Question

Here is my code. I expected the timer to stop in 5 second after it starts but it doesn’t. What is wrong here ?

-(void)loadView
{
NSTimeInterval startTime = [NSDate timeIntervalSinceReferenceDate];



NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.0
                                 target:self
                               selector:@selector(targetMethod:)
                               userInfo:nil
                                repeats:YES];
if([NSDate timeIntervalSinceReferenceDate] - startTime >= 5) {
    [timer invalidate];
}

}

-(void)targetMethod:(NSTimer *)timer {


    NSLog(@"bla");
}

Answer 1

NSDate’s timeIntervalSinceReferenceDate is, by default, returning January 1st, 2001. Subtracting the same values will always be 0.

Apple’s documentation:
https://developer.apple.com/library/mac/ipad/#documentation/Cocoa/Reference/Foundation/Classes/NSDate_Class/Reference/Reference.html

Here’s an idea:
In your .h

@interface MyClass : NSObject

@property (nonatomic, retain) NSTimer *timer;

- (void)targetMethod:(NSTimer *)timer;
- (void)cancelTimer;

@end

In your .m

@implementation MyClass

@synthesize timer;

-(void)loadView
{
    self.timer = [NSTimer scheduledTimerWithTimeInterval:0.0
                                             target:self
                                           selector:@selector(targetMethod:)
                                           userInfo:nil
                                            repeats:YES];
    [self performSelector:@selector(cancelTimer) withObject:nil afterDelay:5.0];
}

-(void)cancelTimer {
    [self.timer invalidate];
}

-(void)targetMethod:(NSTimer *)timer {
    NSLog(@"bla");
}