NSTimer not working while dragging a UITableView

Swift version 4+:

var timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(self.TimerController), userInfo: nil, repeats: true)
RunLoop.main.add(timer, forMode: RunLoopMode.commonModes)

if you want to repeat for example as a counter then set repeat = true else = false

Heres the Swift version:

Swift 2

var timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "removeFromSuperview", userInfo: nil, repeats: false)
NSRunLoop.mainRunLoop().addTimer(timer, forMode: NSRunLoopCommonModes)

Swift 3, 4, 5

var timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(removeFromSuperview), userInfo: nil, repeats: false)
RunLoop.main.add(timer, forMode: RunLoop.Mode.common)

By using scheduledTimerWithTimeInterval:, as j.tom.schroeder says, your timer is automatically schedule on the main run loop for the default modes. This will prevent your timer from firing when your run loop is in a non-default mode, e.g., when tapping or swiping.

The solution, though, is not using a thread, but scheduling your timer for all common modes:

NSTimer *timer = [NSTimer timerWithTimeInterval:1
                                         target:self
                                       selector:@selector(actualizarTiempo:)
                                       userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];

Depending on the kind of events you would like to allow without them stopping your timers, you might also consider UITrackingRunLoopMode. For more info about run loop modes, see Apple Docs.