Interface Builder IB - Navigation Controller, skipping a view - ios

Hello I am new to iOS and have a question about navigating through my views.
I am using IB wiring up the PREVIOUS and NEXT buttons in the nav bar that pushes my views. This all works fine. However I am having trouble finding out where exactly what I need to do or where I need to place the code so I can skip over a view. To simplify my situation...
-I have 1 Nav Controller and 4 View Controllers named VC1, VC2, VC3, VC4. Each VC has a .H/.M
-Starting from VC1, they follow one after the other.
Say I want to skip VC3 and jump right to VC4 based on a setting in VC2. Where would I put the code to do this? Would I need to unhook the IBAction method from the NAV buttons at VC3?
I do apologize if this has been covered before. If there is a tut or if you know of a post that answers this, please let me know. I did do a search but the search was returning generic posts probably due to me using the wrong terminology.
Thanks in advance.

A couple of thoughts:
If you want to push from VC2 to either VC3 or to VC4, rather than having VC3 immediately push to VC4 in special cases, I think it's better to just have VC2 push directly to the appropriate view controller. Thus you might have an IBAction in VC2 that would do this for you:
- (IBAction)pushToNext:(id)sender
{
BOOL skipToVC4 = ... // put in whatever logic you'd use to bypass VC3 and go directly to VC4
UIViewController *nextController;
if (skipToVC4)
{
nextController = [self.storyboard instantiateViewControllerWithIdentifier:#"VC4"];
// obviously, if using NIBs, you'd do something like:
// nextController = [[ViewController4 alloc] initWithNibName:#"VC4" bundle:nil];
}
else
{
nextController = [self.storyboard instantiateViewControllerWithIdentifier:#"VC3"];
}
[self.navigationController pushViewController:nextController animated:YES];
}
This way, when you pop back from VC4, you'll pop back directly to the appropriate view controller (e.g. if you pushed from VC2 to VC4, when you pop, you'll pop right back to VC2 automatically.
And, obviously, if you're using storyboards, rather than manually invoking pushViewController, you could have two segues from VC2 (one to VC3 and one to VC4), give them appropriate identifiers, and then just invoke performSegueWithIdentifier to segue to the appropriate view controller. But the idea is the same: You can define an IBAction that performs the appropriate segue depending upon whatever logic you so choose.
You say that you have "PREVIOUS and NEXT buttons in the nav bar that pushes my views", I wonder about your "PREVIOUS" button. Is that doing a popViewControllerAnimated? Generally, a "NEXT" button will push to a new view controller, but the "PREVIOUS" button should not push to the previous view, but pop back to it. If you don't pop back, you can end up with multiple instances of some of your prior view controllers. Thus, the "PREVIOUS" button should be linked to an IBOutlet that does something like:
- (IBAction)popToPrevious:(id)sender
{
[self.navigationController popViewControllerAnimated:YES];
}
When popping back, you'll obviously pop back to the view controller that you pushed from. If you want to skip a few of the view controllers as you're popping back in iOS versions prior to 6.0, you would use popToViewController or popToRootViewControllerAnimated. For example, let's say that you pushed from VC1 to VC2, to VC3, to VC4. If you want to pop back from VC4 all the way to VC1, you would hook up and IBAction in VC4 like:
- (IBAction)popToRoot:(id)sender
{
[self.navigationController popToRootViewControllerAnimated:YES];
}
Or, if you wanted to pop back from VC4 to VC2, you would
- (IBAction)popToVC2:(id)sender
{
for (UIViewController *controller in self.navigationController.viewControllers)
{
if ([controller isKindOfClass:[ViewController2 class]])
{
[self.navigationController popToViewController:controller animated:YES];
return;
}
}
}
You can avoid this iteration through the navigationController.viewControllers if you passed a reference of VC2 to VC3 and then again to VC4, but sometimes the above technique is easier.
By the way, if you're supporting iOS 6 and above, only, and are using storyboards, you can also use unwind segues, which are a more elegant way of popping back to a particular view controller. But it's not clear whether (a) you're using storyboards; and (b) you're supporting iOS 6 and above only, so I'll refrain from a discussion of unwind segues at this point.

First:
Show us some code, where you are pushing new view controllers, maybe your whole navigation controller code
Second (Solution):
I assume:
Your prev/next buttons are linked to your navigationController class
you have the appropriate methods (prevPressed:/nextPressed:), which are called, when you click one of the buttons
I can help you with the following:
you know which controller is visible at the moment with the visibleViewController #property
each time you click on a button in the navBar you can ask the visibleViewController which next/previous view controller should be pushed/popped
Best solution would be, if all of your controllers VC1/2/3/4 are a subclass of a viewController class, which defines a method in it's interface:
- (Class)nextViewControllerClass;
- (Class)previousViewControllerClass;
and in the implementation:
- (Class)nextViewControllerClass {
return [VC4 class];
}
- (Class)previousViewControllerClass {
return [VC1 class];
}
And in your navigationController code the do this:
- (IBAction)next:(id)sender {
UIViewController *nextViewController = [[[self.visibleViewController nextViewControllerClass] alloc] init];
[self pushViewController:nextViewController animated:YES];
}

Related

How do i handle navigation Back button view hierarchy?

Here is the problem
1) Rootview controller - MYAssetVC-> Embedded with NavigationController here pushing for button to another Addfilevc.
2) Addfilevc Has dropdownTextfield It will push to another vc have tableview selected row will display in the textfield.
3)if i select another value from the dropdown textfield it will push to the vc again there i will select.
Navigation bar back button will navigate to all my view hierarchy i want to handle this one. if i go to same view it should navigate back only once that to the recent visit how to do this.
As i am new to iOS. give any suggestion.
Navigation from 1->2->3
navigation backbtn 3->2->1
if i navigate like this 1->2->3-> backbutton 3->2 again 2->3 backbutton 3->2 again 2->3
IF i navigate now using back it is displaying all my route path it should navigate like 1->2->3> and 3->2->1 if any number of times i perform actions in 2 & 3.
1,2,3 are view controllers.
Create an IBAction for the back button and use popViewController.
[self.navigationController popViewControllerAnimated:YES];
This will help you to go back one page. You have to write this in all the pages where there is a back button and you want to go back one page.
If you want to go back directly to rootViewController, try this:
[self.navigationController popToRootViewControllerAnimated:YES];
And if you want to pop to any specific viewController in the stack, you run a for loop to find the viewController you want to navigate to and then simply popToViewController, like this:
for (UIViewController *viewController in self.navigationController.viewControllers) {
if ([viewController isKindOfClass:[Addfilevc class]]) {
[self.navigationController popToViewController:viewController animated:YES];
}
}
Hope this helps to clear your concept.
EDIT
In swift:
The [self.navigationController popViewControllerAnimated:YES]; will become self.navigationController?.popViewControllerAnimated(true)
The [self.navigationController popToRootViewControllerAnimated:YES]; will become navigationController?.popToRootViewControllerAnimated(true)
And the for loop will be as below:
You can use this if you are using storyboard
let switchViewController = self.storyboard?.instantiateViewControllerWithIdentifier("view2") as ComposeViewController
self.navigationController?.pushViewController(switchViewController, animated: true)
And the for-in loop
if let viewControllers = self.navigationController?.viewControllers {
for viewController in viewControllers {
self.navigationController!.popToViewController(viewController, animated: true);
}
}
Thanks.

Dismiss a previous Viewcontroller

I am current developing an game with multiple viewcontroller.
VC1(intro) -> VC2(game selection) ->VC3,VC4,VC5(games) -> VC6(display marks)
all the arrows are modal segue
I use unwind segue to go back from VC6 to VC2 and would like to replay. However, when select a game to go to VC3, the VC3 is not brand new as expected. It appears as the finished game condition.
If I really want to replay it after showing the marks, how can I achieve this with segue and Viewcontroller?
Moreover, how can I completely remove the instance of a previous viewcontroller?
You can go back on the parentViewController chain:
UIViewController *viewController = nil;
do {
viewController = self.parentViewController;
} while (![self isViewControllerImLookingFor:viewController]);
Or you could implement a custom navigation stack manager, and store an array of navigation controllers, similar to how UINavigationController does.
You can manipulate the view controller array of your navigation controller like so
NSMutableArray *navigarray = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
[navigarray removeLastObject]; //navigarray contains all vcs
[[self navigationController] setViewControllers:navigarray animated:YES];

Dismissing a ViewController lower in the stack does not behave as expected

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];

How can I present a 'standalone' View Controller ('forgetting' the previous one)

I have a regular UINavigationController with a couple of views attached, which are working perfectly fine. Its RootViewController has a custom Menu-button on the top left, at the same place as the "Back"-button is on the attached views. When clicking this menu-button, the menu appears and presents five options.
Obviously, by clicking one of these option, you would be presented with the ViewController for that option.
I want to completely 'forget' the current ViewController, and move on to this new controller. Usually, I would do something like [self presentViewController....]; or [self.navigationController push..];, but in these methods the current ViewController will, I think, always exists 'below' the new presenting viewController (as you would return to this instantiation if using [self dismissViewController..];, I don't want this).
In the presenting ViewController there will be a menu-option to return back to the original controller, but I still want this to be a clean instantiation of it, and not just popping. By thinking ahead in time, I figured I would potentially create an infinite number of ViewControllers on top of each other by using the methods I know of this way.
I entered the world of iOS after the era of ARC began, so I have no clue how to release or deallocate such views, which I assume has relevance here.
The second View Controller is also supposed to be a root in a UINavigationController, and I'm not sure if it's best to use the same UINavigationController, or if I should present a new one, and dismiss the old. Essentially, I would like to replace the Navigation Controller's rootViewController from the rootViewController, but I don't see how that would be possible. Or possibly push to ViewController2, and then popping the rootViewController out of the hierarchy, leaving the new ViewController as the root, but then I assume I'd have problems with the navigational back-button(if it's even possible).
I figured it's just as easy to let ViewController2 be root at its own NavigationController, and presenting this NavigationController from ViewController1. The problem is, I want to completely remove everything that has to do with ViewController1 and its NavigationController from memory after presenting ViewController2, but I have no idea how.
I'm open to other solutions to my situation, but I'd also like an answer to how I can completely 'forget' a view after presenting another on general basis.
If you want to "forget" controllers, you can just replace the window's root view controller with a new one. The original one will be deallocated if you don't have any other strong pointers to it. I'm not sure I understand all of what you're trying to do, but for example, if you want controller 1 and controller 2 to both be root view controllers of a navigation controller, and you don't want controller 1 around when you switch to 2, then do something like this from controller one:
SecondViewController *second = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:second];
self.view.window.rootViewController = nav;
This will switch out the controllers, and controller 1 and its navigation controller will be deallocated (assuming that the only thing with a strong pointer to the navigation controller was the window, through its rootViewController property).
Create a menu UIViewController and add it as a root to the UINavigationController on launch. Add 1st UIViewController as a child controller to menu UIViewController when viewDidLoad of menu controller is called. When you click menu to show 2nd UIViewController, remove the 1st UIViewController from menu view controller and add 2nd UIViewController to child of the menu view controller. You can put NSLog in both, 1st and 2nd view controller's dealloc method to check if its released or not. Logic is like this
//inside menuvc class
#interface MenuVC{
UIViewController * currentVC; // current child controller to menuVC
}
-(void)viewDidLoad{
[self addChildController:firstVC]; //to add view controller 1 intially
currentVC = firstVC;
}
-(void)add2ndChildController{
[currentVC removeFromParentViewController];
[self addChildController:secondVC]; //to add view controller 2 when needed
currentVC = secondVC;
}
// dealloc of 1st vc
-(void)dealloc{
NSLog(#"first vc released");
}
I just wrote some sample logic of what I explained before, you have to generalize this logic if you feel its right for you. Hope it helps :)

Something like prepareForSegue but for when going back

In my iOS app, I'm using a UINavigationController with segues setup in Xcode. For one of the views, I want to hide the navigation bar, and for the others, I want it to show up. I am able to successfully hide the bar in the main view, then nicely animate it in when I segue to the next view, but when I go back (using the back button in the navigation bar), the bar just disappears, leaving a black rectangle, then switches back to the previous view. I would like to be able to catch this, with something like the opposite of prepareForSegue, and nicely animate the navigation bar out. Is there some way to do this?
There currently is no prepareForDesegue:sender: alternative to prepareForSegue:sender:. The recommended practice is to establish a reference, in the destination ViewController, back to the source ViewController. Then, when the destination ViewController is dismissed, it can notify the source ViewController that it is about to become the top ViewController again.
Typically, the reference is established in prepareForSegue:sender:.
So, to make this concrete, let's suppose that you have ViewControllerA, and are about to segue to ViewControllerB. In ViewControllerB, you would define a property that references ViewControllerA. (This is often done using protocols, but to make it simple, just assume that ViewControllerB has #property ViewControllerA *delegate;.)
Then, in prepareForSegue:sender:, you would do the following:
ViewControllerB * vcB = (ViewControllerB *)[segue destinationViewController];
vcB.delegate = self;
Later, in ViewControllerB, in whatever code is about to get you back to ViewControllerA, you would use self.delegate to reach back to ViewControllerA, and let it know it's about to be presented, and give it the opportunity to do whatever you need to with the UINavigationBar.
In the view's UIViewController that you want the navigation bar to appear, place the following methods:
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[self.navigationController setNavigationBarHidden:YES animated:animated];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:NO animated:animated];
}
You can add some logic in case you want the bar to stick around for any reason (like certain next views still need the bar).

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