CODEWITHSUNDEEP
iosobjective-cuinavigationcontrolleruiviewanimationtransition
Todd Anderson
Todd Anderson

Reputation: 1168

animationControllerForOperation not called after app goes to background

I have a viewcontroller with a custom navigation push transition using UINavigationControllerDelegate. Everything works perfectly when you start the animation, press the back button, etc.

However, if you push the viewcontroller onto the stack, background the app, return, then press back, the delegate method animationControllerForOperation is not called as it should be. during debugging, I have verified that self.navigationController.delegate is still properly set when we return app to foreground, but the delegate callback is never hit. Any ideas?

 //presenting vc
 - (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                              animationControllerForOperation:(UINavigationControllerOperation)operation
                                           fromViewController:(UIViewController*)fromVC
                                             toViewController:(UIViewController*)toVC
{
    if (operation == UINavigationControllerOperationPush) {
        _animationObject = [LVDashboardExplainerAnimation new];
        _animationObject.presenting = YES;
        return _animationObject;
    } else if (operation == UINavigationControllerOperationPop) {
        _animationObject.presenting = NO;
        return _animationObject;
    }
    return nil;
}

//other VC
- (void)headerTapped {
    self.navigationController.delegate = _navigationDelegate; //correct object
    [self.navigationController popViewControllerAnimated:YES];
}

Upvotes: 2

Views: 1882

Answers (1)

Todd Anderson
Todd Anderson

Reputation: 1168

The problem stemmed from manually calling viewWillAppear:animated when the app returned from being backgrounded. By calling this, the navigation delegate would call willShowViewController:animated: but not navigationController:animationControllerForOperation: or didShowViewController:animated:

For some reason, forcefully calling viewWillAppear throws the whole thing off. Even if we accounted for this and set the navigation delegate to nil, then back the the correct object, the functionality would not work correctly. I'm guessing this is a bug in the SDK, but for now we removed the forced call to viewWillAppear.

Upvotes: 1

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