If I change the layout of a UICollectionView during an orientation change, I get EXC_BAD_ACCESS after a few rotations.
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
UICollectionViewLayout *layout = [[UICollectionViewFlowLayout alloc] init];
self.myCollectionView.collectionViewLayout = layout; // This causes EXC_BAD_ACCESS after a few rotations
}
Is this a UICollectionView bug? Or am I doing something wrong? If it's a bug, is there any way to change the whole layout during an orientation change?
I noticed that the same problem is mentioned in this answer. Debugging with NSZombies does not produce additional information.
Not quite sure it has something to do but the Release Notes for iOS 6 say:
The willRotateToInterfaceOrientation:duration:,
willAnimateRotationToInterfaceOrientation:duration:, and
didRotateFromInterfaceOrientation: methods are no longer called on any
view controller that makes a full-screen presentation over itself—for
example, presentViewController:animated:completion:
You should make sure that your apps are not using these methods to manage the layout of any subviews. Instead, they should use the view
controller’s viewWillLayoutSubviews method and adjust the layout using
the view’s bounds rectangle.
Since you are using UICollectionView maybe it has something to do that you are using this method to change its layout.
Related
I am trying to just do a simple view change for proof of concept.
here is the code
- (void)swipedScreen
{
if (self.secondView.superview == nil) {
[myView removeFromSuperview];
[self.view insertSubview:secondView atIndex:0];
}
}
when I swipe the screen what happens is the view area just goes black... and becomes unresponsive.
I started with a navigatoin app, replaced the tableview with just a standard uiviewcontroller class.. that worked fine..Then i added a secondView (xib only) and changed its class to match the viewcontroller of the first view.
The reason I am finding this difficult is because i am trying to animate the views inside the navigation controller and not push a whole view onto the stack which I am used to doing.
I'll bet that blank unresponsive view is, in reality, your secondView object. I always test by setting [secondView setBackgroundColor:[UIColor greenColor]] and checking if the massive green rectangle actually shows up.
EDIT: having looked at your code, there are multiple problems that arose:
You never actually +alloc or -init anything.
You never actually touch those nibs or make a reference to them in code
You declare two UIView's as IBOutlets and Strong (two exact opposites, as IBOutlets are __weak, __unsafe_unretained, or assign), yet do not link them to anything.
I've taken the liberty of revising it (sans nibs). Take a look.
Did you init the secondView? if init,you can try to set frame for the secondView
Your inserting the view at the bottom of the stack,
[self.view insertSubview:secondView atIndex:0];
Try using addSubview instead. Also you need to set the views frame somewhere.
while coding in iOS 4.3 before, I found while add a view controller's view to another view with [superview addSubView:controller.view], the controller instance will not receive the -viewWillAppear/viewDidAppear message, than I found same issue in some thread in stack overflow. After that, I manually call -viewWillAppear/-viewDidAppear as needed.
but, after upgrade to iOS 5.0, some frisky UIView behavior happened. Finally I found that in iOS 5, the [superview addSubView:controller.view] , will send a -viewWillAppear/-viewDidAppear message to the controller instance automatically, plus my manually calls, there are two duplicated message each time the controller action its behavior.
and I also found a similar issue: iOS 5 : -viewWillAppear is not called after dismissing the modal in iPad
Now, the problem is, after search apple's documents, I didn't find any explicitly doc for diff about these issues. I even wonder if this is a guaranteed view life cycle behavior in iOS 5.0 .
Does anyone fix similar issues or find some guidelines about these difference. cause I want to run my app both in 4.x & 5.x iOS.
In iOS 4 you had to manually call -viewWillAppear, -viewWillDisappear, etc. when adding or removing a view from your view hierarchy. These are called automatically in iOS 5 if the view is being added or removed from the window hierarchy. Fortunately, iOS 5 has a method in UIViewController that you can override to revert the behaviour back to how it worked with iOS 4. Just add this to your UIViewController:
-(BOOL)automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers {
return NO;
}
This is probably the easiest solution as long as you're supporting both iOS 4 and iOS 5. Once you drop support for iOS 4 you might consider modifying your code to use the newer approach when swapping views.
Edit 5 February 2012
Apparently this function requires the child view controller be added to the main view controller using the addChildViewController: method. This method doesn't exist in iOS4, so you need to do something like this:
if ([self respondsToSelector:#selector(addChildViewController:)] ) {
[self addChildViewController:childViewController];
}
Thanks to everyone who corrected me on this.
This may not be an answer what you want, but I had same kind of problem.
In my case, when I added a view controller's view to another view controller's view as a subview, the subview was received viewWillAppear only in iOS 5.0 not iOS 4.X.
So I added a nasty condition.
[self.view addSubview:self.viewController.view];
if ([[[UIDevice currentDevice] systemVersion] compare:#"5.0"] == NSOrderedAscending) {
[self.viewController viewWillAppear:animated];
}
From iOS 5.0, Apple provides a way to implement custom container view controllers like UINavigationController or UITabController. I think this change affects when viewWillAppear is called.
This problem may be solvable if we use -[UIViewController addChildViewController:].
The answers above a slightly incomplete.
Let's presume you have 2 view controllers, ControllerA, and ControllerB.
ControllerA.view is already added to the window(it is the parent), and you want to add ControllerB.view as a subview of ControllerA.
If you do not add ControllerB as a child of ControllerA first, the automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers will be ignored, and you will still be called by iOS5, meaning that you'll call your view controller callbacks twice.
Example in ControllerA:
- (BOOL)automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers {
return NO;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.controllerB = [[ControllerB alloc] initWithNibName:#"ControllerB" bundle:nil];
[self.view addSubview:self.controllerB.view];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.controllerB viewWillAppear:animated];
}
In ControllerB NSLogging in viewWillAppear:
- (void)viewWillAppear:(BOOL)animated
{
NSLog("#ControllerB will appear");
}
This will result in iOS5 only displaying that NSLog message twice. i.e. You're automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers has been ignored.
In order to fix this, you need to add controllerB as a child of controller a.
Back in ControllerA's class:
- (void)viewDidLoad
{
[super viewDidLoad];
self.controllerB = [[ControllerB alloc] initWithNibName:#"ControllerB" bundle:nil];
if ([self respondsToSelector:#selector(addChildViewController:)])
[self addChildViewController:self.controllerB];
[self.view addSubview:self.controllerB.view];
}
This will now work as expected in both iOS4 and iOS5 without resorting to the horrible hack of checking iOS version strings, but instead checking on if the function we're after is available.
Hope this helps.
It is iOS5 behavior:
viewWillAppear, viewDidAppear, ... are executed automatically after addSubView: for iOS5.
So for iOS5 no need to execute manually those methods as need for iOS<5.0.
The fix may be:
if ([[UIDevice currentDevice].systemVersion doubleValue] < 5.0) {
...execute viewWillAppear or other
}
By this method u know which os u use and put condition if is less then 5.0 or other one
[[UIDevice currentDevice] systemVersion]
view{Will,Did}Appear, view{Will,Did}Disappear are functions on View Controllers and not views. These functions are called by SDK provided view controllers that are supposed to manage other view controllers e.g. UITabBarController, UINavigationBarController.
If you are managing sub-view controllers yourself, you have to call these explicitly (and in proper order - though you should have a very good reason to do this). A modal view not getting these calls upon dismissal of a modal view is simply because there is no one there to call it. Encapsulate the root view controller in a UINavigationController (and hide the navigation bar if you like) and then open a modal view controller. Upon its dismissal, or pop, viewWillAppear will get called.
After reviewing all the evidence, I think the best thing to do is NOT use viewDidAppear etc for views that are affected by this ios 4 / ios 5 bug. Instead make a custom class (like viewDidAppearCustom) and call it yourself. this way you can guarantee that apple won't change the sdk again and mess you up. There is a great blog covering this issue here:
http://gamesfromwithin.com/view-controller-notification-changes-on-ios5
I am subclassing a UIView and overwrite the drawRect method. I'm noticing that the view's drawrect is only being called when the view first loads. After that it is never called again. How to I make sure it gets called after an orientation change? I've tried calling setNeedsDisplay on the view before and after the rotation and that doesn't do it.
[myView setContentMode:UIViewContentModeRedraw];
You can set this in IB as well (i.e., set mode to "redraw")
This was a bug related to something completely different. setNeedsDisplay does indeed cause drawRect to be called.
to answer this and the other 94,000 similiar questions about view rotation/drawrect funkiness,
-(id)initWithFrame:(CGRect)frame
{
if(self=[super initWithFrame:frame]) {
self.autoresizesSubviews=YES;
self.autoresizingMask=UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
}
return self;
}
I have a custom UIViewController, which is the only subView of UIView. The UIViewController contains delegate function:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
This function is called once when the application starts and is never called again when the device is rotated. I also notice that the willRotateToInterfaceOrientation function is never called. I pretty much commented out all the content in the UIViewController but it is still not responding to device rotation.
I ended up solving my own problem by starting from stretch to create a brand new UIViewController and made sure it was responsive to the device rotation. I then brought in my code piece by piece and checked the rotation. In the end, I found the root cause. In my custom UIViewController, I had
- (id)initWithFrame:(CGRect)theframe {
if (self.view = [super.view initWithFrame:theframe])
It worked find excpet it did not respond to device roation even though I did not call the init function. The solution is simple. Add [self init] in the initWithFrame function. Thank you all for responding.
Your code looks correct. I suspect it's something in your .xib file (like the wrong object type for "File's Owner"), so that perhaps your view controller subclass isn't being instantiated at all. Put some logging into viewDidLoad and make sure it's getting called.
Try doing a test app that just tests the rotation problem. This will help isolate your issue.
You may need to implement that method in the controller of the parent UIView, as it seems your view is enclosed in another view.
I am experiencing difficulties managing my view controller rotation.
Here is my app structure :
[Window]
---[addSubview:MainViewController.view]
My MainViewController's view contains an UIImageView which I need to rotate, this is my app background.
In my AppDelegate and MainController I overrided shouldAutorotateToInterfaceOrientation to return YES, but when I rotate my device nothing change. Even the status bar.
Should I manually apply transformation to my views when I receive UIDeviceOrientationDidChangeNotification ?
In IB I set resize subviews to YES in mainViewController.view.
So I am a little bit lost...
Thanks for your help.
thierry
Actually, you should override shouldAutorotateToInterfaceOrientation: — notice the colon, it's significant in ObjC — and only in the current view controller.
#implementation MainViewController
...
-(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
return YES;
}