Question

I’m wandering what is the correct way to do “long” actions in response to user events. For example, I have this slide to cancel block that animates itself off screen over 0.5 seconds. The [self coreDataAction] may take about 0.3 seconds itself.

I want to ensure that the action completes once the user sees the end of the animation ( I do not want the user to accidentally navigate to a different controller or close the app thinking that the action is done).

Where should I put the [self coreDataAction]; in this case? Above the block, within the block or in the completion block?

//should I put it here?

 CGPoint slideToCancelCenter = slideToCancel.view.center;
    [UIView animateWithDuration:0.5 animations:^{
        self.goToSleepButton.center = slideToCancelCenter;
        [UIView setAnimationDuration:0.5];
        CGPoint sliderCenter = slideToCancel.view.center;
        sliderCenter.y += slideToCancel.view.bounds.size.height;
        slideToCancel.view.center = sliderCenter;

//should I put it here?        
// [self coreDataAction];
    } completion:^(BOOL finished) {
//should I put it here?
    } ];

Answer 1

Assuming [self coreDataAction] executes on the main thread, I would say you should put it on the first line to ensure that the method is complete by the time the animation is done.