UIViewController viewWillAppear not called when adding as subView

You should add statisticsController as a child view controller of the controller whose view you're adding it to.

self.statisticsController = [self.storyboard instantiateViewControllerWithIdentifier:@"StatisticsViewController"];self.statisticsController.match = self.match;[self.scrollView addSubview:self.statisticsController.view];[self addChildViewController:self.statisticsController];[self.statisticsController didMoveToParentViewController:self];

I'm not sure this will make viewDidAppear get called, but you can override didMoveToParentViewController: in the child controller, and that will be called, so you can put any code that you would have put in viewDidAppear in there.

I encounter -viewWillAppear: not called problem again. After googling, I came here. I did some tests, and find out that the calling order of -addSubview and -addChildViewController: is important.

Case 1. will trigger -viewWillAppear: of controller, but Case 2, it WON'T call -viewWillAppear:.

Case 1:

  controller?.willMoveToParentViewController(self)  // Call addSubview first  self.scrollView.addSubview(controller!.view)  self.addChildViewController(controller!)  controller!.didMoveToParentViewController(self)

Case 2:

  controller?.willMoveToParentViewController(self)  // Call adChildViewController first        self.addChildViewController(controller!)        self.scrollView.addSubview(controller!.view)  controller!.didMoveToParentViewController(self)

By default, appearance callbacks are automatically forwarded to children.It's determined with shouldAutomaticallyForwardAppearanceMethods property. Check value of this propery, if it's NO and if your child viewController should appear right on container's appearance, you should notify child with following methods in container's controller life-cycle implementation:

- (void)viewWillAppear:(BOOL)animated {    [super viewWillAppear:animated];    for (UIViewController *child in self.childViewControllers) {        [child beginAppearanceTransition:YES animated:animated];    }}- (void)viewDidAppear:(BOOL)animated {    [super viewDidAppear:animated];    [self.child endAppearanceTransition];}- (void)viewWillDisappear:(BOOL)animated {    [super viewWillDisappear:animated];    for (UIViewController *child in self.childViewControllers) {        [child beginAppearanceTransition:NO animated:animated];    }}- (void)viewDidDisappear:(BOOL)animated {    [super viewDidDisappear:animated];    [self.child endAppearanceTransition];}

Customizing Appearance and Rotation Callback Behavior

Fixed my problem! Hope it would be helpful.