Okay, I understand how to work delegation in a modal view to send a message to the parentviewcontroller but what if I wanted to do that with 2 views that dont have that parent-child relationship?
I have a navigation controller that flips over a modal view and then that modal view pushes a new view controller. How do I let that pushed view controller talk to the navigation controller. The modal view code that I have been using places this in the parent:
-(IBAction)pressedUnitAddy {
UnitAddyView *unitVC = [[UnitAddyView alloc] init];
unitVC.delegate = self;
UINavigationController* theNavController = [[UINavigationController alloc]initWithRootViewController:unitVC];
theNavController.modalTransitionStyle = UIModalTransitionStylePartialCurl;
[self presentModalViewController:theNavController animated:YES];
[unitVC release];
[theNavController release];
}
-(void)didDismissUnitAddyView {
[self dismissModalViewControllerAnimated:YES];
}
....and then I call the didDismissUnitAddyView from the UnitAddyView. Now, I am not trying to dismiss any views with what I am trying to do but I do want that pushed view controller to be able to speak to the navigation controller. How would I do that?
View controllers have a property, navigationController, that is nil if they're not pushed onto a navigation controller and is a pointer to the navigation if they are. Does that answer your question?
All I was trying to do was to reload the data on the nav controller screen. The UIViewController and the nav controller we not directly connected - they were separated through a modalview. All I did, and I should have thought of this earlier, was set the modal view's delegate to the nav controller and to call a method to reload the nav controller when the modal view is dismissed.
Related
I'm trying to add some navigation controller in my app, it's sth likes:
in my index page view controller, I try to initialize the navigation controller like this:
-(void)viewDidLoad{
...
//allocate a navigation controller.
myNavigationController = [[UINavigationController alloc]init];
myNavigationController.delegate = self;
myNavigationController.navigationBar.hidden = YES;
[self.view addSubview:myNavigationController.view];
[myNavigationController pushViewController:tabViewController animated:YES];
[self presentModalViewController:myNavigationController animated:YES];
}
Here, index page view controller is the root view controller of my app, it's just a common UIViewController here.
[myNavigationController pushViewController:tabViewController animated:YES];
The tabViewController here I've pushed into the navigation controller is a custom tabview controller which makes use of a container view to hold the tab button and also holds an navigation controller for tab switching.
The problem here is:
myNavigationController.navigationBar.hidden = YES;
since I've make the navigation bar invisible, it doesn't show when my custom view controller shows, but when I'd like to switch to some other view controller with the navigation controller and I also want the navigation bar visible:
myNavigationController.navigationBar.hidden = NO;
MyViewController *toSwitchNC = [[MyViewController alloc]init];
[myNavigationController pushViewController:toSwitchNC animated:YES];
The navigation bar would never show any more. I've also tried to put:
self.navigationController.navigationBar.hidden = NO
in MyViewController's viewDidLoad, ViewDidAppear or even in the navigation controller's delegate method, it didn't show the navigation bar neither.
So what's wrong with it? Why I initialized the navigation bar to be invisible at first, it will never show again even I set the hidden flag to be false?
Okay, I've got this fixed by removing the navigation controller container in my index page view controller. This might be a stupid question, since apple've formally stated in the developer document that the navigation view controller should be place as root as possible in the view stack. Since IOS is a closed system, who knows WTH is going on under-beneath except Apple.
I apologize I am new to iphone programming.
I have created a Master-Detail Iphone application (so Navigation Controller came with the project). I segue to a new view controller I created through a UIBarButtonItem on the masterviewcontroller. However unlike the detailviewcontroller (that came with the project) I can not seem to get the navigationitem (or navigationbar?) to display on the view even though it appears in the scene list of my storyboard.
Heres some code and a screenshot:
In my masterviewcontroller.m viewdidload() function
UIBarButtonItem *settingsButton = [[UIBarButtonItem alloc] initWithTitle:#"Settings" style:normal target:self action:#selector(goToSettings:)];
self.navigationItem.leftBarButtonItem = settingsButton;
in my masterviewcontroller.m
- (IBAction)goToSettings:(id)sender{
[self performSegueWithIdentifier:#"SettingsSegue" sender:self];
}
I tried adding a title to the navigationitem during the viewDidLoad function of the new viewcontroller.m class i created (mentioned in this Link but it didn't work)
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
self.navigationItem.title = #"Settings";
self.navigationItem.leftBarButtonItem = self.editButtonItem;
}
But it still shows up in my storyboard ( it shows up in the list under the scene but not in the display of the view)
So my question is why is it now showing up and how do I get it to? I want a back button like my detail view controller that came with the master-detail project.
EDIT#1
I have added a check for whether navigation controller is nil and it is not nil (the if statement is never entered) I also tried changing the navigation item to back and removing and none has worked.
if(self.navigationItem == nil)
{
[ self.navigationItem init];
}
self.navigationItem.title = #"Settings";
self.navigationItem.leftBarButtonItem = self.navigationItem.backBarButtonItem;
Now that I have enough reputation to show an image I can show that the navigation item shows up in the list but doesnt show up on the view
The Navigation item did not show up because of the "style" of my segue.
The segue that moved the scene from the master view controller to the settings view controller was set to 'modal'. It has to be set to 'push'. This is done from the storyboard on the utilities pane
You have to change your Segue Style by doing this:
Select the Segue in your Storyboard;
Go to the Attributes inspector (on the right pane tabs);
Change the Style attribute to Push.
It will make the screen roll from right to left and the Navigation bar will appear sliding.
With Modal, the screen come from bottom to the top of the screen and it will not let the Navigation bar appears.
The problem in my case was that the Navigation controller wasn't the "initial View Controller"
So I had to do this
You have verified that your navigation controller listed in the viewDidLoad method is not nil?
Assuming that you do correctly have a self.navigationItem that is non-nil, it appears that you are incorrectly setting your self.navigationItem.leftBarButtonItem to an editButtonItem, instead try removing this all together!
If removing it does not solve the problem try:
self.navigationItem.leftBarButtonItem = self.navigationItem.backBarButtonItem;
Please check if your view controller is the root view controller of the navigation controller. You cant directly present a view controller as a modal view controller. You have to make your view controller as the root view controller of a navigation controller and then present your navigation controller as the modal view controller.
// Create the root view controller for the navigation controller
// The new view controller configures a Cancel and Done button for the
// navigation bar.
YourViewController *addController = [[YourViewController alloc]
init];
// Configure the YourViewController.
// Create the navigation controller and present it.
UINavigationController *navigationController = [[UINavigationController alloc]
initWithRootViewController:addController];
[self presentViewController:navigationController animated:YES completion: nil];
You need to have a Navigation Controller and a View Controller.
"The navigation controller manages the navigation bar at the top of the interface and an optional toolbar at the bottom of the interface. The navigation bar is always present and is managed by the navigation controller itself, which updates the navigation bar using the content provided by its child view controllers. When the isToolbarHidden property is false, the navigation controller similarly updates the toolbar with contents provided by the topmost view controller."
https://developer.apple.com/documentation/uikit/uinavigationcontroller
The Navigation Item also appears in the View Controller Scene you can look for it there and edit it too
This is what I am doing. I have a tabBarControllerOne with 5 tabs. On clicking one of the tabs, I present a modal view controller, which has a navigationBar and a TabBarControllerTwo (with 3 tabs). These three tabs are the matter for concern here.
In the 5th Tab of tabBarController I show modalViewController as
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self.nextTabView];
// navController.navigationBarHidden = YES;
navController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
NSLog(#"Displauing the navcontroller before pushing %#", navController);
[self presentModalViewController:navController animated:NO];
Here, nextTabView is a tabBarController with 3 tabs. The views work. In the views, if I try something like.
self.navigationController.navigationBarHidden = YES;
[self.navigationController pushViewController: someController animated:YES];
// nothing works.
If I NSLog, it displays self.navigationController as (null)
Can someone tell me why this is not working ?
Embedding a UITabBarController inside a UINavigationController is not supported. Apple has a careful hierarchy of container view controllers, and a UITabBarController must be the root of its view controller hierarchy.
Additionally, as Joe points out, your views don't belong to the navigation controller; they belong to the tab bar controller, so their navigationController property is not set.
The modal view controller does not belong to a UINavigationController stack therefore the property is not set. You will want to use delegation to notify the creating controller when something is selected then that controller can properly push the next controller on to the stack.
UIViewController Reference:
Discussion
Only returns a navigation controller if the view controller
is in its stack. This property is nil if a navigation controller
cannot be found.
I am showing a modal view which is a UITableViewController class. For some reason it won't show the navigation bar when I show it. Here is my code:
SettingsCreateAccount *detailViewController = [[SettingsCreateAccount alloc] initWithStyle:UITableViewStyleGrouped];
detailViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
detailViewController.navigationController.navigationBarHidden = NO;
[self.navigationController presentModalViewController:detailViewController animated:YES];
detailViewController = nil;
[detailViewController release];
I thought it was shown by default? If it helps, I am calling this from another class that is also a UITableViewController managed by a UINavigationController. Ideas?
When you present a modal view controller it does not use any existing navigation controllers or navigation bars. If all you want is to display a navigation bar, you need to add the navigation bar as a subview of your modal view and present it as you're doing.
If you want to present a modal view controller with navigation functionality, you need to present a modal navigation controller containing your detail view controller instead, like so:
SettingsCreateAccount *detailViewController = [[SettingsCreateAccount alloc] initWithStyle:UITableViewStyleGrouped];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:detailViewController];
[detailViewController release];
navController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:navController animated:YES];
[navController release];
Your modal controller will manage its own navigation stack.
Here is one way to display navigation bar for those who are using storyboards, suggested by Apple's Tutorial on Storyboard.
Because a modal view controller doesn’t get added to the navigation stack, it doesn’t get a navigation bar from the table view controller’s navigation controller. To give the view controller a navigation bar when presented modally, embed it in its own navigation controller.
In the outline view, select View Controller.
With the view controller selected, choose Editor > Embed In > Navigation Controller.
On iOS 7 and you just want a navigation bar on your modal view controller to show a title and some buttons? Try this magic in your UITableViewController:
// in the .h
#property (strong) UINavigationBar* navigationBar;
//in the .m
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationItem.title = #"Awesome";
self.navigationBar = [[UINavigationBar alloc] initWithFrame:CGRectZero];
[self.view addSubview:_navigationBar];
[self.navigationBar pushNavigationItem:self.navigationItem animated:NO];
}
-(void)layoutNavigationBar{
self.navigationBar.frame = CGRectMake(0, self.tableView.contentOffset.y, self.tableView.frame.size.width, self.topLayoutGuide.length + 44);
self.tableView.contentInset = UIEdgeInsetsMake(self.navigationBar.frame.size.height, 0, 0, 0);
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
//no need to call super
[self layoutNavigationBar];
}
-(void)viewDidLayoutSubviews{
[super viewDidLayoutSubviews];
[self layoutNavigationBar];
}
I want to share how the accepted solution can be used in projects with storyboards:
The simple approach is to put in a storyboard blank navigation controller before the VC which is to be presented modally, so the relations look like:
(Presenter VC) -> presents modally -> (navigation controller having a controller to be presented as its root).
We've tried this approach for a while and noticed that our storyboards become "polluted" by a large number of such intermediate navigation controllers when each! of them is used exclusively for one! presentation of some other controller, that we want to be presented modally with navigation bar.
Our current solution is to encapsulate the code from accepted answer to a custom segue:
#import "ModalPresentationWithNavigationBarSegue.h"
#implementation ModalPresentationWithNavigationBarSegue
- (void)perform {
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:self.destinationViewController];
[self.sourceViewController presentViewController:navigationController animated:YES completion:nil];
}
#end
Having this segue in our project we do not create intermediate navigation controllers in our storyboards anymore, we just use this ModalPresentationWithNavigationBarSegue like:
Presenter VC --> Presentee VC
I hope that this answer will be helpful to people who like to avoid unnecessary duplication in their apps storyboards.
I just wanted to add something to what #Scott said. His answer is definitely the easiest and most accepted way of doing it now with Storyboards, iOS 7 and 8... (and soon, 9).
Definitely adding a view controller to the Storyboard and Embedding it as described by #Scott is the right way to go.
Then, just add the segue by control-dragging from the source view controller to the target (the one you want to show modally), select "Present Modally" when the little view appears with the choices for the type of segue. Probably good to give it a name too (in the example below I use "presentMyModalViewController").
One thing that I needed that was missing is #Scott's case is when you want to actually pass on some data to that modally-presented view controller that is embedded in the navigation controller.
If you grab the segue.destinationViewController, it will be a UINavigationController, not the controller you embedded in the UINavigationController.
So, to get at the embedded view controller inside the navigation controller, here's what I did:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:#"presentMyModalViewController"]) {
// This could be collapsed, but it's a little easier to see
// what's going on written out this way.
// First get the destination view controller, which will be a UINavigationController
UINavigationController *nvc = (UINavigationController *)segue.destinationViewController;
// To get the view controller we're interested in, grab the navigation controller's "topViewController" property
MyModalViewController *vc = (EmailReceiptViewController *)[nvc topViewController];
// Now that we have the reference to our view controller, we can set its properties here:
vc.myAwesomeProperty = #"awesome!";
}
}
Hope this helps!
If you only need a NavigationBar, you can add an instance of UINavigationBar and assign BarItems to it.
I'm changing the back button item title in the viewDidAppear of a controller in the following way:
self.navigationController.navigationBar.backItem.title = #"Previous";
It changes the tittle properly, but the I'm having a strange behaviour. When I select the "previous" button, it changes the tittle of the controller that is up in the stack (i.e the parent controller now has the title "Previous".
Do you now why this happened?
When you're using a navigation controller, calling [self setTitle:#"Title"]; inside of any view controller in the stack will set the navigation bar title. This is also the title used by default for the back button when you've pushed a new view controller. Apparently, from what you are experiencing, explicitly setting the title of the backItem, also sets it for the navigation bar title for the previous view controller overriding whatever what specified in the call to -setTitle in the view controller.
You will probably be better off just managing the title from within the view controllers in your navigation stack. When you go to push a new view controller, do this:
[self setTitle:#"Previous"];
NextViewController *controller = [[NextViewController alloc] init];
[[self navigationController] pushViewController:controller animated:YES];
[controller release], controller = nil;
Now, when the next view controller displays, the back button with say "Previous". Now, you just need to change it back to whatever its real title should be in -viewWillAppear:
- (void)viewWillAppear:(BOOL)animated;
{
[self setTitle:#"Real Title"];
[super viewWillAppear:animated];
}
It may feel a little hacky, but it's better than trying to override the navigation bar functionality. Wrestling with the nav bar/nav controller stack can prove very frustrating.
Best regards.