sequential blinking light animation in iOS

Question

Imagine an old fashion pinball machine (or similar) with three light bulbs on either side of the machine's top scoreboard panel. The bulbs are numbered 1-6

Id like to be able to call a method that will flash the lights on for .5 sec then off again passing in an array of numbers as the sequence in which the lights should flash

I wrote the below which does work but seems very inefficient and needlessly verbose. Im thinking that using a timer would be better but Im not sure how to make that work with my "sequence" array

Is there a better way to do this?

- (IBAction)testLights:(id)sender {

    NSArray *sequence = [[NSArray alloc] initWithObjects: [NSNumber numberWithInt:0], [NSNumber numberWithInt:1], [NSNumber numberWithInt:2], [NSNumber numberWithInt:3], [NSNumber numberWithInt:4],[NSNumber numberWithInt:5],nil];
    [self setLights:sequence];
}

- (void)setLights:(NSArray *)sequence {

    UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:0]integerValue]];
    light.alpha = 0;
    [UIView animateWithDuration:0.3f
                     animations:^{
                         light.alpha = 1;
                     }completion:^(BOOL finished){

                         //new annimation
                         light.alpha = 0;
                         UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:1]integerValue]];
                         [UIView animateWithDuration:0.3f
                                          animations:^{
                                              light.alpha = 1;
                                          }completion:^(BOOL finished){

                                              //new annimation
                                              light.alpha = 0;
                                              UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:2]integerValue]];
                                              [UIView animateWithDuration:0.3f
                                                               animations:^{
                                                                   light.alpha = 1;
                                                               }completion:^(BOOL finished){

                                                                   //new annimation
                                                                   light.alpha = 0;
                                                                   UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:3]integerValue]];
                                                                   [UIView animateWithDuration:0.3f
                                                                                    animations:^{
                                                                                        light.alpha = 1;
                                                                                    }completion:^(BOOL finished){

                                                                                        //new annimation
                                                                                        light.alpha = 0;
                                                                                        UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:4]integerValue]];
                                                                                        [UIView animateWithDuration:0.3f
                                                                                                         animations:^{
                                                                                                             light.alpha = 1;
                                                                                                         }completion:^(BOOL finished){

                                                                                                             //new annimation
                                                                                                             light.alpha = 0;
                                                                                                             UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:5]integerValue]];
                                                                                                             [UIView animateWithDuration:0.3f
                                                                                                                              animations:^{
                                                                                                                                  light.alpha = 1;
                                                                                                                              }completion:^(BOOL finished){

                                                                                                                                  light.alpha = 0;


                                                                                                                              }];


                                                                                                         }];


                                                                                    }];


                                                               }];



                                          }];


                     }];


}

Answer 1

This can be achieved by making the function recursive. I would suggest you pass the sequence object as an NSMutableArray.

- (void)setLights:(NSMutableArray *)sequence {

    if ([sequence count] > 0)
    {
        UIImageView *light=[lgtArray objectAtIndex: [[sequence objectAtIndex:0]integerValue]];
        [sequence removeObjectAtIndex:0];
        light.alpha = 0;
        [UIView animateWithDuration:0.3f
                         animations:^{
                             light.alpha = 1;
                         }completion:^(BOOL finished){

                             [self setLights:sequence];
                         }];
    }
}

This function would have an added advantage of being able to handle a sequence of any number, instead of just 6.