change value during animation (SKAction) iOS

Question

I have the animation like below.

sit animation:

SKTexture *sit1 = [SKTexture textureWithImageNamed:@"sit_1_blur.png"];
SKTexture *sit2 = [SKTexture textureWithImageNamed:@"sit_2_blur.png"];
SKTexture *sit3 = [SKTexture textureWithImageNamed:@"sit_3_blur.png"];
SKTexture *sit4 = [SKTexture textureWithImageNamed:@"sit_4_blur.png"];
SKTexture *sit5 = [SKTexture textureWithImageNamed:@"sit_5_blur.png"];

NSArray *sitPng   = @[sit1,sit2,sit3];
NSArray *drinkPng = @[sit3,sit4,sit5];

sitAnimation   = [SKAction animateWithTextures:sitPng timePerFrame:0.2];
drinkAnimation = [SKAction animateWithTextures:drinkPng timePerFrame:1];


-(void) takeSit{
    [self runAction:sitAnimation completion:^{
        [self startDrink];
    }];
}

How can I change value every second during startDrink animation? Like so:

someValue +=0.2;

Answer 1

You need to have this inside your startDrink Animation (I am assuming startDrink is another action defined somewhere),

+ (SKAction *)customActionWithDuration:(NSTimeInterval)seconds actionBlock:(void (^)(SKNode *node, CGFloat elapsedTime))block;

measure the the time passed and update someValue +=0.2; accordingly.

Hope this helps.