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.
Related
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 :)
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];
}
This one is tricky. I have a subclass of UINavigationController that overrides pop/push and present/dismiss methods. Here I customise the behaviour to set the correct size if the UINavigationController subclass is contained in a popover. Nothing too fancy, but I do it this way to don't write subclasses of all my ViewControllers and use Autolayout.
However, the completion blocks of the presentViewController:animated:completion: and dismissViewControllerAnimated:completion: are not being executed. And this is the weird part: the exact same code on iPhone works correctly, but on iPad is not executing the blocks. Here is a code sample.
#interface SBNavigationController : UINavigationController
#end
#implementation SBNavigationController
- (void) presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion
{
if ([viewControllerToPresent isKindOfClass:[UINavigationController class]])
{
UINavigationController *nav = (UINavigationController *) viewControllerToPresent;
[nav.topViewController setContentSizeForViewInPopover:kFullSizePopover];
} else
{
[viewControllerToPresent setContentSizeForViewInPopover:kFullSizePopover];
}
viewControllerToPresent.modalPresentationStyle = UIModalPresentationCurrentContext;
[super presentViewController:viewControllerToPresent animated:flag completion:completion];
}
- (void)dismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))completion ;
{
[super dismissViewControllerAnimated:flag completion:completion];
}
#end
And the code using it is this:
#implementation SBInviteFBContactViewController
...
- (void) createInviteByMailViewController
{
SBInviteMailViewController *mailInvite = [[SBInviteMailViewController alloc] initWithDelegate:self userInfo:_userInfo];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:mailInvite];
[self.navigationController presentViewController:navController
animated:YES
completion:^{
NSLog(#"presentViewController:");
}];
}
#pragma mark SBInviteMailProtocol
- (void) invitedMailContacts:(NSArray *)contacts;
{
[self.navigationController dismissViewControllerAnimated:YES
completion:^{
NSLog(#"animation Ended");
if (contacts) {
[self.delegate invitedMailContact:contacts];
[self popViewControllerAnimated:YES];
}
}];
}
...
#end
Any ideas?
This seems to be a huge bug. Please report it to Apple (and I am about to do the same). I found my way here because I just discovered the same bug myself, and did a google search to see if anyone else was talking about it.
I've created a very small demonstration project, whose architecture is like this:
ViewController - the main view controller
Its view contains a button Tap Me.
PopoverViewController - presented in popover
When you tap Tap Me in the main ViewController, it creates a UIPopoverController with this vc, PopoverViewController, as its content view controller; its view, too, contains a button Tap Me.
PopoverViewController2 - presented "modally" in same popover
PopoverViewController2 has its modalPresentationStyle set to UIModalPresentationCurrentContext so it can appear inside the popover. When you tap Tap Me in the popover, PopoverViewController calls presentViewController:....
Here's the code:
- (IBAction)doTapMe:(id)sender {
NSLog(#"about to present view controller");
[self presentViewController:[PopoverViewController2 new] animated:YES completion:^{
NSLog(#"in completion handler"); // never called!
}];
NSLog(#"did present view controller");
}
The log reads "about to present view controller" and "did present view controller", but "in completion handler" never appears, even though the "modal" view controller's view appears in the popover just fine.
(Moreover, changing to animated:NO not only doesn't fix it, it causes a visual glitch.)
The UIModalPrsentationCurrentContext style is only available if you are compiling against iOS 3.2 or greater. Can't imagine that is the issue though.
The docs for UIModalPrsentationCurrentContext also say:
When presenting a view controller in a popover, this presentation style is supported only if the transition style is UIModalTransitionStyleCoverVertical. Attempting to use a different transition style triggers an exception. However, you may use other transition styles (except the partial curl transition) if the parent view controller is not in a popover.
This is a strange one.
Any chance you're running a different version of iOS on the iPhone and the iPad?
I have a UIViewController then when I longpress to self.view it will push a popup (MenuViewController). But when I try to remove popup by removeFromSuperview it still appears
You can see more detail of my problem with this http://www.youtube.com/watch?v=nVVgmeJEnnY
ViewController.m
#import "MenuViewController.h"
#interface ViewController () {
MenuViewController *menu;
}
....
- (void)viewDidLoad
{
....
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(albumButtonPressed : ) name:#"albumButtonPressed" object:nil];
....
}
....
-(void)albumButtonPressed : (NSNotification*) notification {
UIImagePickerController *photoPicker = [[UIImagePickerController alloc] init];
photoPicker.delegate = self;
photoPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[self presentModalViewController:photoPicker animated:YES];
}
...
-(void)handleLongPress:(UILongPressGestureRecognizer*)recognizer {
menu = [[MenuViewController alloc] initWithNibName:#"MenuViewController" bundle:nil];
if (self.imageView.image != nil) {
menu.imageAdded = YES;
}
[self.view addSubview:menu.view];
}
MenuViewController.m
-(IBAction)albumButtonPressed:(id)sender {
[self.view removeFromSuperview];
[[NSNotificationCenter defaultCenter] postNotificationName:#"albumButtonPressed" object:nil];
}
Setting aside my reservations about not applying proper view controller containment, the problem is that your handleLongPress will be called multiple times with different recognizer.state values, once as UIGestureRecognizerStateBegan and again as UIGestureRecognizerStateEnded. You should be checking the state of the gesture, e.g.:
-(void)handleLongPress:(UILongPressGestureRecognizer*)recognizer {
if (recognizer.state == UIGestureRecognizerStateEnded) {
menu = [[MenuViewController alloc] initWithNibName:#"MenuViewController" bundle:nil];
if (self.imageView.image != nil) {
menu.imageAdded = YES;
}
[self.view addSubview:menu.view];
}
}
Original Answer:
I'd suggest putting a NSLog or breakpoint at your code with the removeFromSuperview and see if you're even getting to that piece of code.
There are some clear problems here. Specifically, you're not adding added the view associated MenuViewController in handleLongPress properly. If you want a subview with it's own controller, you have to use containment (and that only works with iOS 5 and later). And in containment, you have critical methods like addChildViewController, etc. See Creating Custom Container View Controllers in the View Controller Programming Guide or see WWDC 2011 - Implementing UIViewController Containment. And, as an aside, you're also maintaining a strong reference to MenuViewController, so even if you succeeded in removing it's view, you'd leak the controller.
Spend a little time going through the containment documentation/video, and I think you'll want to revisit how you're presenting your menu. This is dense reading, but worth really understanding. Containment is powerful, but has to be done right.
[self.view removeFromSuperview];
what do you mean by this?????? removing the main view!!!!
Instead of directly using
[self.view removeFromSuperview];
use
[[self.view.superview subviews] makeObjectsPerformSelector:#selector(removeFromSuperview) withObject:self.view];
I'm confused. I have a navigation controller with a BarItem which opens a first view. After some work is done, I want this view to disappear and I want a second view to open.
root view: navigation controller
first view: activity indicator, where some data is put together
second view: MFMailComposeViewController
In the root view, the BarItem runs these lines to open the first view:
IndicatorViewController *indicator = [[IndicatorViewController alloc] initWithNibName:#"IndicatorViewController" bundle:nil];
indicator.view.backgroundColor = [UIColor clearColor];
self.modalPresentationStyle = UIModalPresentationCurrentContext;
[self presentModalViewController:indicator animated:YES];
The first view (IndicatorViewController) does some work and finally runs
[self dismissModalViewControllerAnimated:YES];
This works fine. But - how do I open the second view?
I tried this:
I open the second view. After closing the second view, my first view pops up again (since it is still there) and get's dismissed at this point. This code is placed in the first view:
- (void) viewDidAppear:(BOOL)animated {
static BOOL firstTime = YES;
if (firstTime) {
//do stuff that takes some time (that's why I show the indicator)
MailViewController *controller = [[MailViewController alloc] init];
if (controller)
[self presentModalViewController:controller animated:YES];
firstTime = NO;
} else {
[self dismissModalViewControllerAnimated:YES];
}
}
Since the first view pops up again, the user can see the indicator one more time, after the second view is closed - and that is not what I want.
What am I missing here? What would be the better way to do this?
I would do something like this. Make a navigationController, and make the first view as the root controller. Then do something like this:
FirstView.m
- (void)viewDidLoad
{
[super viewDidLoad];
[self.navigationController setNavigationBarHidden:YES];
}
- (void) nextView { // however you get to your next view, button/action/etc.
UIViewController *screen = [self.storyboard instantiateViewControllerWithIdentifier:#"yourIdentifier"];
[self.navigationController pushViewController:screen animated:YES];
}
Then in the second view:
SecondView.m
- (void) nextView { // however you get to your next view, button/action/etc.
UIViewController *screen = [self.storyboard instantiateViewControllerWithIdentifier:#"yourIdentifier"];
[self.navigationController pushViewController:screen animated:YES];
}
And finally in the rootview:
RootView.m
- (void)viewDidLoad
{
[super viewDidLoad];
NSArray *navStack = [NSArray arrayWithObject:self];
self.navigationController.viewControllers = navStack;
[self.navigationController setNavigationBarHidden:NO];
}
This will make your RootView the new rootview of the NavigationController.
self.navigationController.viewControllers
is the array with all the ViewControllers that are on the navcontrollers stack. The first object is the rootcontroller. If we replace the whole array with our own array, it knows only one item. You CAN go back by dismissing if that's what you want though. This isn't the prettiest way of doing it, but it's not the worst either.