问题:

I am creating and firing a NSTimer with:

ncTimer = [NSTimer scheduledTimerWithTimeInterval:1.0
                                           target:self
                                         selector:@selector(handleTimer:)
                                         userInfo:nil
                                          repeats:YES];
[ncTimer fire];

AND

- (void)handleTimer:(NSTimer *)chkTimer {
    // do stuff
}

I am retaining my timer with:

@property (nonatomic, retain) NSTimer *ncTimer;

For some reason the timer is not repeating. It is firing once only and than never again.

回答1:

You can't just assign to the timer that you have put as a property in your header. This should work:

self.ncTimer = [NSTimer scheduledTimerWithTimeInterval:1.0
 target:self selector:@selector(handleTimer:) userInfo:nil repeats: YES];

Also: The fire method fires the timer, out of cycle. If the timer is non repeating it is invalidated. After the line that says fire, add this:


BOOL timerState = [ncTimer isValid];
NSLog(@"Timer Validity is: %@", timerState?@"YES":@"NO");

回答2:

The -fire: method manually fires it once. For a timer to be started and repeat, you have to add it to a runloop using [[NSRunLoop currentRunLoop] addTimer: forMode:]