WLINewPostViewController *newPostViewController = [[WLINewPostViewController alloc] initWithNibName:#"WLINewPostViewController" bundle:nil];
UINavigationController *newPostNavigationController = [[UINavigationController alloc] initWithRootViewController:newPostViewController];
newPostNavigationController.navigationBar.translucent = NO;
[tabBarController presentViewController:newPostNavigationController animated:YES completion:nil];
So I just simply push a new UIViewController.
Then after it posts the server callback calls a method with this code from the WLINewPostViewController.m:
[self dismissViewControllerAnimated:YES completion:^{
NSLog(#"Completed");
}];
[[self navigationController] popViewControllerAnimated:YES];
if (self == self.navigationController.visibleViewController){
NSLog(#"self = visibile");
}
if (self == self.presentingViewController.presentingViewController){
NSLog(#"self = presenting");
}
}
I tried a bunch of different things and none work.
I am relatively new to Xcode but after trying
[self dismissViewControllerAnimated:YES completion]
[self.navigationController popViewControllerAnimated:YES]
[self.navigationController.visibleViewController.presentedViewController dismissViewControllerAnimated:YES completion:nil];
[self.navigationController dismissViewControllerAnimated:YES completion:nil];
and every other possibility, I am officially stumped. The WLINewPostViewController still won't dismiss.
It Logs out "self = visible"
Let me illustrate what you are trying to do
You have a navigation controller with Controller A.
Here you are trying to present another Controller B from Controller A.
Now when you get a callback from the server, you should call dismissViewControllerAnimated from Controller B to dismiss itself.
So after dismissViewControllerAnimated:completion: method call, the Controller B will be dismissed and Controller A will be shown automatically. Now you do not need to call popViewControllerAnimated: in completion block again as there is no other Controller in navigation controller to load.
If you have different use case, let me know I can provide solution.
You are presenting a view over navigationbar instead of pushing it over navigationbar.
When push you pop. When you present you dismiss. So instead of popViewControllerAnimated you need to use dismissViewControllerAnimated:completion
dismiss behaves differently depending on the receiver. From the docs:
The presenting view controller is responsible for dismissing the view controller it presented. If you call this method on the presented view controller itself, it automatically forwards the message to the presenting view controller.
If you present several view controllers in succession, thus building a stack of presented view controllers, calling this method on a view controller lower in the stack dismisses its immediate child view controller and all view controllers above that child on the stack. When this happens, only the top-most view is dismissed in an animated fashion; any intermediate view controllers are simply removed from the stack. The top-most view is dismissed using its modal transition style, which may differ from the styles used by other view controllers lower in the stack.
In short, if the vc on top calls it on itself, it dismisses itself. Anywhere else on the stack dismisses to that point, animating only the topmost vc.
What's extra confusing (for you and many others) is that the navigation vc has a stack too, and your problem is complicated further by presenting an navigation vc atop a tab-bar vc.
So what to do? The question is unclear about which vc is the receiver in the posted code (who is self in that snippet?). The text implies that self is a vc on the stack of the presented navigation vc, like...
TabBarVC --- presents ---> NavVC
| |
| --- viewControllers stack = rootVC, vc1
|
---> viewControllers for each tab
... and it's root or vc1 that wants to dismiss. If I'm right about that, then, given the docs, the solution is clear:
[self.navigationController dismissViewControllerAnimated:YES completion:^{}];
will put us back on the tabbar vc on whatever tab was visible when we did the present.
Related
I have a firstViewController that I display with
[self.navigationController pushViewController:firstViewController animated:true];
Then when a button in this first VC is clicked, I present a second one:
[self presentViewController:secondViewController animated:true completion:nil];
And from this second one I present the third VC as a modal:
[thirdVC modalPresentationStyle];
[thirdVC setModalPresentationStyle:UIModalPresentationOverCurrentContext];
[self presentViewController:thirdVC animated:true completion:nil];
The problem is that I want to display the firstVC when the validate button of the last VC is clicked. So I have to dismiss the third and the second one. I tried this in the validateAction (in the third VC):
[[self parentViewController] dismissViewControllerAnimated:true completion:nil];
[self dismissViewControllerAnimated:true completion:nil];
But the result is that the thirdVC (the modal one) is dismissed, and from the debugger I can see that the firstVC is covered by the secondVC.
How can I dismiss the second and the third VC at the same time in order to return to the first one?
NOTE: I want to push the firstVC after the dismiss of the others because I have to reload the data (in the fristVC viewDidLoad)
From Apple's Documentation:
The presenting view controller is responsible for dismissing the view controller it presented. If you call this method on the presented view controller itself, UIKit asks the presenting view controller to handle the dismissal.
In other words, the third viewController asks the second viewController to dismiss its presented viewController, which is the third one. Then the third viewController tries to dismiss itself, causing UIKit to ask the second viewController to dismiss the third one once more.
You will have to go one layer up and ask the first viewController to dismiss its presented view controller.
It is good practice that the third viewController does not know anything about the presentation hierarchy. You can use delegation to tell the first viewController that the task is finished. An exit segue is a very nice alternative if you use storyboards.
You only have to call -dismissViewControllerAnimated:completion: once if you address the first viewController:
If you present several view controllers in succession, thus building a stack of presented view controllers, calling this method on a view controller lower in the stack dismisses its immediate child view controller and all view controllers above that child on the stack.
I am having a strange problem that I can't seem to find the cause for.
When attempting to present a modal view controller on a navigation controller the navigation controller is popping all of my view controllers underneath when the modal is dismissed.
So after pushing a few view controllers and presenting a modal on the topViewController, I end up back at the rootViewController when the modal is dismissed.
Anyone had this happen to them lately, I can't seem to find the reasoning for why this is happening?
This answer is for #rshev:
It was actually a user error. Here's what was happening: I had a view controller with a manually added navigationController on top of it (as a subview/child VC). The nav controller then had 3 VCs in its stack. The third (and visible) VC was presenting an image picker controller. When the image picker was dismissed, I momentarily saw my third VC , then it quickly popped back to the 1st, discarding the other two VC's from memory.
So what went wrong? What I didn't realize is that viewDidAppear (and viewWillAppear) was being called on my content view controller (the one with nav controller for its subview). This content VC was actually setting its navigation controller (and adding it as a subview) on viewDidAppear, thus covering up the original nav controller.
To solve it, I just added a static boolean to determine when the first VC FIRST appears, like so:
- (void) viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
static BOOL firstAppearance = YES;
if (firstAppearance)
{
firstAppearance = NO;
UINavigationController *navController = [self.storyboard instantiateViewControllerWithIdentifier:#"NavigationController"];
[navController.view setFrame:self.view.bounds];
[self.view addSubview:navController.view];
[self addChildViewController:navController];
[navController didMoveToParentViewController:self];
}
}
Hope that helps.
I'm building a complex app that has kind of a branch in the middle.
At some point in the app, a particular UIViewController is presented, we'll call it mainViewController (shortened mainVC).
The mainVC presents another view controller, by code, using the following code (I strip out parts of it for privacy reasons):
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"SecondaryStoryboard" bundle:secondaryBundle];
SecondViewController *secondVC = [storyboard instantiateInitialViewController];
[self presentViewController:secondVC animated:YES completion:nil];
So the secondVC will later present another view controller, called thirdVC. This is done using a custom segue, set in the storyboard used in the code above, which code looks like this:
#implementation VCCustomPushSegue
- (void)perform {
UIView *sourceView = ((UIViewController *)self.sourceViewController).view;
UIView *destinationView = ((UIViewController *)self.destinationViewController).view;
UIWindow *window = [[[UIApplication sharedApplication] delegate] window];
destinationView.center = CGPointMake(sourceView.center.x + sourceView.frame.size.width, destinationView.center.y);
[window insertSubview:destinationView aboveSubview:sourceView];
[UIView animateWithDuration:0.4
animations:^{
destinationView.center = CGPointMake(sourceView.center.x, destinationView.center.y);
sourceView.center = CGPointMake(0 - sourceView.center.x, destinationView.center.y);
}
completion:^(BOOL finished){
[self.sourceViewController presentViewController:self.destinationViewController animated:NO completion:nil];
}];
}
#end
As you can see this segue presents the destination view controller modally (by the use of presentViewController:) with a custom animation (a slide from right to left).
So basically up to here everything is fine. I present the secondVC with a classic modal animation (slide up from bottom) and present the thirdVC with my custom transition.
But when I want to dismiss the thirdVC, what I want is to go back directly to the mainVC. So I call the following from the thirdVC :
self.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self.presentingViewController.presentingViewController dismissViewControllerAnimated:_animate completion:nil];
That way, I'm calling dismissViewControllerAnimated: directly on mainVC (referenced by self.presentingViewController.presentingViewController), and I'm expecting the thirdVC to be dismissed with an animation, and the secondVC to just disappear without animation.
As Apple says in the UIViewController Class Documentation:
The presenting view controller is responsible for dismissing the view
controller it presented. If you call this method on the presented view
controller itself, it automatically forwards the message to the
presenting view controller.
If you present several view controllers in succession, thus building a
stack of presented view controllers, calling this method on a view
controller lower in the stack dismisses its immediate child view
controller and all view controllers above that child on the stack.
When this happens, only the top-most view is dismissed in an animated
fashion; any intermediate view controllers are simply removed from the
stack. The top-most view is dismissed using its modal transition
style, which may differ from the styles used by other view controllers
lower in the stack.
The issue is that it's not what happens. In my scenario, the thirdVC disappears, and shows the secondVC being dismissed with the classic modal slide to bottom animation.
What am I doing wrong ?
Edit :
So #codeFi's answer is probably working in a classic project, but the problem here is that I'm working on a framework. So mainVC would be in a client app, and the secondVC and thirdVC are in my framework, in a separate storyboard. I don't have access to mainVC in any other way than a reference to it in my code, so unwind segues are unfortunately not an option here.
I've been having this exact same issue, and I've managed to visually work around it by adding a snapshot of the screen as a subview to secondVC.view, like so:
if (self.presentedViewController.presentedViewController) {
[self.presentedViewController.view addSubview:[[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO]];
}
[self dismissViewControllerAnimated:YES completion:nil];
Not pretty, but it seems to be working.
NOTE: if your secondVC has a navigation bar, you will need to hide the navigation bar in between snapshotting the screen and adding the snapshot as a subview to secondVC, as otherwise the snapshot will appear below the navigation bar, thus seemingly displaying a double navigation bar during the dismissal animation. Code:
if (self.presentedViewController.presentedViewController) {
UIView *snapshot = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO];
[self.presentedViewController.navigationController setNavigationBarHidden:YES animated:NO];
[self.presentedViewController.view addSubview:snapshot];
}
[self dismissViewControllerAnimated:YES completion:nil];
I had the same issue and I've fixed it by using UnwindSegues.
Basically, all you have to do is add an IBAction Unwind Segue method in the ViewController that you want to segue to and then connect in IB the Exit action to your Unwind Segue method.
Example:
Let's say you have three ViewControllers (VC1, VC2, VC3) and you want to go from VC3 to VC1.
Step 1
Add a method to VC1 like the following:
- (IBAction)unwindToVC1:(UIStoryboardSegue*)sender
{
}
Step 2
Go in Interface Builder to VC3 and select it. Then CTRL-drag from your VC icon to Exit icon and select the method you've just added in VC1.
Step 3
While still in IB and with VC3 selected, select your Unwind Segue and in the Attributes Inspector add a Segue Identifier.
Step 4
Go to VC3 where you need to perform your segue (or dismiss the VC) and add the following:
[self performSegueWithIdentifier:#"VC1Segue" sender:self];
I have an iOS app that has a connection to a server. If we get disconnected, I want to be able to dismiss the top view controllers to get back to a "connecting to server" view controller. The problem is that a disconnection can occur at any time, including during a transition between view controllers.
The view controller hierarchy is like so:
ConnectingToServerViewController
SignInViewController
MainAppViewController
Other view controllers
When a disconnection is detected I want the view hierarchy to collapse back to:
ConnectingToServerViewController
So when a disconnection is detected, this method is called on the ConnectingToServerViewController to dismiss anything that it has presented and go back to attempting to connect to server:
- (void)restartSession
{
if (self.presentedViewController) {
[self dismissViewControllerAnimated:NO completion:nil];
}
}
However, if I try to dismiss while a view transition is occurring, I get errors such as
*** Assertion failure in -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:], /SourceCache/UIKit/UIKit-2380.17/UIWindowController.m:211
attempt to dismiss modal view controller whose view does not currently appear. self = <YYYYYViewController: 0x2089c8a0> modalViewController = <XXXXXViewController: 0x208e6610>
attempt to dismiss modal view controller whose view does not currently appear. self = <WWWWWWViewController: 0x1fd9e990> modalViewController = <YYYYYViewController: 0x2089c8a0>
The first of which will crash the app, the second will just not dismiss anything and continue to show the current presented view controller.
Thoughts:
delays won't work since we don't know when to start the delay
is there a way to track when view transitions complete?
should all view controllers override willAppear, didAppear and alert the app when it is safe to dismiss?
perhaps instead of dismiss, I should just set a new root view controller?
I've made sure that all overridden view(will|did)(dis)?appear methods call the appropriate super method.
Any solution that requires all view controllers to override view(did|will)appear methods to track state sounds like it could cause issues if we forget to set the base class for a new view controller.
Do something like this. Try this out once,
UIViewController *controller = self.presentingViewController; //THIS LINE IS IMP
[self dismissViewControllerAnimated:YES
completion:^{
[controller presentViewController:adminViewController animated:YES completion:nil];
adminViewController.view.superview.frame = CGRectMake(1024/2 - 400, 768/2 - 280, 800 , 560);//it's important to do this after
[adminViewController release];
}];
One way that has worked for me is to assign a new view controller to the root view controller. That way, views in the old hierarchy can animate and transition to their hearts content while we have new controllers.
eg
- (void)restartSession
{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
ConnectingToServerViewController *vc = [storyboard instantiateViewControllerWithIdentifier:#"ConnectingToServerViewController"];
vc.modalPresentationStyle = UIModalPresentationFullScreen;
[UIApplication sharedApplication].delegate.window.rootViewController = vc;
}
I'm not sure if I'm aware of all the downsides to this though. Perhaps the old view controllers will never get freed because of a dangling strong reference? We're no longer reusing ConnectingToServerViewController, we have to recreate that each time.
I based the code on what I saw in this answer for Managing and dismissing Multiple View Controllers in iOS.
It seems like you are trying to dismiss the view controller when it is not currently on screen. To check if it is on screen you could use:
if (self.presentedViewController.view.window)
{
[self dismissViewControllerAnimated:NO completion:nil];
}
else
{
self.presentedViewController = nil;
}
I will answer in order.
is there a way to track when view transitions complete?
You could try with the UINavigationControllerDelegate (if you are using one of those). Other approach could be using a custom animator.
should all view controllers override willAppear, didAppear and alert the app when it is safe to dismiss?
That's an option. You are free to do it if you want. Another option is not to do that. I think that container view controllers such as navigation controller has better approaches.
I should just set a new root view controller?
I would suggest to do the opposite. I would set the SignInViewController / MainAppViewController as the root flow, and present modally ConnectingToServerViewController on demand. In my opinion that's a healthier approach.
Hope it helps.
I want to know what is the different of them.
when I can call
[self dismissViewControllerAnimated:YES completion:nil];
and when I should call
[self.navigationController popViewControllerAnimated:YES];
according document of apple:
dismissViewControllerAnimated means
"Dismisses the view controller that was presented by the receiver."
But I always fail to dismiss view controller by this method.
-dismissViewControllerAnimated:completion:
Used to dismiss an UIViewController, which was presented by the method:
-presentViewController:animated:completion:.
-popViewControllerAnimated:
Method of UINavigationController is used to pop a controller shown by
-pushViewController:animated method of UINavigationController.
In the first case the view controller's view shows as a modal controller (usually from bottom to top), and the second case you are pushing a view controller in the navigation stack of UINavigationController.
your selected application is navigation based application means
[self.navigationController popViewControllerAnimated:YES];
your selected application is other than the navigation based application means
[self dismissViewControllerAnimated:YES completion:nil];