I am following this answer to "release" my previous view controller in a UINavigationController.
It works fine however the popping part is the code I am having difficult in getting to work. Basically my app works like this. It starts on a main menu (View 1) then it pushes to View 2 and I use the custom push segue to get to View 3. Now I want to use a different custom segue for popping now to go from View 3 to View 2. However, by using the code below, it pops to View 1 very quickly and then eventually pushes to View 2. It looks like the view controller transition is unnatural and I am just looking to achieve the usual pop transition just instead by using a custom segue to "release" the source view controller.
This is my code I am using now to no avail:
- (void)perform {
// Grab Variables for readability
UIViewController *sourceViewController = (UIViewController*)[self sourceViewController];
UIViewController *destinationController = (UIViewController*)[self destinationViewController];
UINavigationController *navigationController = sourceViewController.navigationController;
// Get a changeable copy of the stack
NSMutableArray *controllerStack = [NSMutableArray arrayWithArray:navigationController.viewControllers];
// Replace the source controller with the destination controller, wherever the source may be
[controllerStack addObject:destinationController];
// Assign the updated stack with animation
[navigationController setViewControllers:controllerStack animated:YES];
}
Is there something I am doing wrong here?
What you want is an "unwind" segue. More about those here: https://spin.atomicobject.com/2014/10/25/ios-unwind-segues/
If you just want to pop View 3 to go back to View 2, can't you just do something like this?
- (void)perform {
UIViewController *sourceViewController = (UIViewController*)[self sourceViewController];
UINavigationController *navigationController = sourceViewController.navigationController;
[navigationController popViewControllerAnimated:YES];
}
I am not sure if this answer is localized to me but after logging my navigation stack hierarchy and playing around with the array, I did this and it works well for me.
- (void)perform {
// Grab Variables for readability
UIViewController *sourceViewController = (UIViewController*)[self sourceViewController];
UIViewController *destinationController = (UIViewController*)[self destinationViewController];
UINavigationController *navigationController = sourceViewController.navigationController;
// Get a changeable copy of the stack
NSMutableArray *controllerStack = [NSMutableArray arrayWithArray:navigationController.viewControllers];
[controllerStack replaceObjectAtIndex:1 withObject:destinationController];
[controllerStack addObject:sourceViewController];
[navigationController setViewControllers:controllerStack animated:NO];
[navigationController popViewControllerAnimated:YES];
}
A more widespread answer would probably be to find the index of the source view controller object in the array and add your destination view controller to the index before it, shifting everything from that prior index on forward one place, that way you don't mess up any of your other view controllers. As I said, the index 1 is what worked for me in this case particularly.
Related
I’m building an iOS app. I want pass array value from one view controller to another through segue.
While doing this i’m getting an error:
[UITabBarController setSports:]: unrecognized selector sent to
instance 0x7b80e2b0.
here is my code:
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:#"sportsSelection"]) {
Play *play=[segue destinationViewController];
play.sports=selectedSports;//error break point is here.
//sports and selected sports are NSMutableArray
}
}
To make the situation a bit clearer, you are getting the error because you are trying to call a method (setSports:) on a class that does not implement this method, this is exactly what the error message tells you:
[UITabBarController setSports:]: unrecognized selector sent to
instance 0x7b80e2b0.
Your segue apparently has a UITabBarController as destination, so it's clear that it does not know about the method setSports:, since this one is actually implemented in your custom view controller (apparently called Play?!).
Then, as Eike pointed out in his answer, you need to get Play from the UITabBarController which it is embedded in. That's why he suggested to use: Play* p = ((UITabBarController*)segue.destinationViewController).viewControllers[0];, it means that you should get the view controller at index 0 from your UITabBarController.
According to your comment, the view controller at index 0 is a UINavigationController, which (naturally) also does not respond to setSports:, because just like UITabBarController it is a class provided by Apple and doesn't know about this method.
Now, you need to find out where in this UITabBarController your custom view controller Play is located. Either it is a direct part of UITabBarController and you can find it by using Eike's approach and just modify the index from 0 to n (where n is the number of view controllers that the UITabBarController has hold of), or another option is that it is embedded in the UINavigationController that you received at index 0, so in that case you'd have to access the UINavigationController's view controller stack (e.g. the array property viewControllers or just the one that is currently on top of the stack using topViewController).
Edit: I want to give you some extra information about what's going on in your code, especially related to Eike's answer:
From the information that you gave us in your question and in the commment to Eike's solution, we can assume the following code to be correct:
if ([[segue identifier] isEqualToString:#"sportsSelection"]) {
UITabBarController *tabBarController = [segue destinationViewController]; // the destination of the segue is your `UITabBarController`
UINavigationController *navigationController = tabBarController.viewControllers[0]; // gets the first of the view controllers contained in your UITabBarController
NSLog(#"view controllers in navigation controller: %#; top view controller: %#", navigationController.viewControllers, navigationController.topViewController); // print all view controllers managed by navigationController
}
EDIT 2: From your comment I can now assume the following code to be correct:
if ([[segue identifier] isEqualToString:#"sportsSelection"]) {
UITabBarController *tabBarController = [segue destinationViewController]; // the destination of the segue is your `UITabBarController`
UINavigationController *navigationController = tabBarController.viewControllers[0]; // gets the first of the view controllers contained in your UITabBarController
Play *controller = (Play *)[[navigationController viewControllers] objectAtIndex:0];
controller.sports=selectedSports;
play.sports = selectedSports;
}
You need to setSports: to your view controller not the UITabBarController.
Play* p = ((UITabBarController*)segue.destinationViewController).viewControllers[0];
p.sports = selectedSports;
In android, switching between activities, is fairly straightforward
you call
Intent intent = new Intent(this,NextActivity.class); <- define the next activity
startActivity(intent); <- start the next activity
finish(); < -get rid of the current activity
now in iOS i know how to do this:
UIViewController *nextviewcontroller = [[UIViewController alloc]initWithNibName:#"nextvc" bundle:nil];
[self presentViewcontroller:nextviewcontroller animated:YES completion:nil];
How do I get rid of the current view controller? so that currentviewcontroller dies after presenting nextviewcontroller ?
[self dismissViewController:YES]; doesnt seem to do the trick
the lifecycle methods viewWillDisappear and viewDidDisappear are called even if I don't call [self dismissViewController:YES];
i want "currentviewcontroller" to be removed from the memory, and from the viewcontroller stack, so that clicking "back" in "nextviewcontroller" will go to some thirdviewcontroller that was before currentviewcontroller
In iOS is different, since there's no concept of Activity and everything is more focused on the app itself (in Android you can mix activities from different apps). Therefore, there's no concept of "view controller stack".
The most similar concept is the "navigation stack" of navigation controllers, where you actually push and pop new view controller into some kind of linear navigation. A navigation bar is automatically created and populated with back buttons.
presentViewController will show your view controller modally upon the current one, but you can't thrash the presenting one since it's holding and containing ("defining context") the new one.
If you use a navigation controller for your navigation hierarchy (I don't know if you can), you can override the back button and use something like
UIViewController * prev = self.navigationController.viewControllers[self.navigationController.viewControllers.count -2 ]
[self.navigationController popToViewController:prev animated:YES]
With a modal view controller, you may try something like (I haven't tried but it may work)
[self.presentingViewController.navigationController popViewControllerAnimated:YES]
You should write one of these code into the target action of your close button.
iOS doesn't maintain a global stack of controllers in the way that Android does. Each app shows a controller at its root, and that one is responsible for showing the other controllers in the app. Controllers can display other controllers modally using presentViewcontroller:animated:completion: but the presenting controller remains underneath the presented one.
If your current controller is the root controller, then instead of using presentViewcontroller:animated:completion: you'd just do this:
self.view.window.rootViewController = nextViewController;
It's very common for the root controller to be a UINavigationController, which does manage a stack of controllers. If that is the case, and if your current controller is at the top of the stack, you'd do this:
[self.navigationController popViewControllerAnimated:NO];
[self.navigationController pushViewController:nextViewController animated:YES];
If your setup is different, you'd do something different; it's hard to say what without knowing more. But it's most likely that you'd be in the UINavigationController case.
In the viewDidAppear of your nextviewcontroller you could add :
-(void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
NSArray *controllers = self.navigationController.viewControllers;
NSMutableArray *newViewControllers = [NSMutableArray arrayWithArray:controllers];
[newViewControllers removeObjectAtIndex:[controllers count]-2];
self.navigationController.viewControllers = newViewControllers;
}
There is nothing available like this in iOS but you can achieve it doing something like below
NSArray *viewControllers=[self.navigationController viewControllers];
NSMutableArray *newControllers=[[NSMutableArray alloc] init];
for(int i=[viewControllers indexOfObject:self];i<viewControllers.count;i++){
[newControllers addObject:[viewControllers objectAtIndex:i]];
}
[self.navigationController setViewControllers:[[NSArray alloc] initWithArray:newControllers]];
I have tried the method of storing all the view controllers in an array but it didn't work for me . When you try popViewController it will move to the View Controller which is last in the stack.
You can make 2 navigation controllers and switch between them and also switch between the view controllers of a particular Navigation Controller.
For eg.
You can switch between 2 Navigation Controller using the following code:
FirstNavController *fisrtView=[storyboard instantiateViewControllerWithIdentifier:#"firstnavcontroller"];
self.window.rootViewController = firstView;
}else{
SecondNavController *secondView=[storyboard instantiateViewControllerWithIdentifier:#"loginnavcontroller"];
self.window.rootViewController = secondView;
}
If your FirstNavController has 2 ViewControllers then you can switch between them using pushViewController
SecondViewController *sc = [self.storyboard instantiateViewControllerWithIdentifier:#"secondviewcontroller"];
[[self navigationController] pushViewController:sc animated:YES];
and popViewController
[self.navigationController popViewControllerAnimated:YES];
I have a UITabBarController that contains a UINavigationController each as TabbarItems.
Each UINavigationController has it's own UIViewController as the rootViewController.
Now, one of the rootViewControllers processes some information and sends it to another rootViewController.
Then, this rootViewController further processes that info and displays it on it's UI.
Till now, i have done this:
//from the current VC, taken the reference of the viewController
//to which i have to pass the data.
UINavigationController *controller = (UINavigationController *)self.parentViewController;
UITabBarController *cont = (UITabBarController *)controller.parentViewController;
//called the method of the target viewController that will do further processing
//(to which i will pass the data).
CustomerCareViewController *customerCare = (CustomerCareViewController *)[[cont viewControllers] objectAtIndex:0];
[customerCare setSRNumber:SRNum];
Now, I need to display the processed info (that will be shown on the UI of the target controller)
If you just want to switch from one tab to the other, use
self.tabBarController.selectedIndex = newIndex;
try this
[objAppDel.tabBarController setSelectedViewController:[[objAppDel.tabBarController viewControllers] objectAtIndex:1]];
hope this will help you.
I've been struggling with this for quite some time and I can't seem to find anything here that directly relates. My goal is to pass a core data object from the login screen to my first view. My first view is linked to a navigation controller and the navigation controller is the first tab on a tab bar controller.
Through prepareForSegue, I can pass the object no problem to the tab bar controller but that's when things get confusing, how do I pass the object stored in the tab bar controller to the navigation controller?
Any help would be much much appreciated!
The TabBar is holding the array of ViewController and since your ViewController is inside NavigationController you can use this code to pass the object you want to the ViewController inside the NavigationControllerfrom prepareForSegue
UITabBarController *tabBarCtr = segue.destinationViewController;
UINavigationController *navigationController = [[tabBarCtr viewControllers] objectAtIndex:0];
YourViewControllerClass *viewControl = [[navigationController viewControllers] objectAtIndex:0];
viewControl.myObject = self.myObject
This works too:
UITabBarController *tabBarCtr = segue.destinationViewController;
SearchItemTypeViewController *viewControl = [[tabBarCtr viewControllers] objectAtIndex:0];
I am working on an app that at launch checks for valid login credentials, and if they are found and not expired the main split view controller is displayed, and if not a login screen should be displayed.
Each part is working fine separately, but I am struggling with the best way at launch time to select the proper view to display.
I have tried setting up a modal segue from the root view controller, and in my application:didFinishLaunchingWithOptions: function in the App Delegate, calling this:
// Segue to the login view controller...
if (loginNeeded) {
[self.window.rootViewController performSegueWithIdentifier:#"LoginScreen" sender:self];
}
This logically should work, but triggering segues from within the app delegate seems to be impossible.
What is the ideal place and technique for handling this?
You could try a custom segue, as per this post hiding-a-segue-on-login-process.
Alternatively if you're desperate to have the login display before the split view controller loads try something along the following lines...
Create your login screen on the main storyboard as, say, a subclass of UIViewController. Make sure it is the initial scene (check Is Initial View Controller).
On the storyboard, create a new segue from your login class to the original SplitViewController. Give it an identifier, 'Load SplitViewController' and a segue custom class name which we'll call FullyReplaceSegue.
In your login class .m file, add code to be called once the user has logged in:
[self performSegueWithIdentifier:#"Load SplitViewController" sender:self];
Create the new segue class, based on UIStoryboardSegue and name it FullyReplaceSegue as per above.
.h file
#import <UIKit/UIKit.h>
#interface : UIStoryboardSegue
#end
.m file
#import "FullyReplaceSegue.h"
#implementation FullyReplaceSegue
- (void)perform
{
UIViewController *dest = (UIViewController *) super.destinationViewController;
UIWindow *window = [UIApplication sharedApplication].keyWindow;
window.rootViewController = dest;
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
UISplitViewController *splitViewController = (UISplitViewController *)dest; // assumes we're transitioning to a UISplitViewController!
UINavigationController *navigationController = [splitViewController.viewControllers lastObject];
splitViewController.delegate = (id)navigationController.topViewController;
}
}
#end
Here's how I did it.
In didFinishLaunchingWithOptions:
//save the root view controller
[[self window] makeKeyAndVisible];
UINavigationController *navigationController = (UINavigationController*) self.window.rootViewController;
rootController = [[navigationController viewControllers] objectAtIndex:0];
Somewhere else in the app delegate:
[rootController performSegueWithIdentifier:#"fileSegueID" sender:self];
Then, in the storyboard, create a segue from the view that gets assigned as "rootController", to the desired optional view, and give that new segue the id fileSegueID. It takes some debugging to make sure the rootController variable gets assigned to the correct view.
Maybe a little late, but I was looking for the same suggestions. Here's what I wound up doing.
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Signup" bundle:nil];
if(isLoggedIn) {
UINavigationController *navigationController = (UINavigationController*) self.window.rootViewController;
IndexController *ivc = [storyboard instantiateViewControllerWithIdentifier:#"IndexController"];
[navigationController pushViewController:ivc animated:NO];
}
Why don't you load the screen that would be visible assuming proper and non-expired log-in credentials (by setting it as the root view controller of the window), and then in viewDidLoad of that first view controller, check if an update to the login credentials are needed. If so, segue into the login view controller.
Yes, it can be used, if you get a reference to the segue's parent view controller. You can get it like this:
UINavigationController *navigationController = (UINavigationController*) self.window.rootViewController;
[[[navigationController viewControllers] objectAtIndex:0] performSegueWithIdentifier:#"LoginScreen" sender:self];
This will only work if the index in viewControllers array matches the one of your view controller and if it exists of course. In this case is the first one (in the array and storyboard).
The segue ("LoginScreen") must not be attached to an action. The way you do this is by control-dragging from the file owner icon at the bottom of the storyboard scene to the destination scene. A popup will appear that will ask for an option in “Manual Segue”; pick “Push” as the type. Tap on the little square and make sure you’re in the Attributes Inspector. Give it an identifier which you will use to refer to it in code.