How to run an action for a set period time?

Question

I am trying to scan for bluetooth devices for 5s. However I am unable to implement the time phase. My code currently looks like this:

@IBAction func scanButton(_ sender: Any)
{
    startScanning()
    let disableScanButton = sender as? UIButton
    disableScanButton?.isEnabled = true
}

func startScanning()
{
    timer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(ViewController.stopScanning), userInfo: nil, repeats: true)
    print("Start Scan")
    manager?.scanForPeripherals(withServices: nil, options: nil)
    print("There are \(peripheralArray.count) no. of peripherals counted for")
    stopScanning()
}

func stopScanning()
{
    timer?.invalidate()
    print("timer stopped")
    manager?.stopScan()
    print("Scan Stopped")
}

So I press the button and then it scans. However, it just seems to jump through all the actions really quickly. I thought the timer would hold it, but it does not. Is there someway to loop it for the startScanning function?

I have looked at other people, but I can't seem to find anything. And those that do seem very complex.

I am looking for a solution, simpler the better. However, if simple is not possible then I am open to whatever options people have.

Answer 1

You could achieve this delay as suggested by @Larme Here I am rewriting your code with @larme's approach

@IBAction func scanButton(_ sender: Any)
{
    startScanning()
    let disableScanButton = sender as? UIButton
    disableScanButton?.isEnabled = true
}

func startScanning()
{
    manager?.scanForPeripherals(withServices: nil, options: nil)
    self.performSelector(#selector(stopScanning), withObject: self, afterDelay: 5)//here 5 is number of seconds after you want to execute stopScanning function, Increase the time interval or decrease it as your conviniebce


}

func stopScanning()
{
    manager?.stopScan()
    print("Scan Stopped")
    print("There are \(peripheralArray.count) no. of peripherals counted for")
}

Now NSTimer is not required anymore with your code.and you may increase or decrease the time interval to stop your scanning