating, I suggest looking into CADisplayLink as it's synchronized with the GPU refresh rate.
Here is another version algrid's answer with an easy way to stop it
#objc func executeRepeatedly() {
print("--Do something on repeat--")
perform(#selector(executeRepeatedly), with: nil, afterDelay: 60.0)
}
Here's an example of how to start it and stop it:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
executeRepeatedly() // start it
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NSObject.cancelPreviousPerformRequests(withTarget: self) // stop it
}
timer = Timer.scheduledTimer(withTimeInterval: 60, repeats: true, block: myMethod)
func myMethod(_:Timer) {
...
}
or
timer = Timer.scheduledTimer(withTimeInterval: 60, repeats: true) { _ in
...
}
make sure to invalid the timer at some point like your time is no longer visible, or you object is deist
As a swift beginner, I'm building a simple app which will get data from a website to update the label text.
In the ViewController.swift I begin with a function called requestCycle():
override func viewDidLoad() {
super.viewDidLoad()
requestCycle()
}
In this requestCycle() function I create a timer to call the http request function basicAuthHttpRequest():
func requestCycle(){
self.timer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(ViewController.basicAuthHttpRequest), userInfo: nil, repeats: true);
RunLoop.current.add(self.timer, forMode: RunLoopMode.commonModes);
}
In the basicAuthHttpRequest() function, I set up an http request to get data from a url, and use the data to update the label text:
...
//http request, parse json, store the data in TempIn
let TempInString = String(describing: TempIn!)
self.TempInLabel.text = TempInString
print(TempInString)
print(self.TempInLabel.text!)
...
When I run the app, the data will be printed("33" and Optional("33")) and NO ERRORs occur. However, the text of the label shown is not changed at all.
If I use a button to trigger the function basicAuthHttpRequest(), after clicking the button, the label text will be changed in a few seconds.
What's wrong with my poor timer? =.=
You have to update text on the main thread.
DispatchQueue.main.async {
let TempInString:String = String(describing: TempIn!)
self.TempInLabel.text = TempInString as String
}
Try below code :-
DispatchQueue.main.async(execute: { self.TempInLabel.text = TempInString as String })
The timer is running on background thread. so you have to update label value with main thread. You have to use below code for the same.
self.performSelector(onMainThread: #selector(updateUI), with: nil, waitUntilDone: true)
func updateUI() {
print("here update your UI")
}
Also you can do with OperationQueue.
OperationQueue.main.addOperation({
print("here update your UI")
})
I have two views in my swift app. I am performing a segue as below.
ViewController.swift -----------------> GameViewController.swift
When loading the GameViewController an value array also passed to GameViewController.swift from ViewController.swift
A timer should be initialized in GameViewController.swift
I tried to initialize a timer and call a method through it, but it doesn't work.
Followings are my code snippets.
ViewController.swift
func signIn(difficultyLvl:String){
let username = usernameTxt.text
let password = passwordTxt.text
let url = URL(string: "http://192.168.1.106/speed/scoreBoardController.php?username="+username!+"&password="+password!+"&action=SIGNIN")
let task = URLSession.shared.dataTask(with: url!) {(data, response, error) in
let isPassed = String(data: data!, encoding:.utf8)?.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
var gameViewControllerParams = [Int: [String: String]]()
gameViewControllerParams[0] = ["userId" : isPassed!]
gameViewControllerParams[1] = ["difficultyLvl" : difficultyLvl]
if(isPassed != "null"){
self.performSegue(withIdentifier: "gotoGame", sender: gameViewControllerParams)
}
}
task.resume()
}
GameViewController.swift
class GameViewController: UIViewController {
var gameViewControllerParams = [Int: [String: String]]()
override func viewDidLoad() {
super.viewDidLoad()
let _ = Timer.scheduledTimer(timeInterval: 1.0, target:self, selector: #selector(self.setCalculationLs), userInfo:nil,repeats: true)
}
func setCalculationLs(){
print("Timing")
}
}
Timers don't work on background queues (without some sleight of hand involving creating run loops or manually scheduling it on an existing run loop). But you should never initiate any UI update from anything other than the main queue, anyway.
So, since you're calling performSegue from a URLSession completion closure (which runs on a background queue), it's actually running viewDidLoad from the background queue, too. Thus the attempt to schedule the timer is failing. To get around this, you have to manually dispatch the performSegue code to the main queue:
let task = URLSession.shared.dataTask(with: url!) { data, response, error in
...
if isPassed != "null" {
DispatchQueue.main.async {
self.performSegue(withIdentifier: "gotoGame", sender: ...)
}
}
}
If you're ever unsure whether some code is running on the main queue or not, refer to the documentation. Or you can use a dispatch precondition:
dispatchPrecondition(condition: .onQueue(.main))
That way it will (in debug builds) stop the app if you've accidentally invoked the code from a background queue.
Unrelated to your current problem, but as an aside, to avoid a strong reference cycle between the timer and the view controller, you generally want to keep a reference to the timer so that you can invalidate it when the view disappears (e.g. create timer in viewDidAppear and remove it in viewDidDisappear). Otherwise you can end up retaining the GameViewController after it was dismissed, e.g.:
class GameViewController: UIViewController {
weak var timer: Timer?
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
timer = Timer.scheduledTimer(timeInterval: 1.0, target:self, selector: #selector(setCalculationLs(_:)), userInfo: nil, repeats: true)
}
override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
timer?.invalidate()
}
#objc func setCalculationLs(_ timer: Timer) {
print("Tick")
}
}
Or in iOS 10 or later, you can use the block-based variant with weak reference to self, and invalidate in deinit:
class GameViewController: UIViewController {
weak var timer: Timer?
override func viewDidLoad() {
super.viewDidLoad()
timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] timer in
self?.setCalculationLs()
}
}
deinit {
timer?.invalidate()
}
func setCalculationLs() {
print("Tick")
}
}
Swift 5.5
I was having this issue as well while working in a segued view controller. Since segues are executed as a background thread to the main thread (main view controller), running timer within the segued view controller won't work. So, that being known and also knowing timers don't work in background threads, I did some digging and found this Apple Documentation gem.
I added the following line right after my scheduled timer. The timer now works beautifully. It is just sending the timer to the main thread for execution.
myTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.updateWithTimer), userInfo: nil, repeats: true)
RunLoop.main.add(myTimer, forMode: .common)
I want to call the method func adjustmentBestSongBpmHeartRate() every 1.1 second. I used Timer, but it doesn't work. I have read the document and found a lot of sample code, it still does work! Is there anything I missed?
timer = Timer.scheduledTimer(timeInterval: 1.1, target: self, selector: #selector(self.adjustmentBestSongBpmHeartRate), userInfo: nil, repeats: false)
timer.fire()
func adjustmentBestSongBpmHeartRate() {
print("frr")
}
I found that creating the timer in an OperationQueue Operation did not work. I assume this is because there is no runloop.
Therefore, the following code fixed my problem:
DispatchQueue.main.async {
// timer needs a runloop?
self.timeoutTimer = Timer.scheduledTimer(timeInterval: self.timeout, target: self, selector: #selector(self.onTimeout(_:)), userInfo: nil, repeats: false)
}
Timer methods with a selector are supposed to have one parameter: The timer itself. Thus your code should really look like this: 1
Timer.scheduledTimer(timeInterval: 1.1,
target: self,
selector: #selector(self.adjustmentBestSongBpmHeartRate(_:),
userInfo: nil,
repeats: false)
#objc func adjustmentBestSongBpmHeartRate(_ timer: Timer) {
print("frr")
}
Note that if your app only runs on iOS >= 10, you can use the new method that takes a block to invoke rather than a target/selector. Much cleaner and more type-safe:
class func scheduledTimer(withTimeInterval interval: TimeInterval,
repeats: Bool,
block: #escaping (Timer) -> Void) -> Timer
That code would look like this:
timer = Timer.scheduledTimer(withTimeInterval: 1.1,
repeats: false) {
timer in
//Put the code that be called by the timer here.
print("frr")
}
Note that if your timer block/closure needs access to instance variables from your class you have to take special care with self. Here's a good pattern for that sort of code:
timer = Timer.scheduledTimer(withTimeInterval: 1.1,
repeats: false) {
//"[weak self]" creates a "capture group" for timer
[weak self] timer in
//Add a guard statement to bail out of the timer code
//if the object has been freed.
guard let strongSelf = self else {
return
}
//Put the code that be called by the timer here.
print(strongSelf.someProperty)
strongSelf.someOtherProperty = someValue
}
Edit (updated 15 December)
1: I should add that the method you use in the selector has to use Objective-C dynamic dispatch. In Swift 4 and later, the individual methods you reference must be tagged with the #objc tag. In previous versions of Swift you could also declare the entire class that defines the selector with the #objc qualifier, or you could make the class that defined the selector a subclass of NSObject or any class that inherits from NSOBject. (It's quite common to define the method the timer calls inside a UIViewController, which is a subclass of NSObject, so it used to "just work".
Swift 3
In my case it worked after I added to my method the #obj prefix
Class TestClass {
private var timer: Timer?
func start() {
guard timer == nil else { return }
timer = Timer.scheduledTimer(timeInterval: 60, target: self, selector: #selector(handleMyFunction), userInfo: nil, repeats: false)
}
func stop() {
guard timer != nil else { return }
timer?.invalidate()
timer = nil
}
#objc func handleMyFunction() {
// Code here
}
}
Try this -
if #available(iOS 10.0, *) {
self.timer = Timer.scheduledTimer(withTimeInterval: 0.2, repeats: false, block: { _ in
self.update()
})
} else {
self.timer = Timer.scheduledTimer(timeInterval: 0.2, target: self, selector: #selector(self.update), userInfo: nil, repeats: false)
}
Mostly the problem must have been because of iOS version of mobile.
Swift 5, Swift 4 Simple way only call with Dispatch Queue Async
DispatchQueue.main.async
{
self.andicator.stopAnimating()
self.bgv.isHidden = true
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: false, block: { _ in
obj.showAlert(title: "Successfully!", message: "Video save successfully to Library directory.", viewController: self)
})
}
I have solved the question asked by myself.
I'm using apple watch to control my iphone app.
I try to press a button on apple watch to present a new viewcontroller on iphone.
When I write Timer in override func viewDidLoad(), Timer doesn't work. I move Timer to override func viewWillAppear() it works.
I think maybe there's something wrong with controlling by apple watch
I found that if you try to initialize the timer directly at the class-level, it won't work if you're targeting a selector in that same class. When it fires, it can't find the selector.
To get around this, I only initialize the timer after the object containing the selector has been initialized. If it's in the same class, put the initialization code in the ViewDidLoad or similar. Just not in the initializer. Then it will work. No dispatch queue needed.
Also, you do not need to use a selector that accepts the timer as a parameter. You can, but contrary to the answer with a ton of votes, that's not actually true, or more specifically, it works fine for me without it, just as you have it without it.
By the way, I think the reason the dispatch queue worked is because you're forcing the timer to be created after the object was initializing, confirming my above statement.
let timer:Timer?
override func viewDidLoad(){
super.viewDidLoad()
timer = Timer.scheduledTimer(timeInterval: 1.1, target: self, selector: #selector(adjustmentBestSongBpmHeartRate), userInfo: nil, repeats: false)
timer.fire()
}
func adjustmentBestSongBpmHeartRate() {
print("frr")
}
Note: This is code typed from memory, not copied from Xcode so it may not compile, but hopefully you get the idea.
Swift3
var timer = Timer()
timer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.compruebaConexion), userInfo: nil, repeats: true)
my two cents.
I read about "didLoad" and when invoking it.
so we can use a delay:
class ViewController: UIViewController {
var timer: Timer?
override func viewDidLoad() {
super.viewDidLoad()
startTimer()
}
final func killTimer(){
self.timer?.invalidate()
self.timer = nil
}
final private func startTimer() {
// make it re-entrant:
// if timer is running, kill it and start from scratch
self.killTimer()
let fire = Date().addingTimeInterval(1)
let deltaT : TimeInterval = 1.0
self.timer = Timer(fire: fire, interval: deltaT, repeats: true, block: { (t: Timer) in
print("hello")
})
RunLoop.main.add(self.timer!, forMode: RunLoopMode.commonModes)
}