Best way to refactor this loop of animations with delay?

Question

I have some animations happening after some delay calls the code to animate. It works fine, but the code to call the functions is not nice.

 double delayInSeconds = 0.2;
 dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.1 * NSEC_PER_SEC);
 dispatch_time_t popTime2 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.2 * NSEC_PER_SEC);
 dispatch_time_t popTime3 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.3 * NSEC_PER_SEC);
 dispatch_time_t popTime4 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.4 * NSEC_PER_SEC);
 dispatch_time_t popTime5 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.5 * NSEC_PER_SEC);
 dispatch_time_t popTime6 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.6 * NSEC_PER_SEC);
 dispatch_time_t popTime7 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.7 * NSEC_PER_SEC);
 dispatch_time_t popTime8 = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds + 0.8 * NSEC_PER_SEC);
 if (self.menuType == kRacingMenu) {
 self.menuAnimationSequence = @[@0, @1, @3, @2, @4]; //animation sequence!
 dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:0];
 });
 dispatch_after(popTime2, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:1];
 });
 dispatch_after(popTime3, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:2];
 });
 dispatch_after(popTime4, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:4];
 });
 dispatch_after(popTime5, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:3];
 });
 }else if (self.menuType == kLoginMenu) {
 self.menuAnimationSequence = @[@0, @1, @3, @2]; //animation sequence!
 dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:0];
 });
 dispatch_after(popTime2, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:1];
 });
 dispatch_after(popTime3, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:2];
 });
 dispatch_after(popTime4, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:3];
 });
 } else {
 [self animateWithCoreAnimaGenerallyWithIndex:1];
 dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:0];
 });
 dispatch_after(popTime2, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:2];
 });
 dispatch_after(popTime3, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:4];
 });
 dispatch_after(popTime4, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:3];
 });
 dispatch_after(popTime5, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:5];
 });
 dispatch_after(popTime6, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:7];
 });
 dispatch_after(popTime7, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:6];
 });
 dispatch_after(popTime8, dispatch_get_main_queue(), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:8];
 });
 }

How best to abstract this timer? And the calls to start the animation?

• Flambino: animateWithCoreAnimaGenerallyWithIndex:? Find & replace error or your own method?
• manuelBetancurt: @Flambino, Hi thanks, didn't understand your question, I got no error, was this the question?
• JeffRegan: It looks like you can accomplish a lot of this with a for loop and an incremented delay variable passed to a UIView animation block.
• Flambino: What I meant was that animateWithCoreAnimaGenerallyWithIndex: doesn't sound like a real method name. I mean, "AnimaGenerally"? It just seemed like it might be a mistake. But if you have a method that's called that, then OK - it's just a really strange method name.

Answer 1

Anything that you're using as a constant should be marked as such.

double const delayInSeconds = 0.2f;

---

Now then, we know in Objective-C, we have NSArray and its mutable cousin, and they can only hold objects. But also remember, Objective-C is a superset of C. We can use a C-Style array.

int const POPTIME_COUNT = 8;
dispatch_time_t poptime[POPTIME_COUNT];

And then fill this an array with a loop...

for (int i = 0; i < POPTIME_COUNT; ++i) {
 double totalDelay = delayInSeconds + ((i + 1) * 0.1 * NSEC_PER_SEC) 
 poptime[i] = dispatch_time(DISPATCH_TIME_NOW, totalDelay);
}

---

Firing off the animations is done just as easily in a loop:

for (int i = 0; i < NUM_ANIMATIONS; ++i) {
 dispatch_after(poptime[i], dispatch_get_main_queue()), ^(void){
 [self animateWithCoreAnimaGenerallyWithIndex:i];
 }];
}

Where NUM_ANIMATIONS is the number of animations you need to fire off (it's different in each branch).