NSTimer never call the selector function (Swift) - ios

Question

keep calm, most probably this question is not a duplicate.
I have already tried all solutions in stack overflow, but nothing worked for me.
I have a client thread that send and receive a "keepalive" string (a ping) continually from another host. If it doesn't receive the "keepalive" within the KeepAliveMax, it closes the streams and say good bye (in theory, but this yet work in progress).
Now my problem is that I used a NSTimer to call the updateKeepAlive function, but it is never invoked..I don't understand why :(
I have tried also to set the NSTimer RunLoop manually, but it not works
The follow is the part of code where the selector function should be initialized and called every second:
public class Client: NSObject, NSStreamDelegate {
var serverAddress: CFString
let serverPort: UInt32 = 50000
private var inputStream: NSInputStream!
private var outputStream: NSOutputStream!
private var connecting:Bool
private var byteRead:Int
private var byteWrite:Int
private let keepAliveMax:Double = 5000
private var keepAliveTime:Double
private var connected:Bool
var timer: NSTimer?
init(ip:String) {
serverAddress = ip
connecting = false
connected = false
byteRead = 0
byteWrite = 0
keepAliveTime = 0
super.init()
let thread = NSThread(target:self, selector:#selector(connect), object:nil)
thread.start()
print("thread is started and now I can continue with other tasks..")
}
func connect() {
connecting = true
while connecting {
print("connecting...")
var readStream: Unmanaged<CFReadStream>?
var writeStream: Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(nil, self.serverAddress, self.serverPort, &readStream, &writeStream)
// Documentation suggests readStream and writeStream can be assumed to
// be non-nil. If you believe otherwise, you can test if either is nil
// and implement whatever error-handling you wish.
self.inputStream = readStream!.takeRetainedValue()
self.outputStream = writeStream!.takeRetainedValue()
self.inputStream.delegate = self
self.outputStream.delegate = self
self.inputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.outputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.inputStream.open()
self.outputStream.open()
// send handshake
byteWrite = writeLine("handshake")
print("written: \(byteWrite) for handshake")
// wait to receive handshake
print("waintig for handshake...")
if readLine() == "handshake" {
connected = true
print("Client: connection estabilished correctly")
// close the waiting popup and start with SendBox...
// in progress...
// send keepAlive
byteWrite = writeLine("keepalive")
print("written: \(byteWrite) for keepalive")
//======================== THIS NOT WORK PROPERLY ============================================================
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: #selector(Client.updateKeepAlive), userInfo: nil, repeats: true)
/*
timer = NSTimer(timeInterval: 1, target: self, selector: #selector(Client.updateKeepAlive), userInfo: nil, repeats: true)
NSRunLoop.currentRunLoop().addTimer(timer!, forMode: NSRunLoopCommonModes)
*/
//============================================================================================================
keepAliveTime = NSDate().timeIntervalSince1970 * 1000
print("Client: Timer started")
while self.inputStream.streamStatus != NSStreamStatus.Closed ||
self.outputStream.streamStatus != NSStreamStatus.Closed
{
print("Client: under the while of keepAlive");
if readLine() == "keepalive"
{
keepAliveTime = NSDate().timeIntervalSince1970 * 1000
writeLine("keepalive")
print("Client: keepalive received");
}
else
{
print("Client: not keepalive: ");
// close streams...... work in progress
break
}
sleep(1)
}
}
else{
print("wrong handshake")
}
print("closing streams..")
connecting = false
self.inputStream.close()
self.outputStream.close()
self.timer?.invalidate()
}
}
And the follow is the updateKeepAlive function:
func updateKeepAlive(){
print("in updateKeepalive function") // <---- NEVER PRINTED
/* in progress .....
........./*
}

Answer 1

In a new thread begining, there is no input sources or timers are attached to the run loop. So the run loop while not be active. You can call run function after call scheduledTimerWithTimeInterval.
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: #selector(TimerTest.updateKeepAlive), userInfo: nil, repeats: true)
NSRunLoop.currentRunLoop().run()