Question

I have a timer which will be initialized on viewDidLoad, and be released on viewDidUnload, but I found the viewDidUnload nerver be called and each time the view is presented to user the viewDidLoad is called, so I have many timers running simultaneously… which is not what I want.

I just want to stop&release the timer when user navigate away from this view, how can I do that?

Answer 1

Don’t initialize it on view did load, instead initialize it in view will apper and stop it in view will dissapear, that way it will stop when you navigate away and restart once you come back to that view.

I had the exact same problem you are having. This is the code just in case you need it:

- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
NSLog(@"View will appear");
myTimer = [NSTimer timerWithTimeInterval:5.0 target:self selector:@selector(pageCycler) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer: myTimer forMode: NSDefaultRunLoopMode];
}

- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
NSLog(@"View will dissapear");
[myTimer invalidate];
myTimer=nil;
}