Animation subview removal freezes when scrolling - ios

Question

My code:
I am using the following code for an add to basket animation:
-(void)triggerAddItemAnimation:(NSIndexPath*)indexPath
{
//Cell that was pressed.
CellMenuItem *cell = [self.tableView cellForRowAtIndexPath:indexPath];
// grab the imageview using cell
UIImageView *imgV = (UIImageView*)[cell viewWithTag:IDENTIFIER_ANIMATION_IMAGE];
//Get the x-coordinate of the image.
int xCoord = cell.imgAddButton.frame.origin.x;
// get the exact location of image
CGRect rect = [imgV.superview convertRect:imgV.frame fromView:nil];
rect = CGRectMake(xCoord, (rect.origin.y*-1)-10, imgV.frame.size.width, imgV.frame.size.height);
//NSLog(#"rect is %f,%f,%f,%f",rect.origin.x,rect.origin.y,rect.size.width,rect.size.height);
// create new duplicate image
UIImageView *starView = [[UIImageView alloc] initWithImage:imgV.image];
[starView setFrame:rect];
starView.layer.cornerRadius=5;
starView.layer.borderColor=[[UIColor blackColor]CGColor];
starView.layer.borderWidth=1;
[self.view addSubview:starView];
// begin ---- apply position animation
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
pathAnimation.duration=0.65;
pathAnimation.delegate=self;
// tab-bar right side item frame-point = end point
CGPoint endPoint = CGPointMake(self.lblBasketItemsCount.frame.origin.x, self.lblBasketItemsCount.frame.origin.y);
CGMutablePathRef curvedPath = CGPathCreateMutable();
CGPathMoveToPoint(curvedPath, NULL, starView.frame.origin.x, starView.frame.origin.y);
CGPathAddCurveToPoint(curvedPath, NULL, endPoint.x, starView.frame.origin.y, endPoint.x, starView.frame.origin.y, endPoint.x, endPoint.y);
pathAnimation.path = curvedPath;
CGPathRelease(curvedPath);
// end ---- apply position animation
float animationDuration = 0.65f;
// apply transform animation
CABasicAnimation *basic=[CABasicAnimation animationWithKeyPath:#"transform"];
[basic setToValue:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.25, 0.25, 0.25)]];
[basic setAutoreverses:NO];
[basic setDuration:animationDuration];
[starView.layer addAnimation:pathAnimation forKey:#"curveAnimation"];
[starView.layer addAnimation:basic forKey:#"transform"];
//Remove the animation 0.05 before the animationDuration to remove clipping issue.
[starView performSelector:#selector(removeFromSuperview) withObject:nil afterDelay:animationDuration - 0.05f];
}
The Problem:
The animation works beautifully but when I scroll the image used for the animation (taken from the cell) does not remove from the view until the scrolling has stopped.
The subview being removed is removed with the last line of code within the method:
[starView performSelector:#selector(removeFromSuperview) withObject:nil afterDelay:animationDuration - 0.05f];
What I've tried:
Ive tried using GCD:
dispatch_async(dispatch_get_main_queue(), ^{
//call method here....
});
If I recall I believe Ive also tried a run loop with a timer, as well as perform selector on main thread.
Ive also tried putting the method in a block(not the actual code I used, merely an example):
[UIView animateWithDuration:0.5
delay:1.0
options: UIViewAnimationCurveEaseOut
animations:^{
}
completion:^(BOOL finished){
//Remove subview here
}];
The Question:
I can deduce that the scrolling is tying up the main thread, hence why I've tried to call the method asynchronously.
Can someone let me know what I'm doing wrong ?

Answer 1

To solve this issue you can use the complete portion of a block as can be seen above. I was simply using the block incorrectly at the time.
However the way I solved this, because I couldn't get a path animation to work in a block was to set the delegate of the animation to self.
And use the following:
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
[theView removeFromSuperview];
}