Question about NSTimer and retain

Question

This code works well

@property (nonatomic, retain) NSTimer *timer;
self.timer = [[NSTimer timerWithTimeInterval:kAdsAppearTimeInterval target:self selector:@         


        

Answer 1

For a non-repeating timer, if you need a reference to the instance variable, I would not recommend a retain property in its declaration to avoid confusion.

setting the instance variable (myTimer)

 myTimer = [NSTimer scheduledTimerWithTimeInterval:myTimerInterval
                                            target:self
                                          selector:@selector(myTimerFired:)
                                          userInfo:nil
                                           repeats:NO];

when the timer fires, you can mark the instance variable as nil since its released when the timer is fired

- (void) myTimerFired: (NSTimer *) theTimer{

            myTimer = nil;
        //etc
    }

This way if you have to reference your instance variable (for example to disable the timer when exiting a View controller)

 -(void) onBack {
             if(myTimer){
                 [myTimer invalidate];
                 myTimer = nil;
              }
    }