I am using a sample ViewController that is displayed in the sample program as a presentModalViewController. However, I want to use pushViewController on the UIViewController instead. The problem is that when I switch to pushViewController, the ViewController no displays properly. Functions in the ViewController are called, but I don't see anything. I change back to presentModalViewController and everything works.
The question is what do I need to do to make pushViewController work?
FCVC *fcVC;
NSArray *array = [[NSBundle mainBundle] loadNibNamed:#"fcVC"
owner:self
options:nil];
fcVC = [array objectAtIndex:0];
A. [self presentModalViewController:fcVC animated:YES]; // "WORKS"
or
B. [self.navigationController pushViewController:fcVC animated:YES]; // "Doesn't work
Do you have a UINavigationController actually set up? "self" should be a viewController that is loaded inside UINavigationController.
To create a NavigationController in a view-based application you have to set the NavigationController in the delegate class.
Like This
In delegate .h class
MyViewController *viewController;
In delegate .m class
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UINavigationController *nvcontrol =[[UINavigationController alloc] initWithRootViewController:viewController];
[window addSubview:nvcontrol.view];
[window makeKeyAndVisible];
}
Here "MyViewController" should be replaced by your viewcontroller.
All The Best.
Related
I am seeing a strange app behaviour when I try to push some view controller from uitableviewcontroller subclass.
Let me explain it first. I have created main nib which is linked to rootViewController (appDelegate) that is inside navigationController. In that nib a have added a UITableView and a custom UITableViewController subclass News_TableViewController like it's shown in the screenshot:
When I try to execute the code bellow I get nothing:
My_WebView *webView = [[My_WebView alloc] initWithNibName:#"My_WebView" bundle:nil];
[self.navigationController pushViewController:webView animated:YES];
Then I checked self.navigationController object but i gives me NULL:
NSLog(#"OBJ: %#",self.navigationController);
How is that I am not geting the reference to the navigationController despite of my custom class actually lives under navigationController ?
Thanks
As you've mentioned, News_TableViewController is a UITableViewController, hence a UIViewController. I think you did'nt initialize the navigationController! A recommended way is to init the navigationController in your appDelegate class' delegate method as follows:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
RootViewController *rootViewController = [[RootViewController alloc]init];
_navigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
return YES;
}
where RootViewController is the News_TableViewController class.
I have a root view controller which should load another view controller as soon as it is done loading (i.e. in the viewDidLoad method).
I am using the UINavigationController in order to push a new view controller onto the stack:
In my rootviewcontrollerappdelegate:
-(void) viewDidLoad{
LoginViewController* lvc = [[LoginViewController alloc]init];
[self.navigationController pushViewController:lvc animated:NO];
}
I have textfields and buttons in the view controller to be loaded. The above doesn't seem to work however...It loads just a blank grey screen and no UINavigation bar is present. If I comment out the second line (pushViewController line), then I see the navigation bar. So I think it is loading something, but the items in the view controller being loaded are not being shown...Any ideas why?
Check if navigationController is pointing to nil. If it does, try
[self.view addSubview:self.pushViewController.view]
I had the same problem and found the above solution here:
UIViewController -viewDidLoad not being called
Unless you're doing something tricky, you should be calling alloc on the LoginViewController class rather than a variable. Also, if you've set up LoginViewController in Interface Builder (as opposed to programmatically), you'll need to load it from an NIB:
LoginViewController *lvc = [[[LoginViewController alloc] initWithNibName:nil bundle:nil] autorelease];
[self.navigationController pushViewController:lvc animated:NO];
Have a look at initWithNibName:bundle: in the docs.
Not entirely sure what you are trying to achieve but when you instantiate LoginViewContoller it should probably look like this
LoginViewController* lvc = [[LoginViewController alloc]init];
Judging by the nature of your naming for your view controller, is your LoginViewController the first view controller for your UINavigationController?
If that is what you're trying to do, you should instead initialise your navigation controller with the LoginViewController as the root controller instead of pushing it onto the navigation stack.
UINavigationController has a method to do this:
- (id)initWithRootViewController:(UIViewController *)rootViewController
EDIT:
Well, one way you can go about it is like this.
In your application delegate .h file, you should have declared a UINavigationController.
#interface MyAppDelegate : NSObject <UIApplicationDelegate>
{
UINavigationController *navController;
}
#property (nonatomic, retain) UINavigationController *navController;
#property (nonatomic, retain) IBOutlet UIWindow *window;
#end
In your App Delegate didFinishLaunching:withOption: you can create an instance of your LoginViewController there, and use that to init your UINavigation controller as the root view controller
#import "LoginViewController.h"
#implementation MyAppDelegate
#synthesize navController;
#synthesize window = _window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
LoginViewController *loginController = [[LoginViewController alloc] init];
navController = [[UINavigationController alloc] initWithRootViewController:loginController];
[loginController release];
[[self window] setRootViewController:navController];
[navController release];
[self.window makeKeyAndVisible];
return YES;
}
I probably have a typo here or there but that's one way I would go about doing it.
I'm trying to use a UINavigationController but I'm uncertain how. Up till now (for about a year), I've been using presentModalViewController and dismissModalViewController to present/dismiss view controllers.
So, this is what I did. My main view controller (the first one that shows on launch) is called MainViewController, and it extends UIViewController.
So I made this launch function in my app delegate:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
MainViewController *controller = [[MainViewController alloc] init];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:controller];
[self.window addSubview:navigationController.view];
[self.window makeKeyAndVisible];
return YES;
}
And in my MainViewController's viewDidLoad method:
- (void)viewDidLoad {
[super viewDidLoad];
self.title = #"Title";
self.navigationController.navigationBar.tintColor = [Constants barColor];
....more code...
}
But, in my MainViewController, I'd like to present another view controller called SecondViewController, which needs a UINavigationBar with a back arrow button. So do I make SecondViewController extend UIViewController and do the same thing by setting the title and backButton in the viewDidLoad method? And how do I present it? What should I do to accomplish this?
You'll need to set a root view controller up, it's easiest starting from the apple template.
Here's where the magic happens:
UIViewController *controller = [[UIViewController alloc] initWithNibName:#"MyNib" bundle:nil];
[self.navigationController pushViewController:controller animated:YES];
[controller release];
The nav controller does all the work for you (back buttons, titles, animations) - it keeps track!
My workflow is this:
Setup MutableArray in the viewDidLoad, add controllers to it, e.g:
NSMutableArray *array = [[NSMutableArray alloc] init];
MyCustomViewController *customView = [[MyCustomViewController alloc] initWithNibName:#"nib" bundle:#"nil"];
customView.title = #"Second Level";
[array addObject:customView];
self.controllers = array;
Then in your delegate:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSUInteger row = [indexPath row];
UIViewController *childControllerToBe = [controllers objectAtIndex:row];
[self.navigationController pushViewController:childControllerToBe animated:YES];
}
This, along with a lot more can be learnt by reading a decent beginner book such as Beginning iPhone Development
Also, apple docs are always good :)
UINavigationController is a subclass of UIViewController, but unlike UIViewController it’s not usually meant for you to subclass. This is because navigation controller itself is rarely customized beyond the visuals of the nav bar. An instance of UINavigationController can be created either in code or in an XIB file with relative ease.
Please visit "How to add UINavigationController Programmatically"
You should Push it onto the navigation stack.
This Lecture by Stanford's iPhone Course will teach you a lot about Navigation Bars. (It's a quick read)
Basically at the heart of it you need this code:
[self.navigationController pushViewController:SecondView];
You can use PopViewController to go back programmatically, but the Back Button is automatically created.
Here's some source code from the Lecture. It covers exactly what you are having issues with.
I'm using two UIViewController in Application Delegate and navigating to UIViewController using presentmodalviewcontroller. But Problem is that presentmodalviewcontroller works for first time UIViewController and when i want to navigate to second UIViewController using presentmodalviewcontroller then its showing first UIViewController.
The following is the code:-
-(void)removeTabBar:(NSString *)str
{
HelpViewController *hvc =[[HelpViewController alloc] initWithNibName:#"HelpViewController" bundle:[NSBundle mainBundle]];
VideoPlaylistViewController *vpvc =[[VideoPlaylistViewController alloc] initWithNibName:#"VideoPlaylistViewController" bundle:[NSBundle mainBundle]];
if ([str isEqualToString:#"Help"])
{
[tabBarController.view removeFromSuperview];
[vpvc dismissModalViewControllerAnimated:YES];
[viewController presentModalViewController:hvc animated:YES];
[hvc release];
}
if ([str isEqualToString:#"VideoPlaylist"])
{
[hvc dismissModalViewControllerAnimated:YES];
[viewController presentModalViewController:vpvc animated:YES];
[vpvc release];
}
}
Can Somebody help me in solving the problem?
You're making a new hvc and vpvc each time you run this function.
The first time through, I assume you call removeTabBar:#"Help", it makes a hvc and vpvc and then shows the correct one.
The second time you call it removeTabBar:#"VideoPlayList", you are making a new hvc and vpvc. This means that when you call hvc dismissModalViewController:YES]; you're not removing the one you added before, you're removing the new one that you just made which isn't being displayed at all!
To solve this you need to make your two controllers as properties in your app delegate and create them in the applicationDidFinishLaunching method.
Add these into your app delegate's .h file:
#class MyAppDelegate {
HelpViewController *hvc;
VideoPlaylistViewController *vpvc;
}
#property (nonatomic, retain) HelpViewController *hvc;
#property (nonatomic, retain) VideoPlaylistViewController *vpvc;
#end
and in your app delegate's .m file :
- (void)applicationDidFinishLaunching:(UIApplication *)application {
...
self.hvc = [[[HelpViewController alloc] initWithNibName:#"HelpViewController" bundle:nil] autorelease];
self.vpvc = [[[VideoPlaylistViewController alloc] initWithNibName:#"VideoPlaylistViewController" bundle:nil] autorelease];
...
}
and remove the first two lines in removeTabBar
Hey everyone, I am new to iPhone development and I'm not understanding the whole UINavigationController and UITabBarController idea. Is one a substitute for the other - how do apps such as Tweetie combine both?
I'd like to have my app have a persistent Tab Bar # the bottom (which seems to be working), but also a Navigation bar at the top which can push/pop views onto the screen without removing the tab bar.
How can I accomplish this?
What should the hierarchy look like in IB as far as my MainWindow.xib with regards to all of these controllers?
What is best practice here?
Thanks very much,
Just wrap the view controller inside the UINavigationController and Place the UINavigationController inside the UITabBar.
This will work fine for you…
Example:
NSMutableArray *tabBarViewControllers = [[NSMutableArray alloc] initWithCapacity:2];
tabBarController = [[UITabBarController alloc] init];
[tabBarController setDelegate:self];
UINavigationController *navigationController = nil;
navigationController = [[UINavigationController alloc] initWithRootViewController:<Your View controller1>];
[tabBarViewControllers addObject:navigationController];
[navigationController release];
navigationController = nil;
navigationController = [[UINavigationController alloc] initWithRootViewController:<Your View controller2>];
[tabBarViewControllers addObject:navigationController];
[navigationController release];
navigationController = nil;
tabBarController = tabBarViewControllers;
[tabBarViewControllers release];
tabBarViewControllers = nil;
Use the wizard for a Tab Bar Application, and set it up as normal. In any tab where you want to add a navigation controller, create it in the XIB using the library. My XIB has:
- File's Owner DescriptiveNameNavViewController
- First Responder
- View UIVIew
- Navigation Controller UINavigationController
- Navigation Bar UINavigationBar
Note that there isn't anything in the view. See viewDidLoad below for where the UINavigationController gets attached to the UIView.
In the header file for the Tab's ViewController (which I've here called DescriptiveNameNavViewController -- there isn't a particular standard for this, but I use [Something]NavViewController to remind me that this ViewController contains a navigation controller with the navigation stack. This is the controller name that I set in the MainWindow.xib that the wizard generates) Set up a UINavigationController * IBOutlet that has the navigation controller in the XIB attached to it:
#interface DescriptiveNameNavViewController : UIViewController {
UINavigationController *navigationController;
}
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#end
In the controller for the DescriptiveNameNavViewController , do something like this:
- (void)viewDidLoad {
[super viewDidLoad];
[[self view] addSubview:[navigationController view]];
DescriptiveNameController *aController = [[[DescriptiveNameController alloc ] initWithNibName:#"DescriptiveNameController" bundle:nil ] autorelease];
aController.title = #"Descriptive Title";
//
// app stuff goes here.
//
[self.navigationController pushViewController:aController animated:YES];
[self.navigationController setDelegate:self];
}
Setting the delegate in the DescriptiveNameNavViewController is super-important, because otherwise you won't get the methods called that you expect in DescriptiveNameViewController instances and anything else you push into the navigation controller's stack.
In DescriptiveNameNavViewController, implement the UINavigationControllerDelegate methods like this:
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
if ([viewController respondsToSelector:#selector(viewDidAppear:)]) {
[viewController viewDidAppear:animated];
}
}
And that will cause messages to get propagated to controllers inside the UINavigationController like you expect. It seems like many problems that people encounter are because the viewDidAppear: or other methods aren't getting called on the ViewControllers pushed into the NavigationController.
Anyway, let me know if more detail would help.