Selector is not fired from scheduledTimerWithTimeInterval - ios

Question

I checked the existing posts on this topic and also googled it, but I am not able to identify my mistake or make this work for me. I have a function iterativeDeepening() inside the class ChessPlayer. After say 15 seconds I want to stop further iterations within the function. In the code below, the function "flagSetter" is never invoked. If I use NSTimer.fire() the function is invoked immediately and not after 15 seconds. I tried placing the flagSetter function before or after iterativeDeepening(). Either case does not work. What have I done incorrectly?
class ChessPlayer {
var timeoutFlag = false
//Code
func iterativeDeepening() {
***//variables and constants***
let timer = NSTimer.scheduledTimerWithTimeInterval(15.0, target: self, selector: #selector(self.flagSetter), userInfo: nil, repeats: false)
***while minDepth <= maxDepth
{
// Loop iteration code
if timeoutFlag { break out of loop }
}***
}
#objc func flagSetter(timer: NSTimer) {
print("flag changed to true")
self.timeoutFlag = true
timer.invalidate()
}
}
The requirement:
computerThinking() is fired from GameScene from human move's action completion handler.
GameScene.computerThinking() invokes ChessPlayer.iterativeDeepening()
iterativeDeepening runs a while loop incrementing "depth". For each "depth" an optimal move at that depth is evaluated. Higher the depth, more detailed the evaluation.
after 15.0 seconds i want to break out of the while loop with the depth and optimal move available at that point of time.

Answer 1

I am a lover of Objective-c and never used Swift yet in my projects. Googling NSTimer Swift, I found out the following steps to implement NSTimer correctly.
we need to define our NSTimer. The first variable that we are going to need is a variable called timer of type NSTimer. We do this like:
var timer = NSTimer()
Start NSTimer timer:
timer = NSTimer.scheduledTimerWithTimeInterval(15.0, target:self, selector:#selector(ChessPlayer.flagSetter(_:)), userInfo: nil, repeats: false)
And your method flagSetter should be defined as this:
func flagSetter(timer: NSTimer) {
print("flag changed to true")
self.timeoutFlag = true
timer.invalidate()
}
This will now surely work as I've made my very first app, just for this question, made in Swift. Check how I put my selector. You're right with the warnings by the way.
If you need more information about Selectors, check this thread: #selector() in Swift?

Answer 2

Here is your solution: define timer outside of the function so you can invalidate it from another function. Right now, your timer is defined inside a function so it can only be altered inside that function, but that is not what you want. Fix it by doing the following: right below var timeoutFlag = false put var timer = NSTimer(). Then inside your function iterativeDeepening() get rid of the let. Then it will all work!!
Here's what your code should be, adapted from Hasya's answer and your provided code.
class ChessPlayer {
// Declare timer and timeoutFlag
var timer = NSTimer()
var timeoutFlag = false
func iterativeDeepening() {
self.timer = NSTimer.scheduledTimerWithTimeInterval(15.0, target: self, selector: “timerEventOccured”, userInfo: nil, repeats: true)
}
func timerEventOccured() {
print("timerEventOccured was called.")
timeoutFlag = true
self.timer.invalidate()
}
}
override func viewDidUnload() {
super.viewDidUnload()
self.timer.invalidate()
}
}