Swift 3 - How to make timer work in background
Solution 1
you can go to Capabilities and turn on background mode and active Audio. AirPlay, and picture and picture.
It really works . you don't need to set DispatchQueue . you can use of Timer.
Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { (t) in
print("time")
}
Solution 2
A timer can run in the background only if both the following are true:
Your app for some other reason runs in the background. (Most apps don't; most apps are suspended when they go into the background.) And:
The timer was running already when the app went into the background.
Solution 3
This works. It uses while loop inside async task, as suggested in another answer, but it is also enclosed within a background task
func executeAfterDelay(delay: TimeInterval, completion: @escaping(()->Void)){
backgroundTaskId = UIApplication.shared.beginBackgroundTask(
withName: "BackgroundSound",
expirationHandler: {[weak self] in
if let taskId = self?.backgroundTaskId{
UIApplication.shared.endBackgroundTask(taskId)
}
})
let startTime = Date()
DispatchQueue.global(qos: .background).async {
while Date().timeIntervalSince(startTime) < delay{
Thread.sleep(forTimeInterval: 0.01)
}
DispatchQueue.main.async {[weak self] in
completion()
if let taskId = self?.backgroundTaskId{
UIApplication.shared.endBackgroundTask(taskId)
}
}
}
}
Solution 4
Timer won't work in background. For background task you can check this link below...
https://www.raywenderlich.com/143128/background-modes-tutorial-getting-started
Solution 5
============== For Objective c ================
create Global uibackground task identifier.
UIBackgroundTaskIdentifier bgRideTimerTask;
now create your timer and add BGTaskIdentifier With it, Dont forget to remove old BGTaskIdentifier while creating new Timer Object.
[timerForRideTime invalidate];
timerForRideTime = nil;
bgRideTimerTask = UIBackgroundTaskInvalid;
UIApplication *sharedApp = [UIApplication sharedApplication];
bgRideTimerTask = [sharedApp beginBackgroundTaskWithExpirationHandler:^{
}];
timerForRideTime = [NSTimer scheduledTimerWithTimeInterval:1.0
target:self
selector:@selector(timerTicked:)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop]addTimer:timerForRideTime forMode: UITrackingRunLoopMode];
Here this will work for me even when app goes in background.ask me if you found new problems.
Admin
Updated on September 17, 2020Comments
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Admin over 3 years
i am trying to do an application which can make a timer run in background.
here's my code:
let taskManager = Timer.scheduledTimer(timeInterval: 10, target: self, selector: #selector(self.scheduleNotification), userInfo: nil, repeats: true) RunLoop.main.add(taskManager, forMode: RunLoopMode.commonModes)
above code will perform a function that will invoke a local notification. this works when the app is in foreground, how can i make it work in the background?
i tried to put several print lines and i saw that when i minimize (pressed the home button) the app, the timer stops, when i go back to the app, it resumes.
i wanted the timer to still run in the background. is there a way to do it?
here's what i want to happen:
run app -> wait 10 secs -> notification received -> wait 10 secs -> notification received -> and back to wait and received again
that happens when in foreground. but not in background. pls help.