ios - How to wait for an repeating CAAnimation to finish a cycle before removing it -

i have view let pulsate using caanimation.

cakeyframeanimation *animation = [cakeyframeanimation animationwithkeypath:@"opacity"]; animation.values = @[ @0.0f, @1.0f, @0.0f ]; animation.duration = 0.5; animation.repeatcount = huge_valf;  [view.layer addanimation:animation forkey:@"pulsate"]; 

when remove animation using [view.layer removeanimationforkey:@"pulsate"] opacity snaps immediately. achieve executing pulsating animation finished , animation removed.

i tried setting repeatcount 1, throws exception because animation immutable.

also tried getting current value presentation layer , applying model, removing animation , again adding animation finish it. gives noticeable hiccups when stopping animation , timing off usually.

is there way let animation finish running cycle , remove afterwards?

there's lot of details right, general idea create non-repeating animation removed on completion, , use animationdidstop delegate method restart animation.

the first item of business declare properties

@property (weak, nonatomic) iboutlet uiimageview *orangeview2; @property (nonatomic) bool pulseactive; @property (strong, nonatomic) cakeyframeanimation *pulseanimation; 

the first property view animated, second keeps track of whether animation enabled, , last actual animation (stored in property have instantiate once).

next, we'll use lazy instantiation create animation object

- (cakeyframeanimation *)pulseanimation {     if ( !_pulseanimation )     {         _pulseanimation = [cakeyframeanimation animationwithkeypath:@"opacity"];         _pulseanimation.values = @[ @0.0f, @1.0f, @0.0f ];         _pulseanimation.duration = 0.5;          _pulseanimation.delegate = self;         [_pulseanimation setvalue:@"pulseanimation" forkey:@"animationidentifier"];     }      return( _pulseanimation ); } 

the important bits here

• the animation not repeat (by default)
• the animation removedoncompletion (by default)
• the delegate set self animationdidstop method called
• the animation given identifier using setvalue:forkey:

that last item needed if multiple animations using same delegate, since in case, you'll need way determine animation called animationdidstop. strings passed forkey , setvalue arbitrary, , stored in dictionary in animation object.

ok, need implement animationdidstop. implementation checks pulseactive property , restarts animation if necessary (after checking identity of animation).

- (void)animationdidstop:(caanimation *)animation finished:(bool)flag {     nsstring *animationidentifier = [animation valueforkey:@"animationidentifier"];      if ( [animationidentifier isequaltostring:@"pulseanimation"] )     {         if ( self.pulseactive )             [self.orangeview2.layer addanimation:self.pulseanimation forkey:@"pulsate"];     } } 

all that's left start , stop animation. example, button toggles animation

- (ibaction)pulsebuttonpressed {     if ( !self.pulseactive )     {         self.pulseactive = yes;         [self.orangeview2.layer addanimation:[self pulseanimation] forkey:@"pulsate"];     }     else     {         self.pulseactive = no;     } }