UPDATE: See my answer to this question first. This appears to be a bug. A minimal test case has been created and a report has been filed with Apple. (Fixed as of iPhone OS 3.1.)
Here's a puzzler from the "I'm so close!" department.
I have a Tab Bar-based iPhone app. Each tab features a UINavigationController with the usual suspects (nav bar, table view ... which in turn can lead to another VC, etc.).
Now, one of those lower-level VCs is to be used in portait and landscape modes. But there's a problem. Our landscape-friendly VC's shouldAutorotateToInterfaceOrientation: won't get called out-of-the-box! What to do?
Here's what we do. In my Tab Bar Controller, which I have implemented in its own file, I have this:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return [self.selectedViewController shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}
This ends up propagating the request to my landscape-friendly VC, which also responds to this message. All my other VCs don't implement this method, so they simply go with the default portrait orientation.
Problem solved!!! Yay!
Well, not quite. :(
Seems like things don't go so well when my landscape-friendly VC is invoked from within the depths of the tab bar controller's MoreNavigationController.
I decided to compare/contrast between a VC called from within one of the first four tab bar UINavigationControllers ... and that same VC called from within the MoreNavigationController. This is going to be a bit ultra-detailed, so bear with me. Hopefully the play by play proves useful for sleuthing things out.
When the app loads, there are several initial calls to the tab bar controller's shouldAutorotate... method. In these early cases, selectedViewController is nil. However, we eventually finish loading, the initial tab item is selected, and all is well.
Right. First, let's pick one of the first four tab bar items and drill down to our VC.
We'll pick third nav bar item, so that's the third nav controller. We drill down to our VC that supports rotation. A quick inspection confirms that the parent is indeed the third nav controller from our tab bar's view controller list. Good!
Let's rotate the device. The tab bar controller is asked to autorotate (see the above code). We observe that selectedViewController is also that third nav controller, plus the nav controller's top and visible view controllers are both set to our trusty VC that supports rotation.
Thus, the tab bar controller will forward the shouldAutorotate message over to the third nav controller ... but our rotation-friendly VC ultimately gets the message. (I'm not doing anything special here. Maybe the desired VC gets the message because it's the top and/or visible VC?) In any event, we rotate to landscape, things are resized, and all is well. "Great Success!"
Now let's hit that back button and pop the VC stack, leaving landscape mode in the process. The tab bar controller is queried again.
Time for a little aside here. The topViewController for our nav controller is still that rotation-friendly VC, but visibleViewController is now set to UISnapshotModalViewController! Heh. Never saw this one before ... but Erica Sadun has. Looks like it's for "disappearing view controllers" (which in this case is certainly true - it's disappearing alright).
As I keep stepping through, the visible VC stays as Snapshot, but the top VC eventually changes to the next VC on the stack, since my special VC is eventually gone. Fair enough.
So that's the scenario where everything works well.
Now let's try the same test, only this time we're going to go to the MoreNavigationController (the More tab bar item) and drill down to the same VC class as before. In my case it happens to be the 7th one in the tab bar controller's VC list.
We enter the rotation-aware VC and ... this time it gets asked to rotate directly! The Tab Bar Controller is not asked for permission to rotate at all. Hmm.
A quick check of the parent VC shows it is a MoreNavigationController. OK, that makes sense.
Now let's try to rotate the device. NOTHING GETS CALLED. None of our breakpoints get hit. Not in our VC. Not in our tab bar controller. (Huh?!?!)
O-kaaaay. Let's pop the stack, go back into the same VC and try to rotate again. Weird. NOW we get a call in the Tab Bar Controller asking for autorotation permission. Here, the selected Controller is our trusty Nav controller (#7), but this time its visibleViewController and topViewController are SET TO NIL!
Once we continue from here, a mysterious message appears in the debugger console:
Using two-stage rotation animation. To
use the smoother single-stage
animation, this application must
remove two-stage method
implementations.
Mysterious because I'm not using two-stage rotation animation! No SecondHalf method variants are in play anywhere in my source code.
Alas, my rotation-aware VC is never told that rotation is occurring (even though rotation does occur on-screen), so of course my view is all fouled up as a result. Mayhem and sadness ensue. :(
We won't even bother popping the stack at this point.
I think the View Controller doc hints at the possible problem:
If you want to perform custom
animations during an orientation
change, you can do so in one of two
ways. Orientation changes used to
occur in two steps, with notifications
occurring at the beginning, middle,
and end points of the rotation.
However, in iPhone OS 3.0, support was
added for performing orientation
changes in one step. Using a one-step
orientation change tends to be faster
than the older two-step process and is
generally recommended for any new
code.
I wonder if MoreNavigationController is still responding to the two-step process, and is thus tripping up any attempts to use the one-step process? Note that, if you respond to the two-step messages, the one-step variant will not work (again, per the docs). I'm not responding to them, but I have a sneaking suspicion something behind-the-scenes IS.
In fact, if I comment out the single-step method, and try to respond to willAnimateSecondHalfOfRotationFromInterfaceOrientation:duration:, I do get the memo! But it still doesn't pop off the stack very cleanly (in terms of visuals). Even stranger: willAnimateFirstHalfOfRotationFromInterfaceOrientation:duration: is NOT called, even when I tried to sneak a call to self (using the FirstHalf message) in shouldAutorotateToInterfaceOrientation:. It returns immediately during a trace, as if I never even defined it. Sigh.
So that's the play-by-play.
In summary, has anyone successfully handled one-step device rotation for a VC invoked from within a Tab Bar Controller's MoreNavigationController? Inquiring minds want to know!
Apple advises against subclassing UITabBarController, so I found an easy way to handle autorotation using categories instead. It doesn't fix your bug with the More... view controllers, but I think it's a more Apple-friendly way of getting the job done (and means less subclassing for you).
To make every tab in my application autorotate properly, I've defined -shouldAutorotateToInterfaceOrientation: in my custom view controllers, but they are all inside UINavigationControllers within a UITabBarController, so the message won't get sent down the chain to my VC until those two also respond. So I added the following lines to my app delegate files:
Added to the bottom of MyAppDelegate.h
#interface UITabBarController (MyApp)
#end
#interface UINavigationController (MyApp)
#end
Added to the bottom of MyAppDelegate.m
#implementation UITabBarController (MyApp)
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
return YES;
}
#end
#implementation UINavigationController (MyApp)
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
return YES;
}
#end
It appears we have a bug. I have created a reproducible, minimal test case, and reported it via Apple Bug Reporter (RADAR Problem 7139857).
Update: This has been fixed as of iPhone OS 3.1.
The essential problem is:
View controllers already on a
Navigation Controller stack do not
receive
willAnimateRotationToInterfaceOrientation:duration:
messages when a Tab Bar Controller's
'More Navigation Controller' is in
use.
This problem does not occur when the tab bar item view controllers are basic view controllers. Only when they are navigation controllers and only when the "More" navigation hierarchy is in use.
The console message (regarding two-stage rotation animation) suggests that something within the framework (the More Navigation Controller?) is still using a two-stage animation, even though single stage is now recommended as of iPhone OS 3.0.
That could explain why willAnimateRotationToInterfaceOrientation: is not called in that particular case. Per Apple's view controler documentation, this message will NOT be invoked when two-stage, first/second-half orientation messages are being responded to instead.
A slightly modified version of Victorb's answer which allows every single view controller to decide if it allows rotation.
Here as a gist for easier copying & forking
AppDelegate.h
#interface UITabBarController (MyApp)
#end
#interface UINavigationController (MyApp)
#end
AppDelegate.m
#implementation UITabBarController (MyApp)
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
UIViewController *selectedVC = [self selectedViewController];
if ([selectedVC respondsToSelector:#selector(shouldAutorotateToInterfaceOrientation:)]) {
return [selectedVC shouldAutorotateToInterfaceOrientation:toInterfaceOrientation];
}
//optimistic return - if you want no rotation, you have to specifically tell me!
return YES;
}
#end
#implementation UINavigationController (MyApp)
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
UIViewController *visibleVC = [self visibleViewController];
if ([visibleVC respondsToSelector:#selector(shouldAutorotateToInterfaceOrientation:)]) {
return [visibleVC shouldAutorotateToInterfaceOrientation:toInterfaceOrientation];
}
//optimistic return - if you want no rotation, you have to specifically tell me!
return YES;
}
#end
Related
Hi I've seen this question asked a few times already but with no definite answer yet so I created it for xcode 7 and swift2 (which may have changed things a bit anyway).
I created a project using Xcode 7 and Cocoa OSX Story boards + swift2, so my project started with a NSWindowController that Connects to a NSViewController (as expected!). I added a NSToolbar to my window controller and added a NSButton to the toolbar. I changed my NSViewController to be one of the new NSSplitViewController that links to three NSViewControllers and displays their views horizontally - with vertical dividers - (similar to the layout you see in the photo app or pages in Yosemite +). My final goal will be that the button in My toolbar shows and hides the first split.
It is my understanding is, and I would expect that to achieve this I should create an action in the NSSplitViewController that changes the auto layout constrains more or less in the way they are working it out here: How to do collapse and expand view in mac application?.
And then somehow link this action to the NSButton that is in the Toolbar... which happens to be in the NSWindowController (far up and isolated in the hierarchy)...
I have already gone through other questions about NSToolbar and storyboards and failed to accomplish my goal:
The YouTube video: Cocoa Programming L17 - NSToolbar which is the closest I found to solve the problem, but his method does not work for storyboards, only creating your own xib file.
In this question: How to use NSToolBar in Xcode 6 and Storyboard? One person proposes to make the link using the first reponder and expecting everything to hook up at run-time (which looks a bit dodgy and not the way apple would implement it I think...). A second person suggested to create a view controller variable in the NSWindowController and manipulate its properties from there... but again, a bit dodgy too.
One latest comment I saw in that question which seems the best way to tackle the problem (but still not as good as I guess it could be) is to add a NSObjectController to the dock of each scene and when the scene loads, set the values of the objects to the other secene's controller. Is this really the best way to go ahead? If so, how could I achieve this one?
Apple did mention (again) in WWDC15 that they created storyboards for osx and the split-view controller that owns view-controllers so that you can move your logic and work to the specific view-controller, so I would be expecting to do everything from inside my split-view controller as this is the target that needs to change.
Does anyone know how to achieve this from the view controller itself? I really haven't been able to find a way to connect my ToolBarItem to it.
OK, I've created this question quite a few days ago and no answer so far so I've answer with what I recently did to overcome the problem.
After I created my Xcode project I did this:
Created a subclass MySplitViewController for the NSSplitViewController
Added an IBOutlet for each NSSplitViewItem. For example:
#IBOutlet weak var mySplitViewItem: NSSplitViewItem!
Created a subclass WindowController for the NSWindowController
Added an IBAction in the WindowController class that links to the NSToolbarItem (my button)
Added a property that gets the Window Controller's content as MySplitViewController
var mySplitViewController: MySplitViewController {
return self.window?.contentViewController as! MySplitViewController
}
Now I can access the split view controller's property from the Window Controller in the action I created:
mySplitViewController. mySplitViewItem.collapsed = true
I created some sample code that does this (but using a view controller and changing the text for a label here, just in case someone wants to see a working project with this behaviour. And a blog post about it too :)
One person proposes to make the link using the first reponder and expecting everything to hook up at run-time (which looks a bit dodgy and not the way apple would implement it I think...).
I think this first responder method is actually the proper way.
As an example:
Add something similar to the following, in whichever view controller makes sense.
#IBAction func doSomething(_ sender: AnyObject?) {
print("Do something.")
}
This will magically show up in the first responder:
In your storyboard, right-click the orange "first responder" icon above your window controller, and you should see doSomething in the very long list. You just need to connect that up to your toolbar button.
In the following screen capture, you can see my "Toggle Sidebar" button is connected to the toggleSidebar action in my first responder.
I didn't even have to write this method — it's provided by NSSplitViewController:
#IBAction open func toggleSidebar(_ sender: Any?)
So, I was working this same issue and finding no solution as you experienced. I read your post and was trying to figure how I would implement your solution when it occurred to me to use a notification. In about 30 seconds, I had a perfectly fine working solution:
In your windowController add an IBAction to post a notification like so
-(IBAction)toggleMasterViewClicked:(id)sender
{
[[NSNotificationCenter defaultCenter] postNotificationName:#"TestNotification" object:nil];
}
Hook up that action to your NSToolbarItem, then in the viewController add self as an observer for that notification like so
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(toggleMasterView:) name:#"TestNotification" object:nil];
In your case, selector would be updateMyLabelText
I don't really see any downside here. No reference to other objects needed, no dependancies. Works flawlessly for me
While connectiong IBActions works by using either the First Responder or by adding an "Object" to the scene, then changing its class to the window's view controller class, this doesn't help with IBOutlets and delegates that you'd like to point to the view controller.
Here's a work-around for that:
Add the Toolbar to the View Controller, not to its Window. That way, you can make all the IBOutlet connections in the View Controller Scene easily. I've done that for years and found no issues with it, even when using Tabs.
You'll have to assign the window's toolbar in code, then. E.g. like this:
#interface ViewController ()
#property (weak) IBOutlet NSToolbar *toolbar; // connect this in your storyboard to the Toolbar that you moved to the View Controller Scene
#end
- (void)viewWillAppear {
[super viewWillAppear];
self.view.window.toolbar = self.toolbar;
}
I am several levels deep in a storyboard and want to unroll everything all the way back to the first screen. Fortunately, there are APIs designed to do exactly this:
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
[topController dismissViewControllerAnimated:NO completion:nil];
However, this method seems to "unroll" the view stack one by one, causing each view between my current position and the first screen to briefly invoke viewWillAppear, viewDidAppear, viewWillDisappear, and viewDidDisappear. This causes a cacophony of activity in my app, as most of the intermediate screens do interesting things when they appear. I can set breakpoints in Xcode and watch these methods get invoked in reverse order back to the main screen.
I need a way to pop back to the start of the storyboard without causing every screen along the path to light up and do work.
If this means I cannot use viewWillAppear for this purpose any more, I am willing to switch to a replacement method as long as one exists.
This is expected behaviour. I assume you're presenting the layers of views with presentViewController... calls on each previous view.
You should look at using a UINavigationController as your top level view instead. Then you can just call popToRootViewControllerAnimated: when you want to go all the way back.
With iOS8, I noticed that a view controller was no longer receiving a UIKeyboardWillSHowNotification, when it previously was with iOS7.
Here's the scenario:
1.) View Controller A is displaying a keyboard, and pushes View Controller B without resigning first responder
2.) View Controller B has a control that becomes first responder during its viewDidLoad call, while it's being created by VCA, before it's pushed onto the nav controller
3.) If VC A is NOT displaying a keyboard when pushing B, the notifications work fine. However, if A is still editing when pushing B, then B does not get a keyboard will show notification.
Without the keyboard notification, VC B is not resizing / repositioning and does not look right.
The workaround I'm using until I find a solution is to do the following from any view controllers that might be editing when pushing another view controller that might be editing:
i.e., before pushing another view controller, be sure to call:
[self.view endEditing:YES];
While it works, it doesn't seem good that the view controller (B) can be 'broken' by the state of the app prior to displaying it.
Question: Am I doing something wrong here?
As far as I can tell, one of 3 things are possible:
A.) I should be getting the notifications, but I'm not b/c I'm doing something wrong
B.) I should be getting the notifications, but I'm not b/c of a bug
C.) I can't rely on always getting the notifications...But if I don't get the notifications in VC B when it appears, I need to be able to get the keyboard dimensions of the displayed keyboard without relying on the keyboard notification info. All the apple docs say to use the notifications though (as far as I can find).... which points back to options A.) or B.).
I can create and upload sample code later tonight / early tomorrow to try and isolate / for you all to test/reproduce to see what I'm doing.
I can see the same issue with iOS8 / xCode6 (works with iOS7 and xCode5). In my case, I'm observing a systemStatus property on the model in my AppDelegate so as to log the user out and bring the user back to the login screen when the user logs out from anywhere in the app. I'm doing that by setting the window.rootViewController to the loginViewController in my App Delegate observeValueForKeyPath: method.
This works fine on iOS7 / xCode5 but on iOS8 / xCode6, I loose the keyboard in the way. Looks like my loginViewController might be registering for keyboard notifications (in its ViewWillAppear method) before the window's rootViewController switch is complete (in iOS8) thus registering to the old window's notification center...
I moved the registration for keyboard notifications to the ViewDidAppear: method instead and that seems to fix it but somehow this seems to be called twice for some reason.
Required:
I want to enable iOS7 swipe to back feature with custom navigation back button item.
Current Implementation:
After researching a lot, I found the following solution to be best:
Set the delegate of the gesture recognizer as follows
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;
This, creates a lot of bugs as mentioned in this stackoverflow answer. To avoid that, subclassing the UINavigationController seems to be the only feasible option. I did that as mentioned in this blog by Keighl.
Problem:
Basic swipe to back feature is working, but the strange thing is that, sometimes, the same viewController that is being dismissed, appears again after the pop action is completed.
i.e. suppose the navigation stack looks like A -> B. Popping B will again bring up B. This keeps on happening until eventually the viewController B actually gets dismissed and A appears.
This happens to all views in all viewController objects and not just to a specific one.
Also, I have ensured that the push method is called only once at all places.
I also tried logging the navigation stack at each point, but there is only one instance of each viewController.
Point to note:
I need to disable the swipe feature in certain views. I did this by writing the code to disable and enable the swipe gesture in viewDidAppear and viewDidDisappear respectively.
Please provide your valuable suggestions or a solution to this problem. Thanks!
Short answer: You should add a UIScreenEdgePanGestureRecognizer to your view controller if you want to add a pop gesture where none exists. Modifying the existing interactivePopGestureRecognizer is probably not the right approach. Do this:
[self addGestureRecognizer:({
UIScreenEdgePanGestureRecognizer *gesture =
[[UIScreenEdgePanGestureRecognizer alloc]
initWithTarget:self action:#selector(pop)];
gesture;
})];
and
-(void)pop {
// pop your view controller here
}
Long answer: Forcing the interactivePopGestureRecognizer.delegate is what breaks your code.
If you need to cast self as such:
self.navigationController.interactivePopGestureRecognizer.delegate =
(id<UIGestureRecognizerDelegate>)self;
...it is because self is not a UIGestureRecognizerDelegate. The following should compile, link, build and run or you are setting yourself up for trouble:
self.navigationController.interactivePopGestureRecognizer.delegate = self;
Note that being a UIGestureRecognizerDelegate specifically allows you to tweak a gesture's behavior at runtime, assuming you are implementing one of the following and ensuring that the tweak applies to a gesture you own:
gestureRecognizerShouldBegin:
gestureRecognizer:shouldReceiveTouch:
gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:
gestureRecognizer:shouldRequireFailureOfGestureRecognizer:
gestureRecognizer:shouldBeRequiredToFailByGestureRecognizer:
By constantly changing the delegate of that interactivePopGestureRecognizer you did not create, all you are doing is preventing the iOS behavior to take place.
From the documentation
UINavigationController -interactivePopGestureRecognizer
The gesture recognizer responsible for popping the top view controller off the navigation stack. (read-only)
In plain English: Use this value is you need to combine that gesture with your own gesture. But you are not supposed to modify its behavior:
...You can use this property to retrieve the gesture recognizer and tie it to the behavior of other gesture recognizers in your user interface...
my app has tabBarController with 3 views and in one of them I want to popup a web browser with the ability to return back to the application. To do that I am using UINavigationController.
In myAppDelegate.h I have defined the property UINavigationController *nav and in myAppDelegate.m I have #synthesize nav.
In the class where the webPopup function resides upon pressing the button my code comes to this function.
- (IBAction)showWeb:(id)sender {
myAppDelegate *app=[[UINavigationController alloc] initWIthRootViewController:self];
// because I want to return back to the same view
webController *web = [[webController alloc] initWithStyle:UITableViewStypeGrouped];
[app.nav pushViewController:web animated:YES];
app.nav.view.frame = CGRect(,0,320,430);
[self.view.window addSUbview:app.nav.view];
}
The web popup occurs but it is moved vertically, when I press "back button" my former view appears as well and it is also shifted vertically from what it was before.
After going back and forth few times the thing hangs.
Questions:
1. what can cause the shift?
2. how to avoid when I go "back" to see the title(test from the "back"button, I think this might cause a shift when I go back.
3. how to find out why it hangs after few attempt?
Thanks.
Victor
The line:
myAppDelegate *app=[[UINavigationController alloc] initWIthRootViewController:self];
makes no sense to me. Surely your compiler is warning you about that? What is "myAppDelegate" defined as? Classes should have a capital letter at the front, by the way.
Also, the line
[self.view.window addSUbview:app.nav.view];
is highly suspect, because the UIWindow for your application should have only one child UIView. You shouldn't just add more views willy nilly and expect things to work. It is possible to change the child UIView by removing the old one and adding a new one, but you don't seem to be doing that. Having more than one child UIView of UIWindow gets you into trouble very quickly -- for example, device orientation changing can break.
I'm not exactly clear as to why the app delegate (or the window for that matter) needs to be messed with at all to do what you are trying to do. Sounds like you should just be using standard Nav View Controllers and Web Views.
Also, you are alloc init'ing w/o any memory management.