I would like to know what kind of trick to use for "not pushing" a view controller into the navigation controller stack (iOS)
I have this :
If user is not logged, show view A then show B
If user is logged, show B
As I am using the storyboard, I used a performSegue if the user is logged so he goes directly to B. But with this method, the Navigation Controller gets a push of view A in the stack.
I was thinking of poping out a level of the stack in some void (but I don't know how to do this).
I was also thinking of not pushing the view into the nav controller stack (but I don't know how to do this).
Thanks
Update :
I tried this :
//The view B
TabBarMain* mainViewController = [[TabBarMain alloc] init];
//If already logged in
if([username length] == 0)
{
NSArray *viewControllers = [NSArray arrayWithObject:mainViewController];
[self.navigationController setViewControllers:viewControllers animated:NO];
}
The problem of this code is that it shows me a black screen (doesn't crash). It seems that I need to init something and I have nothing in my TabBarMain.m, I don't know what to write in there. This TabBarMain is linked to the Tab Bar Controller of the Storyboard.
Is there no other way ?
Try this on for size in your rootViewController's viewDidLoad.
- (void)viewDidLoad
{
NSArray *viewControllers
if (logged) {
NSArray *viewControllers = [NSArray arrayWithObject:viewControllerB];
} else {
NSArray *viewControllers = [NSArray arrayWithObject:viewControllerA];
}
[self.navigationController setViewControllers:viewControllers animated:NO];
}
Since your viewController is linked in Storyboard and not instantiated in code you need to instantiate it from the storyboard not your empty code. Make sure the identifier matches the identifier for your ViewController in your storyboard.
TabBarMain *mainViewController = [[UIStoryboard storyboardWithName:#"MainStoryboard" bundle:NULL] instantiateViewControllerWithIdentifier:#"tabBarMain"];
Related
Possibly simple request here but I can't find the solution and it is bugging me for days.
I'm building simple options page where users could jump to desired page and I'm using UINavigationController instance to manage hierarchy. My storyboard looks like this:
Viewcontrollers are connected with push segues fired on next button, while I use [self.navigationController popViewControllerAnimated:YES] for previous button. If I connect, for instance, button labeled 2 on 5VC with 2VC through push segue, I get to the second page, but if I want to use previous button I will land to options page or 5VC which is something I don't want. Instead, I would like to be able to use previous button to go to first page, while on second page.
The way I see it, if I am on third page (3VC) and I call options page (5VC) and select button 3, system should stack 1VC-2VC and present 3VC, so I would be able to go to 2VC through [self.navigationController popViewControllerAnimated:YES] request.
I think the solution is somehow connected with setViewControllers:(NSArray *)viewControllers animated:(BOOL)animated, but I don't know the syntax how to make things work.
You have 3 cases
Back to one of ancestors in the middle with push
case 5VC=>2VC, 5VC=>3VC:
NSArray *vcs = self.navigationController.viewControllers;
for(NSInteger i = vcs.count - 2; i > 0; i--) {
// find the target and its parent view controller
// i.e. class of 2VC is ViewController2
if([vcs[i] isKindOfClass:[ViewController2 class]]) {
UIViewController *target = vcs[i];
UIViewController *parent = vcs[i - 1];
// pop to its parent view controller with NO animation
[self.navigationController popToViewController:parent animated:NO];
// push the target from its parent
[self.navigationController pushViewController:target animated:YES];
return;
}
}
Back to the root view controller with push
case 5VC=>1VC:
UIViewController *root = self.navigationController.viewControllers.firstObject;
// reset view controllers stack with self as root.
[self.navigationController setViewControllers:#[self] animated:NO];
// push target from self
[self.navigationController pushViewController:root animated:YES];
// reset navigation stack with target as root.
[self.navigationController setViewControllers:#[root] animated:NO];
Push new VC from one of ancestors
case 5VC=>4VC
NSArray *vcs = self.navigationController.viewControllers;
for(NSInteger i = vcs.count - 1; i >= 0; i--) {
// find the parent view controller
if([vcs[i] isKindOfClass:[ViewController3 class]]) {
UIViewController *parent = vcs[i];
// pop to the parent with NO animation
[self.navigationController popToViewController:parent animated:NO];
// perform segue from the parent
[parent performSegueWithIdentifier:#"push4VC" sender:self];
return;
}
}
On the particular your case(5VC=>4VC), you know 3VC is the self's parent, you can get the parent directly:
NSArray *vcs = self.navigationController.viewControllers;
UIViewController *parent = vcs[vcs.count - 2]; // [vcs.count-1] is self.
[self.navigationController popToViewController:parent animated:NO];
[parent performSegueWithIdentifier:#"push4VC" sender:self];
I present a modal view controller for various UI settings in an iOS app. One of those settings allows the user to select a different main view. When they hit "Done" I want to dismiss the modal view and have the newly-selected view controller appear, without a momentary delay where the old view controller segues to the new view controller. How could this be implemented?
Update:
Here is a method I successfully implemented using Eugene's technique, but without the app delegate. Instead, this implementation is specific to my scenario where a view controller in a navigation stack presents the modal view controller in a Utility app.
- (void)swapFrontSideViewController;
{
UINavigationController *navigationVC = (UINavigationController *)[self presentingViewController];
NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:navigationVC.viewControllers];
UIViewControllerSubclass *selectedViewController = nil;
if ([self.selectedFrontSide isEqualToString:FRONT_SIDE_NAME1]) {
selectedViewController = [self.storyboard instantiateViewControllerWithIdentifier:FRONT_SIDE_NAME1];
} else if ([self.selectedFrontSide isEqualToString:FRONT_SIDE_NAME2]) {
selectedViewController = [self.storyboard instantiateViewControllerWithIdentifier:FRONT_SIDE_NAME2];
}
if (selectedViewController) {
[viewControllers replaceObjectAtIndex:viewControllers.count -1 withObject:selectedViewController];
[navigationVC setViewControllers:viewControllers];
self.delegate = selectedViewController;
} else {
NSLog(#"Error: Undefined Front Side Selected.");
}
}
- (IBAction)doDismiss:(id)sender {
AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate; // Get the app delegate
NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:appDelegate.navigationController.viewControllers]; // fetch its navigationController viewControllers stack
UIViewController *replacementController; //initialize replacement controller
[viewControllers replaceObjectAtIndex:viewControllers.count -1 withObject:replacementController]; // replace the top view controller in stack with the replacement one
[appDelegate.navigationController setViewControllers:viewControllers]; //change the stack
[self dismissModalViewControllerAnimated:YES];
}
I have a navigation view controller that pushes "viewController1" properly. Then, from "viewController1", goToApp function is called in order to push "appViewController". Function goToApp is executed but aplication remains at same view, "viewControlller1". How to push it? Thank you.
from viewController1:
navigationViewController *theInstance = [[navigationViewController alloc] init];
[theInstance goToApp];
in navigationViewController:
-(void)goToApp {
appViewController *AppsViewController = [[appViewController alloc] initWithNibName:#"appViewController" bundle:nil];
[[self navController] pushViewController:AppsViewController animated:YES];
[AppsViewController release];
}
goToApp executed but appViewController not launched.
You should not create a new UINavigationController in viewController1. You should get it through the property navigationController. That property will return the UINavigationController that has the UIViewController on it's stack (if any, so it can be nil).
UINavigationController * theInstance = self.navigationController;
[theInstance goToApp];
See: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html property navigationController.
Besides that, it is a better convention to name your pointers correctly to what they represent. I would suggest to rename theInstance to currentNavigationController or just navigationController.
I'm trying to create another UINavigationBar in my project, but it seems that I'm missing some key detail. When the application first loads, it does have it's own navigation system, but now I'm trying to add another navigation to a modal.
Many tutorials show you need to connect the view to the [self window], which only seems to work in the AppDelegate files, but when I've tried placing the code* in viewDidLoad, I can never seem to build without any errors.
I've seen this in multiple apps, but how is this done (programmatically or with IBuilder)?
Thanks!
Example code I've tried in viewDidLoad
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:[self viewController]];
[self.window addSubview:navigationController.view];
You don't show enough code to be able to understand how you do it, but it seems to me that you are showing a controller modally, then trying to add as a subview to its view a navigation controller.
You can try and directly push modally your navigation controller (from your app delegate or where it makes sense for your app):
(IBAction) navigateToSecondaryViewController {
if (secondaryViewController == nil) {
informationTableViewController = [[SecondaryViewController alloc]
initWithNibName:#"SecondaryViewController"
bundle:[NSBundle mainBundle]];
secondaryViewController.delegate = self;
}
if (navController == nil) {
navController = [[UINavigationController alloc]
initWithRootViewController:secondaryViewController];
}
[self presentModalViewController:navController animated:YES];
}
Full example here.
I am creating my Nav and TabBar in code at launch via:
IN : myAppDelegate.m
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// set up a local nav controller which we will reuse for each view controller
UINavigationController *localNavigationController;
// create tab bar controller and array to hold the view controllers
tabBarController = [[UITabBarController alloc] init];
NSMutableArray *localControllersArray = [[NSMutableArray alloc] initWithCapacity:4];
// setup the first view controller (Root view controller)
RootViewController *myViewController;
myViewController = [[RootViewController alloc] initWithTabBar];
// create the nav controller and add the root view controller as its first view
localNavigationController = [[UINavigationController alloc] initWithRootViewController:myViewController];
// add the new nav controller (with the root view controller inside it)
// to the array of controllers
[localControllersArray addObject:localNavigationController];
// release since we are done with this for now
[localNavigationController release];
[myViewController release];
// setup the first view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image1.png"];
resortsListViewController.navigationItem.title=#"Category1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
// setup the second view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category2";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image2.png"];
resortsListViewController.navigationItem.title=#"Category2";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
// setup the third view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category3";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image3.png"];
resortsListViewController.navigationItem.title=#"Category3";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
[resortsListViewController release];
// load up our tab bar controller with the view controllers
tabBarController.viewControllers = localControllersArray;
// release the array because the tab bar controller now has it
[localControllersArray release];
// add the tabBarController as a subview in the window
[window addSubview:tabBarController.view];
// need this last line to display the window (and tab bar controller)
[window makeKeyAndVisible];
}
As you see, I am re-using ResortsListViewController for different category displays (resorts with Beaches, resorts with Pools, resorts with espresso bars) ... now, without harassing me (grin) about the silliness of my categories (cos this is a test app) I need need to do several things:
I need to be able to know which tab click caused the ResortsListViewController to be displayed. I was hoping to use TAG but "initWithRootViewController" does not have the "tag" control. So, if i use an imagefilename that is the category name, I can use that filename to distinguish categories...or even navigationItem name. I need to know if there is a way for ResortsListViewController to know which tabbar item click caused it's display. I thought to look for a "action" that I could assign to the tabbar item, but that is not the way tabbarcontroller works.
When clicking from one tab to another, the view does indeed change, the title of ResortsListViewController changes, etc...but the TABLEVIEW it holds does not clear and display any new data. Searching the web I have found a possible solution:
http://discussions.apple.com/thread.jspa?threadID=1529769&tstart=0
basically saying:
In order for UINavigationControllers
to send
"viewWill/Did/Appear/Disappear"
messages, it needs to have received
"viewWill/Did/Appear/Disappear" from
its container.
What is the container for my UINavigationControllers in this situation? myAppDelegate is defined in the .h file as:
NSObject <UIApplicationDelegate, CLLocationManagerDelegate>
and does not have a:
- (void)viewWillAppear:(BOOL)animated {
}
section. When I add one it says "NSObject may not respond to -viewWillAppear" in the debugger.
Any help out there?
1) This is fairly simple. You need to set the delegate property for the UITabBarController. You would set this to the controller object that owns your tabbarcontroller (or your app delegate if that is your setup). Whichever object is set as the delegate would then receive:
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
AND
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
to manage tab selections. Place one of these methods in the implementation of whatever object you set as the delegate (you would want it to be the object that owns all of the controllers).
2) If you have a UIViewController that appears as a tab selection (such as ResortsListViewController) then you would need to put the viewWillAppear method in the controller implementation yourself:
#implementation ResortsListViewController
- (id)initWithNibName:(NSString *)name bundle:(NSBundle *)bundle {
...
}
... etc. ....
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[table reloadData];
}
...
#end
Let me know if I misunderstood the second part of your question.
Okay, here goes: This is the correct answer to the question, however, it did not end up being this hard. All I had to do was the following:
Create a property in ResortViewController of type int with variable name whichChoice (for instance). Then address it in the setup of the TabBarController a la:
// setup the first view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
// START HERE IS THE CHANGE
resortsListViewController.whichChoice = 1;
// END HERE IS THE CHANGE
resortsListViewController.title = #"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image1.png"];
resortsListViewController.navigationItem.title=#"Category1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
To find out which tab was clicked when my resortsListViewController takes over, I simply query the class variable: whichChoice to get the answer.
Things like this are so simple you skip over them. I thought you had to pass the variable in an action and specify where it would go with the target like you do in other objects -- but when you set things up ahead of time you do not have to do that. Now, having said that, dynamically setting "whichChoice" is not so easy without a lot more thought...but setting it to a variable KNOWN at setup is fine.
For answer #2, I simply put a variable style of IBOutlet in my class, hooked it up to the table, and then followed your instructions, because without the variable in the IBOutlet and hooking it up to the table, there is no reference to the table view. For some reason hooking up the table simply to the VIEW "Referencing Outlet" and calling [self.tableview reloadData] did not do the job.
But for the most part, your answers were right and led me in the right direction. As an aside, I really hate that you have to right-click and drag from here-to-there in IB if you have an IB element you built. You should be able to hook it up in code using it's ObjectId (or something). That would be more in line with programmers. I know IB is made to allow programming to be easier for designers, but gee wilikers..it is hard to wrap my mind around! I end up dropping IB and creating elements in code most of time time...which I do not know if is as fast to execute. I tend to think not...but have no proof to the contrary.