ios - How to reliably block duplicate animation calls in Objective-C? -

a user can initiate animation swipe gesture. want block duplicate calls animation, make sure once animation has started, cannot initiated again until has completed -- may happen if user accidentally swipes multiple times.

i imagine people achieve control using boolean flag (bool isanimatingflag) in manner shown @ bottom. i've done things before in apps many times -- never feel 100% whether flag guaranteed have value intend, since animation uses blocks , it's unclear me thread animation completion block being run on.

is way (of blocking duplicate animations) reliable multi-thread execution?

/* 'atomic' doesn't  * guarantee thread safety * i've set flag follows: * correct intended usage? */ @property (assign, nonatomic) bool isanimatingflag;  //…  @synthesize isanimatingflag  //…  -(void)starttheanimation{  // (1) return if isanimatingflag true if(self.isanimatingflag == yes)return;  /* (2) set isanimatingflag true * intention prevent duplicate animations * may caused unwanted double-tap */ self.etiisanimating = yes;       // (3) start new animation     [uiview animatewithduration:0.75 delay:0.0 options:nil animations:^{      // animations happen here...      } completion:^(bool finished) {      // (4) reset flag enable further animations         self.isanimatingflag = no;     }]; } 

disable gesture if don't want user triggering multiple times

- (void)starttheanimation:(id)sender {   [sender setenabled:no];    [uiview animatewithduration:0.75 delay:0.0 options:nil animations:^{      // animations happen here...    } completion:^(bool finished) {     [sender setenabled:yes];   }]; } 

update

gestures have enabled property use same idea if button , change it' enabled state