I have an universal application that had all views in the same file MainWindow.xib. Today I decided to separate these views into their respective xib files (to have MainMenuController.h, MainMenuController.m and MainMenuController.xib for example). Now I can't receive and IBActions. Here is what I did step by step:
I created a new .xib file named MainMenuController.xib and set it's File's Owner to the already existing MainMenuController class.
I copied the view corresponding to the MainMenuController from the MainWindow.xib file and pasted it into the newly created MainMenuController.xib. I set the File's Owner's view to be the newly pasted view (connected in IB).
In the info.plist, I removed the entries for the "Main xib file base name", so the app doesn't open with MainWindow.xib automatically.
I modified the app delegate to create the window programatically and add the MainMenuController to it with this code:
window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
mainMenuController = [[MainMenuController alloc] init];
self.window.rootViewController = mainMenuController;
[self.window makeKeyAndVisible];
[mainMenuController release];
"mainMenuController" and "window" are instance variables and also declared as properties.
I have only one AppDelegate class and main.m contains:
int main(int argc, char *argv[])
{
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}}
Now when the application opens, I see the MainMenuController's view come up. At this point I began to wire the IBOutlets and IBActions in the pasted view in the new xib file. Although I see the IBOutlets in the File's Owner and connect them properly, the function for the IBAction is never called when I press the button.
Possible errors that came to my mind:
(1) application window not properly set, it doesn't pass events,
(2) something is stuck or lost while copying the view, still pointing to the old owner
(3) something wrong stuck in xcode project
What do you think the problem could be? Is it one of the above? How can I solve this? Any help is appreciated.
Thanks in advance.
Your creation of the main view controller:
mainMenuController = [[MainMenuController alloc] init];
makes no reference to the XIB. So you're doing a purely programmatic creation with no reference to whatever may or may not be in the XIB. Hence your view controller appears to work but none of the outlets or actions are wired up. You may be making reference elsewhere, but I guess not appropriately.
Probably you want:
mainMenuController = [[MainMenuController alloc]
initWithNibName:#"MainMenuController" bundle:nil];
That'll explicitly use whatever is in the XIB to create the controller.
Related
I'm a beginner leearning Xcode, and I created a simple single view application for a pretty useless card game (it's not even really a game).
What I want to know is is it possible to import my single view application into an application with storyboards without having to make a new project and retyping all of the code and connections?
Or is it possible to make a multiview application without storyboards, that I could continue off in the same project?
If so, can anyone direct me to a resource to do so? Thanks.
You can make a multiview application without using Storyboard.
Make a new UIViewController with a nib
Apple's example of presented a view controller programmatically
- (void)add:(id)sender {
// Create the root view controller for the navigation controller
// The new view controller configures a Cancel and Done button for the
// navigation bar.
RecipeAddViewController *addController = [[RecipeAddViewController alloc]
init];
// Configure the RecipeAddViewController. In this case, it reports any
// changes to a custom delegate object.
addController.delegate = self;
// Create the navigation controller and present it.
UINavigationController *navigationController = [[UINavigationController alloc]
initWithRootViewController:addController];
[self presentViewController:navigationController animated:YES completion: nil];
}
If you are using an nib though you would want to allocated as followed:
RecipeAddViewController *addController = [[RecipeAddViewController alloc]
initWithNibName:#"yourNibName" bundle: nil];
http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/ModalViewControllers/ModalViewControllers.html#//apple_ref/doc/uid/TP40007457-CH111-SW1
You can easily just copy your source and header files of choice to whichever project you like (beware of enabled/disabled ARC, though). Also, you can mix storyboards and nib files as you wish. Here's a little documentation on nibs that you might find interesting. Basically, you can init a UIViewController with it's nib file like this:
MyViewController *myViewController = [[MyViewController alloc] initWithNibName:#"MyViewController" bundle:nil];
Yes, you can go with #Alex answer.
And you can also add "Storyboard" in your project.
Steps to add storyboard are as follows:-
1. Add new file => Click on "User Interface" tab on left side => Select storyboard => Choose Device type => and create. A blank storyboard file has been created.
2. Now, drag-drop a UIViewController from list of objects(right side) and reference it with your view controller class.
In the same way, you can add other views using storyboard and create multi-view app.
I tried looking for a similar problem but I could not find a similar question.
I am loading a UINavigationController in a UIView which is not (as in most examples) the MainWindow.
I created one new .xib called DocumentsViewController which is subclass of UIView (it has the related .m and .h files). And I created a DocumentsRootViewController.xib, which is a subclass of UITableViewController, which is supposed to be the UINavigationController's RootViewController.
I moved to DocumentsViewController and added a UINavigationController object in Interface Builder. Then I went to code, and added it as in IBOutlet, and connected it to the object.
In the ViewDidLoad, I execute the following lines:
DocumentsRootViewController *rootViewController = [[[DocumentsRootViewController alloc] init] autorelease];
rootViewController.title = #"Documents";
[navigationControllerDocuments initWithRootViewController:rootViewController];
[self.view addSubview:navigationControllerDocuments.view];
It shows the table as intended, but it shows a "Back" button to the "Root View Controller" (as in picture below).
Why? Shouldn't it already know that the rootviewcontroller has been set?
Thank you in advance to the ones that clarify this doubt
Giovanni
When you add the UINavigationController via the Nib it actually creates an instance of a UINavigationController inside the nib file with a default RootViewController set (of type UIViewController) and with a default title of RootViewController.
When you load the nib, this object is being created as part of loading the nib (i.e when you initialise DocumentsViewController) - so the navigationControllerDocuments outlet is already initialised as a UINavigationController with the default ViewController already set on it.
What I think is happening is when you call 'initWithRootViewController' - you are calling this on an already initialised object - so it is running the initialisation code again - pushing the second view controller (the DocumentRootViewController) onto the stack, but the default one that was created in the nib is already there.
What you should probably do is forget about creating one in the nib and initialise the whole thing programatically.
i.e. where you do:
[navigationControllerDocuments initWithRootViewController:rootViewController];
I suggest that you do an alloc and init instead:
[[navigationControllerDocuments alloc] initWithRootViewController:rootViewController];
Since you are doing this you really don't need to have the navigation controller added to the nib so if this works you should remove it from the nib since you are replacing it with this one in code.
I am trying to programmatically create a view controller. I would like to know when I should create the view controller using a NIB file, and when I should create it programmatically.
I would also like step-by-step instructions to create the view controller without a NIB file.
Use the IB when ever you like to. Use code in the remaining cases.
Here is how you can get rid of the IB in the creation of the AppDelegate.
Remove the entry "Main nib file base name" in the Info.plist
Change int retVal = UIApplicationMain(argc, argv, nil, nil); in main.m to int retVal = UIApplicationMain(argc, argv, nil, #"MyCoolApplicationAppDelegate"); where "MyCoolApplication" is the name of your app.
Add in "MyCoolApplicationAppDelegate" in applicationDidFinishLaunching:application the following code:
window = [[UIWindow alloc] initWithFrame: [[UIScreen mainScreen] bounds]];
To create a view controller without a nib do:
MyCoolViewController *myCoolViewController = [[MyCoolViewController alloc] init];
and in the load view of MyCoolViewController you can add initialize the corresponding view and attach it to the your view controller via:
[self setView: MyCoolView];
Personally, I like to use IB for ViewControllers that contain mostly static views. When a ViewController has a lot of views that I need to create dynamically, or animate I prefer to create the ViewController with code.
See the View Controller Programming Guide for iOS: Understanding the View Management Cycle.
That should tell you when and why the methods are called and in what order.
I am trying to figure out the relationship between the appdelegate, RootViewControoler, and UIApplication. Here is what I kinda have figured out so far:
When starting your application up, main.m gets loaded.
From here, your MainWindow.xib gets loaded.
In your MainWindow.xib, your File's Owner is of type UIApplication.
You set your UIApplication's delegate to your AppDelegate.
In your AppDelegate's source code, you can set your RootViewController to be the first view shown.
Is this right? What prompts AppDelegate to initially run it's
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { }
method?
When an Objective-C application starts, it starts by running the function named main(). It doesn't have to be in the file "main.m" but that's how the Xcode wizard sets things up.
Inside the wizard-produced main() function, there is this line:
int retVal = UIApplicationMain(argc, argv, nil, nil);
That is what starts the "UIKit" framework that makes up the entire application. Inside UIApplicationMain, an object of type UIApplication is created. And part of what UIApplication does when the application starts is call the applicationDidFinishLaunchingWithOptions method on the delegate member of the UIApplication class. This delegate is set up in the MainWindow.xib file to be an instance of your ProjectAppDelegate class, a subclass of NSObject that conforms to the UIApplicationDelegate protocol.
What prompts AppDelegate to initially
run it's ...
Because in your MainWindow.xib file you have connected (well the project wizard did the connection actually) the File's Owner (which is the UIApplication object)'s "delegate" outlet to the UIApplicationDelegate object in the the .xib file, and the class of the UIApplicationDelegate is set to your app's UIApplicationDelegate subclass.
And there's nothing magic about "MainWindow.xib", it could be called "Foo.xib", what's important is that the property in your Info.plist file called "Main nib file base name" is "MainWindow". Trying renaming MainWindow.xib to Foo.xib and changing the "Main nib file base name" in your Info.plist to "Foo" and you'll see it still works.
EDIT: more about RootController
Again, there's nothing magic about the so-called "RootController". This is just the name of the UIViewController subclass created for you by the Xcode new project wizard.
The wizard places code in the project for two classes: ProjectAppDelegate and ProjectViewController. The ProjectAppDelegate class contains two outlet members:
IBOutlet UIWindow *window;
IBOutlet ProjectViewController *viewController;
in the MainWindow.xib file, instances of both UIWindow and ProjectViewController are placed, and hooked up to the above outlets in ProjectAppDelegate.
What gets your stuff up on the screen is this code in your ProjectAppDelegate class:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
// Add the view controller's view to the window and display.
[self.window addSubview:viewController.view];
[self.window makeKeyAndVisible];
return YES;
}
Again, nothing really magic about this: the project wizard created code that adds your "root" ViewController's view to the window's view, and makes the window visible. Your "root" view controller was create in the .xib file, and hooked up to the ProjectAppDelegate outlet.
It is very instructive to try to create an application entirely by yourself without using any of the files from the wizard. You'll learn a lot about how .xib files work and how they relate to code objects.
The starting point of iOS apps is always the main() function (thanks #bogatyr) which usually contains code similar to,
int main(int argc, char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, nil);
[pool release];
return retVal;
}
The last two parameters of UIApplicationMain are important and specify the principal class name, and the application delegate. If they are nil, then Info.plist will be looked up for the main window xib (usually MainWindow.xib).
// If nil is specified for principalClassName, the value for NSPrincipalClass
// from the Info.plist is used. If there is no NSPrincipalClass key specified, the
// UIApplication class is used. The delegate class will be instantiated
// using init.
.. UIApplicationMain(int argc, char *argv[], NSString *principalClassName, NSString *delegateClassName);
It is not necessary to set the File Owner through xib, and they can be specified directly in this UIApplicationMain function.
principalClassName can be the string UIApplication or a subclass of UIApplication. Similarly delegateClassName can be directly specified in this method. The delegate class is instantiated using init as the docs say. Suppose we specify our delegate class - MyAppDelegate as a string,
UIApplicationMain(int argc, char *argv[], nil, #"MyAppDelegate");
First an instance of UIApplication is instantiated, which will then create the delegate class from this string using NSClassFromString I suppose.
Once delegateObject has been instantiated, and application is ready, this delegateObject will be informed using the delegate method, didFinishLaunchingWithOptions.
Class delegateClass = NSClassFromString(#"MyAppDelegate");
id <UIApplicationDelegate> delegateObject = [[delegateClass alloc] init];
// load whatever else is needed, then launch the app
// once everything is done, call the delegate object to
// notify app is launched
[delegateObject application:self didFinishLaunchingWithOptions:...];
This is how UIApplication would handle it programmatically, if no nib is used. Using a nib in the middle is not much different.
Since your AppDelegate is a delegate of UIApplication - it listens to all notifications that UIApplication class posts during it's lifecycle. didFinishLaunching notification is one of them and it causes your AppDelegate to call aforementioned method.
For Universal — iPhone + iPad — apps you can specify that different NIBs load on each platform, either in the target Info panel or by adding NSMainNibFile~ipad and NSMainNibFile~iphone keys to your Info.plist. Alternatively, you can add a MainWindow~ipad.xib NIB to your target, it will be loaded on the iPad instead of MainWindow.xib, based on the NSMainNibFile key in Info.plist.
If you need more control and customization for a Universal app you can load the starting NIB manually. The "Universal" project template has the boilerplate for this method, so the quickest way to get started using this technique is to just create a new iOS project with the Universal profile.
In the above examples the Main NIB File is set in Info.plist (target settings) so that you will already have a NIB loaded when your application delegate is invoked. Usually in this setup a MyAppDelegate object will also be archived in the NIB (with some IBOutlets) and the NIB's File's Owner will be set to UIApplication.
For a universal project to be able to accommodate two alternative layouts, the Main NIB File key is left out of Info.plist. Then it instantiates the application delegate object programmatically in UIApplicationMain:
#import "MYAppDelegate.h"
int main(int argc, char *argv[])
{
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([MYAppDelegate class]));
}
}
Then check your environment and settings and load the appropriate NIB in application:DidFinishLaunchingWithOptions:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
_window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
_viewController = [[[MYViewController alloc] initWithNibName:#"MYViewController_iPhone" bundle:nil] autorelease];
} else {
_viewController = [[[MYViewController alloc] initWithNibName:#"MYViewController_iPad" bundle:nil] autorelease];
}
_window.rootViewController = _viewController;
[_window makeKeyAndVisible];
return YES;
}
- (void)dealloc {
[_window release];
[_viewController release];
[super dealloc];
}
The new step is to create a root MYViewController manually, loading the appropriate NIB. In this setup the File's Owner is your shiny new MYViewController rather than UIApplication. If you want, MYViewController can adopt much of what you may have been using your application delegate for - which is often to encapsulate the core model class of the app, act as a data source and delegate for the views and other things in the NIB.
So you're expected to have some root UIView in the NIB, and it should be hooked up to the view outlet of the File's Owner (MYViewController).
Note that MYViewController's NIB isn't actually loaded until the first time the MYViewController.view property is accessed. Only then will [MyViewController viewDidLoad] be called! The most likely time for this to occur is when you add it to the root window.
In the template code shown above the root UIWindow is instantiated by the app delegate, but there's no reason you couldn't include it in your NIB instead. If you choose to do this, be careful. If you set the rootViewController of the window in the NIB to the File's owner in that case, it will cause the controller's view to be added to the window when the window is activated. Be careful constructing that first NIB in any case.
The app delegate doesn't necessarily need to have a reference to your root UIWindow if you want MYViewController to manage it, but it may be cleaner overall to keep the root window out of your NIBs and manage it in the app delegate.
Outside of that (!) there's not much different from the single-platform approach.
MainWindow.xib is defined in your info.plist as the Main nib file base name. In your MainWindow.xib, you define the first controller that you want to load, in your case, RootViewController.
didFinishLaunchingWithOptions: is part of the UIApplicationDelegate protocol. This method (in iOS4.0+) is always known to be the first to be called when launching an application.
I recently started a project, using Apple's Utility Application example project. In the example project, there's an info button that shows an instance of FlipSideView. If you know the Weather.app, you know what the button acts like.
I then changed the MainWindow.xib to contain a scrollview in the middle of the window and a page-control view at the bottom of the window (again, like the Weather.app). The scrollview gets filled with instances of MainView. When I then clicked the info button, the FlipSideView would show, but only in the area that was previously filled by the MainView instance – this means that the page-control view on the bottom of the page still showed when the FlipSideView instance got loaded.
So, I thought that I would simply add a UIViewController for the top-most window, which is the one declared inside the AppDelegate created along side with the project. So, I created a subclass of UIViewController, put an instance of it inside MainWindow.xib and connected it's view outlet to the UIWindow declared as window inside the app delegate. I also changed the button's action, so that it know sends a message to the MainWindowController instance. The message does get sent (I checked with NSLog() statements), but the FlipSideView doesn't get shown. Here's the relevant (?) code:
FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:#"FlipsideView" bundle:nil];
controller.delegate = self;
controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:controller animated:YES];
[controller release];
Why's this not working from inside of MainWindowController, but the exact same code is working from inside of MainViewController? I've uploaded the entire project here for you to be able to see the whole thing.
Thanks for help!
-- Ry
EDIT: I think it might be related to me attaching the UIViewController's view outlet to an UIWindow instance. I now connect it to a UIView, and it's working perfectly well.
For the record, the answer has been added in the question. Ryyst said:
I think it might be related to me
attaching the UIViewController's view
outlet to an UIWindow instance. I now
connect it to a UIView, and it's
working perfectly well.