UINavigationController hidesBarOnSwipe memory leak issue - ios

I've got a problem with hidesBarOnSwipe property of UINavigationController.
Overview :
Link to project file
I have one controller named FirstViewController which is root view of UINavigationController.
Everything is in Main.storyboard.
FirstViewController contains UIButton action. Inside that action I instantiate a SecondViewController and push it on a navigation stack.
- (IBAction)button:(id)sender {
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:#"SecondViewController"];
[self.navigationController pushViewController:vc animated:YES];
}
Inside SecondViewController there is only an hidesBarsOnSwipe property set to YES on viewDidLoad :
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationController.hidesBarsOnSwipe = YES;
}
and dealloc gets NSLogged :
- (void)dealloc {
NSLog(#"Dealloc");
}
Problem :
When we swipe up to hide navigationBar, dealloc is never get called. Instruments shows a SecondViewController memory leak here.
When we are on SecondViewController and we just press back button - everything is fine. Dealloc gets called.
There is definitly some kind of retain cycle but i have no idea why and how to avoid this kind of situation.

Some updates and temporary solution :
There is another method to perform navigationBar hiding.
What worked for me is to use :
[self.navigationController setNavigationBarHidden:hidden animated:YES];
To achieve good results add a property in your class to keep track status of navigationBar animation :
#property (assign, nonatomic) BOOL statusBarAnimationInProgress;
Implement UIScrollViewDelegate like this :
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat yVelocity = [scrollView.panGestureRecognizer velocityInView:scrollView].y;
if (yVelocity > 0 && !self.statusBarAnimationInProgress) {
[self setNavigationBarHidden:NO];
} else if (yVelocity < 0 && !self.statusBarAnimationInProgress) {
[self setNavigationBarHidden:YES];
}
}
Set navigation bar hidden should look like :
- (void)setNavigationBarHidden:(BOOL)hidden {
[CATransaction begin];
self.statusBarAnimationInProgress = YES;
[CATransaction setCompletionBlock:^{
self.statusBarAnimationInProgress = NO;
}];
[self.navigationController setNavigationBarHidden:hidden animated:YES];
[CATransaction commit];
}
I use CATransaction to check if animation of navigation bar is completed. Any way that works. Not so easy solution but at least there is no leak :)

Related

How do I push a view controller onto the nav stack from search results when presenting them modally?

I want to recreate the search UI shown in the iOS 7/8 calendar app. Presenting the search UI modally isn't a problem. I use UISearchController and modally present it just like the UICatalog sample code shows which gives me a nice drop down animation. The issue comes when trying to push a view controller from the results view controller. It isn't wrapped in a navigation controller so I can't push onto it. If I do wrap it in a navigation controller then I don't get the default drop down animation when I present the UISearchController. Any ideas?
EDIT:
I got it to push by wrapping my results view controller in a nav controller. However the search bar is still present after pushing the new VC onto the stack.
EDIT (2):
DTS from Apple said that the calendar app uses a non-standard method to push from search results. Instead they recommend removing focus from the search controller then pushing and returning focus on pop. This is similar to the way search in the settings app works I imagine.
Apple has gotten very clever there, but it's not a push, even though it looks like one.
They're using a custom transition (similar to what a navigation controller would do) to slide in a view controller which is embedded in a navigation controller.
You can spot the difference by slowly edge-swiping that detail view back and letting the previous view start to appear. Notice how the top navigation slides off to the right along with the details, instead of its bar buttons and title transitioning in-place?
Update:
The problem that you're seeing is that the search controller is presented above your navigation controller. As you discovered, even if you push a view controller onto a navigation controller's stack, the navigation bar is still beneath the search controller's presentation, so the search bar obscures any (pushed view controller's) navigation bar.
If you want to show results on top of the search controller without dismissing it, you'll need to present your own modal navigation view controller.
Unfortunately, there's no transition style which will let you present your navigation controller the same way the built-in push animation behaves.
As I can see, there are three effects that need to be duplicated.
The underlying content dims, as the presented view appears.
The presented view has a shadow.
The underlying content's navigation completely animates off-screen, but its content partially animates.
I've reproduced the general effect within an interactive custom modal transition. It generally mimic's Calendar's animation, but there are some differences (not shown), such as the keyboard (re)appearing too soon.
The modal controller that's presented is a navigation controller. I wired up a back button and edge swipe gesture to (interactively) dismiss it.
Here are the steps that are involved:
In your Storyboard, you would change the Segue type from Show Detail to Present Modally.
You can leave Presentation and Transition set to Default, as they'll need to be overridden in code.
In Xcode, add a new NavigationControllerDelegate file to your project.
NavigationControllerDelegate.h:
#interface NavigationControllerDelegate : NSObject <UINavigationControllerDelegate>
NavigationControllerDelegate.m:
#interface NavigationControllerDelegate () <UIViewControllerTransitioningDelegate>
#property (nonatomic, weak) IBOutlet UINavigationController *navigationController;
#property (nonatomic, strong) UIPercentDrivenInteractiveTransition* interactionController;
#end
- (void)awakeFromNib
{
UIScreenEdgePanGestureRecognizer *panGestureRecognizer = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePan:)];
panGestureRecognizer.edges = UIRectEdgeLeft;
[self.navigationController.view addGestureRecognizer:panGestureRecognizer];
}
#pragma mark - Actions
- (void)handlePan:(UIScreenEdgePanGestureRecognizer *)gestureRecognizer
{
UIView *view = self.navigationController.view;
if (gestureRecognizer.state == UIGestureRecognizerStateBegan)
{
if (!self.interactionController)
{
self.interactionController = [UIPercentDrivenInteractiveTransition new];
[self.navigationController dismissViewControllerAnimated:YES completion:nil];
}
}
else if (gestureRecognizer.state == UIGestureRecognizerStateChanged)
{
CGFloat percent = [gestureRecognizer translationInView:view].x / CGRectGetWidth(view.bounds);
[self.interactionController updateInteractiveTransition:percent];
}
else if (gestureRecognizer.state == UIGestureRecognizerStateEnded)
{
CGFloat percent = [gestureRecognizer translationInView:view].x / CGRectGetWidth(view.bounds);
if (percent > 0.5 || [gestureRecognizer velocityInView:view].x > 50)
{
[self.interactionController finishInteractiveTransition];
}
else
{
[self.interactionController cancelInteractiveTransition];
}
self.interactionController = nil;
}
}
#pragma mark - <UIViewControllerAnimatedTransitioning>
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)__unused presented presentingController:(UIViewController *)__unused presenting sourceController:(UIViewController *)__unused source
{
TransitionAnimator *animator = [TransitionAnimator new];
animator.appearing = YES;
return animator;
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)__unused dismissed
{
TransitionAnimator *animator = [TransitionAnimator new];
return animator;
}
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForPresentation:(id<UIViewControllerAnimatedTransitioning>)__unused animator
{
return nil;
}
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)__unused animator
{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wgnu-conditional-omitted-operand"
return self.interactionController ?: nil;
#pragma clang diagnostic pop
}
The delegate will provide the controller with its animator, interaction controller, and manage the screen edge pan gesture to dismiss the modal presentation.
In Storyboard, drag an Object (yellow cube) from the object library to the modal navigation controller. Set its class to ourNavigationControllerDelegate, and wire up its delegate and navigationController outlets to the storyboard's modal navigation controller.
In prepareForSegue from your search results controller, you'll need to set the modal navigation controller's transitioning delegate and modal presentation style.
navigationController.transitioningDelegate = (id<UIViewControllerTransitioningDelegate>)navigationController.delegate;
navigationController.modalPresentationStyle = UIModalPresentationCustom;
The custom animation that the modal presentation performs is handled by transition animator.
In Xcode, add a new TransitionAnimator file to your project.
TransitionAnimator.h:
#interface TransitionAnimator : NSObject <UIViewControllerAnimatedTransitioning>
#property (nonatomic, assign, getter = isAppearing) BOOL appearing;
TransitionAnimator.m:
#implementation TransitionAnimator
#synthesize appearing = _appearing;
#pragma mark - <UIViewControllerAnimatedTransitioning>
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
return 0.3;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
// Custom animation code goes here
}
The animation code is too long to provide within an answer, but it's available in a sample project which I've shared on GitHub.
Having said this, the code, as it stands, was more of a fun exercise. Apple has had years to refine and support all their transitions. If you adopt this custom animation, you may find cases (such as the visible keyboard) where the animation doesn't do what Apple's does. You'll have to decide whether you want to invest the time to improve the code to properly handle those cases.
I know this thread is old, but there seems to be a much simpler approach to getting the desired behavior.
The important thing to realize is the UISearchController is presented from the source controller, which is a view controller inside the navigation controller. If you inspect the view hierarchy, you see that the search controller, unlike regular modal presentations, isn't presented as a direct child of the window, but rather as a subview of the navigation controller.
So the general structure is
UINavigationController
MyRootViewController
UISearchViewController (presented pseudo-"modally")
MyContentController
Essentially you just need to get from the MyContentController up to the MyRootViewController, so you can access its navigationController property. In my tableView:didSelectRowAtIndexPath: method of my search content controller, I simply use the following to access my root view controller.
UINavigationController *navigationController = nil;
if ([self.parentViewController isKindOfClass:[UISearchController class]]) {
navigationController = self.parentViewController.presentingViewController.navigationController;
}
From there you can easily push something onto the navigation controller, and the animation is exactly what you'd expect.
EDIT: an alternate solution that doesn't rely on a UIWindow. I think the effect is very similar to the calendar app.
#interface SearchResultsController () <UINavigationControllerDelegate>
#end
#implementation SearchResultsController
- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// this will be the UINavigationController that provides the push animation.
// its rootViewController is a placeholder that exists so we can actually push and pop
UIViewController* rootVC = [UIViewController new]; // this is the placeholder
rootVC.view.backgroundColor = [UIColor clearColor];
UINavigationController* nc = [[UINavigationController alloc] initWithRootViewController: rootVC];
nc.modalPresentationStyle = UIModalPresentationCustom;
nc.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[UIView transitionWithView: self.view.window
duration: 0.25
options: UIViewAnimationOptionTransitionCrossDissolve | UIViewAnimationOptionAllowAnimatedContent
animations: ^{
[self.parentViewController presentViewController: nc animated: NO completion: ^{
UIViewController* resultDetailViewController = [UIViewController alloc];
resultDetailViewController.title = #"Result Detail";
resultDetailViewController.view.backgroundColor = [UIColor whiteColor];
[nc pushViewController: resultDetailViewController animated: YES];
}];
}
completion:^(BOOL finished) {
nc.delegate = self;
}];
}
- (void) navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
// pop to root? then dismiss our window.
if ( navigationController.viewControllers[0] == viewController )
{
[UIView transitionWithView: self.view.window
duration: [CATransaction animationDuration]
options: UIViewAnimationOptionTransitionCrossDissolve | UIViewAnimationOptionAllowAnimatedContent
animations: ^{
[self.parentViewController dismissViewControllerAnimated: YES completion: nil];
}
completion: nil];
}
}
#end
ORIGINAL solution:
Here's my solution. I start out using the same technique you discovered in the UICatalog example for showing the search controller:
- (IBAction)search:(id)sender
{
SearchResultsController* searchResultsController = [self.storyboard instantiateViewControllerWithIdentifier: #"SearchResultsViewController"];
self.searchController = [[UISearchController alloc] initWithSearchResultsController:searchResultsController];
self.searchController.hidesNavigationBarDuringPresentation = NO;
[self presentViewController:self.searchController animated:YES completion: nil];
}
In my example, SearchResultsController is a UITableViewController-derived class. When a search result is tapped it creates a new UIWindow with a root UINavigationController and pushes the result-detail view controller to that. It monitors for the UINavigationController popping to root so it can dismiss the special UIWindow.
Now, the UIWindow isn't strictly required. I used it because it helps keep the SearchViewController visible during the push/pop transition. Instead, you could just present the UINavigationController from the UISearchController (and dismiss it from the navigationController:didShowViewController: delegate method). But modally-presented view controllers present on an opaque view by default, hiding what's underneath. You could address this by writing a custom transition that would be applied as the UINavigationController's transitioningDelegate.
#interface SearchResultsController () <UINavigationControllerDelegate>
#end
#implementation SearchResultsController
{
UIWindow* _overlayWindow;
}
- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// this will be the UINavigationController that provides the push animation.
// its rootViewController is a placeholder that exists so we can actually push and pop
UINavigationController* nc = [[UINavigationController alloc] initWithRootViewController: [UIViewController new]];
// the overlay window
_overlayWindow = [[UIWindow alloc] initWithFrame: self.view.window.frame];
_overlayWindow.rootViewController = nc;
_overlayWindow.windowLevel = self.view.window.windowLevel+1; // appear over us
_overlayWindow.backgroundColor = [UIColor clearColor];
[_overlayWindow makeKeyAndVisible];
// get this into the next run loop cycle:
dispatch_async(dispatch_get_main_queue(), ^{
UIViewController* resultDetailViewController = [UIViewController alloc];
resultDetailViewController.title = #"Result Detail";
resultDetailViewController.view.backgroundColor = [UIColor whiteColor];
[nc pushViewController: resultDetailViewController animated: YES];
// start looking for popping-to-root:
nc.delegate = self;
});
}
- (void) navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
// pop to root? then dismiss our window.
if ( navigationController.viewControllers[0] == viewController )
{
[_overlayWindow resignKeyWindow];
_overlayWindow = nil;
}
}
#end
As you present a viewController the navigationController becomes unavailable. So you have to dismiss your modal first and then push another viewController.
UISearchController must be rootViewController of a UINavigationController and then you present navigation controller as modal.

iOS: change view from viewDidAppear

I'm playing around with view life cycles & am having trouble changing a view from the load of a different view.
In my ViewController.h i have:
-(void)viewDidAppear:(BOOL)animated{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
ViewController2 *viewController = (ViewController2 *)[storyboard instantiateViewControllerWithIdentifier:#"ViewController2"];
[self presentViewController:viewController animated:YES completion:nil];
}
However this only causes the view to be between ViewController, and ViewController2 appearing with animation (in a loop).
I used the code in viewDidLoad however neither of the view's loaded (from reading you cannot change view until the viewWillAppear)
Update: When using the code in viewWillAppear, whose view is not in the window hierarchy error is thrown.
How does one change the view from view setup stage?
Update
Using the above code, inside & out of GCD, in viewDidLoad, viewWillAppear & viewDidAppear either results in an infinite loop of animated showing of the ViewController2, or crash on 2nd attempt of segue (result from the loop).
EDITED:
I'm not sure exactly what you're trying to do, but assuming you are wanting the first viewcontroller to appear and then the second viewcontroller to immediately animate on top of the first one, you should be able to accomplish using several options:
First you could just wrap your calls in a dispatch_async call:
dispatch_async(dispatch_get_main_queue(), ^{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
ViewController2 *viewController = (ViewController2 *)[storyboard
instantiateViewControllerWithIdentifier:#"ViewController2"];
[self presentViewController:viewController animated:YES completion:nil];
});
Or you could use a show modally segue:
- (void)viewDidLoad {
[super viewDidLoad];
dispatch_async(dispatch_get_main_queue(), ^{
[self performSegueWithIdentifier:#"myModalSegue" sender:self];
});
}
Or you could use a navigation controller and use a standard show segue (formally push). This one doesn't require the dispatch_async:
- (void)viewDidLoad {
[super viewDidLoad];
[self performSegueWithIdentifier:#"myshowsegue" sender:self];
}
I've posted working examples of all three on: github
It is better to exchange views in loadView method.
- (void)loadView {
CGRect rect = [[UIScreen mainScreen] applicationFrame];
MyView *view = [[MyView alloc] initWithFrame:rect];
[view setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth];
self.view = view;
}

UIScrollView disabled after UINavigationController push and pop

I have looked at the other answers to this question, and none of them have helped.
I have a UIScrollView in my very simple scene, embedded like this:
I use this code to make sure the scroll view will actually scroll, based off of this answer.
-(void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self resizeScrollView];
}
- (void) viewDidLayoutSubviews {
[self resizeScrollView];
}
- (void)resizeScrollView
{
_scrollView.scrollEnabled = YES;
[_scrollView setContentSize:_innerView.frame.size];
}
- (IBAction)cameraButtonPressed:(id)sender {
UIViewController *vc = [UIViewController new];
[self.navigationController pushViewController:vc animated:YES];
}
The problem is that scrolling doesn't work after I've pushed and popped the new ViewController (Which originally was an image picker btw).
I don't know why this worked, but I wrapped everything in another view, and it's perfect now.

UIView not showing after hiding once

I have a UIView named scoreView on ViewController. When I load the ViewController I hide the scoreView in the viewDidLoad method. It works fine.
- (void)viewDidLoad{
[super viewDidLoad];
self.navigationController.navigationBarHidden = YES;
scoreView.hidden = YES;
}
Then after being pushed from another view controller to this ViewController, I call a method, where I want to show the scoreView. But the scorView is still being hidden. Where is the mistake I am doing?
-(void)levelCompleteViewAppear: (NSString *)score{
NSLog(#"This method is called!");
scoreView.hidden = NO ;
[gameScore setText:score];
}
This is how I am pushing to the ViewController from anothe view controller.
-(void)levelComplete{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle: nil];
ViewController *vc = [storyboard instantiateViewControllerWithIdentifier:#"ViewController"];
[self.navigationController pushViewController:vc animated:YES];
[vc levelCompleteViewAppear:scoreLabel.text];
}
Try This,
-(void)viewDidLoad
{
[super viewDidLoad];
[self.view addSubview:scrollview];
[self.view bringSubviewToFront:scrollview];
}
When you are pushing the viewController to navigationController, it will not call viewDidLoad directly. If you want to make it visible, write it down in viewWillAppear or vieDidAppear method.
- (void) viewWillAppear{
scoreView.hidden = YES;
}
add this in your code
If first time ViewController class in opeining then ViewDidLoad will call but if you are coming back from some other ViewController then ViewDidLoad wont get call for that you need to show your View in ViewWillAppear Or ViewDidAppear.
Suppose you called Class A then ViewDidLoad will get call then again you moved class B then class B viewDidLoad will get call but if you are coming back again to class A then your viewDidLoad wont get call, it will call ViewWillAppear and viewDidAppear.
Hope it may clear you more.
-(void)viewWillApper:(BOOL)animated{
scoreView.hidden = NO ;
}

NavigationBar Hidding issue on Back

On View1 I hide the navigationBar in viewDidLoad:
- (void)viewDidLoad
{
[super viewDidLoad];
[self.navigationController setNavigationBarHidden:YES];
}
Then I navigate to View2 where I show the navigationBar
- (void)viewDidLoad
{
[super viewDidLoad];
[self.navigationController setNavigationBarHidden:NO];
self.title = #"Title";
}
But on back to View1 again, the navigationBar doesn't hide, even if I did tried to hide it after the pushViewController in View2
[self.navigationController pushViewController:View1 animated:YES];
[self.navigationController setNavigationBarHidden:YES];
I also tried to hide the navigation from viewWillAppear in View1 and it hides it, but there is an ugly delay and I don't find it as a good practice.
So can anyone help me with this issue, how can I hide correctly the navigationBar on back to View1?
The best practice to do what you want is putting bellow in your first viewController:
- (void)viewWillAppear:(BOOL)animated{
[self.navigationController setNavigationBarHidden:YES animated:animated];
[super viewWillAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated{
[self.navigationController setNavigationBarHidden:NO animated:animated];
[super viewWillDisappear:animated];
}
-(void) viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self.navigationController setNavigationBarHidden:YES];
}
The ViewController1 is not going to get allocated again and so viewDidLoad is not going to get called.
You can do it in viewWillAppear though. But if you are saying that there is a delay, you can do one more thing.
You can get the reference ofViewController1 in ViewController2. Suppose ViewController1 is the first controller in the navigation controller, then do this:
//ViewController2.m
- (IBAction)backButtonPressed:(id)sender{
ViewController1 *view1 = [self.navigationController.viewControllers objectAtIndex:0];
[view1.navigationController setNavigationBarHidden:YES];
Your code is correct, but you need to write like this:
[self.navigationController setNavigationBarHidden:YES];
first, then write
[self.navigationController pushViewController:View1 animated:YES];
See when you are pushing View2 from View2 in navigation stack than View1 doesn't gets deallocated. it is there in in the stack. So when you popping out View2 that time View1 viewDidLoad won't get called. so your code setNavigationBarHidden to hide navigation bar doesn't executes. So put that code to ViewWillAppear or ViewDidAppear because these methods gets called every time View appears.
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:YES];
}

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