I have a really strange delegate behavior in iOS. I'm setting a custom delegate in a subclassed UIViewController like this:
- (void)viewDidLoad
{
[super viewDidLoad];
self.baseNavigationBar = [[BaseNavigationBar alloc] initWithNibName:nil bundle:nil];
self.baseNavigationBar.delegate = self;
self.baseNavigationBar.navigationController = self.navigationController;
[self.navigationController.navigationBar addSubview:self.baseNavigationBar];
}
The initWithNibName can use nil, when using the default nib, because internally it will check fora nil in the nibName.
if (!nibNameOrNil) {
nibNameOrNil = NSStringFromClass([self class]);
}
The delegate declaration from the baseNavigationBar object looks the following:
#property (nonatomic, retain) id<BaseNavigationBarDelegate> delegate;
/*same thing with assign, which I you should use*/
/*and in the .m of course #synthesize*/
And now 2 screenshots from the running application.
The first one show's the debugger values from the BaseListViewController, which is a subclass of BaseCoreViewController, which is a subclass of UIViewController.
The screenshot is taken, when the viewDidLoad method is called.
The second one show's the values from the BaseNavigationBar, which is a UIView subclass.
The screenshot is taken at a time, when the user clicks the "next" button
- (IBAction)nextAction:(id)sender {
if (self.delegate) {
[self.delegate navigationBarDidClickNextButton:self];
}
}
So why is this a problem? By clicking a button in the BaseNavigationBar my delegate is always nil, so the program is stuck. But when looking at the values from the BaseCoreViewController at the same time the delegate is not nil. Very strange.
Edit
The BaseNavigationBar is loaded from a nib file using the UINib loadNibNamed:owner:options: function.
Edit 2
So that's pretty much all of the code.
Edit 3
Finally we got the source of the error in the last pieces of the code... setting self = something totally not allowed...
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (!nibNameOrNil) {
nibNameOrNil = NSStringFromClass([self class]);
}
if (!nibBundleOrNil) {
nibBundleOrNil = [NSBundle mainBundle];
}
NSArray *topLevelObjects = [nibBundleOrNil loadNibNamed:nibNameOrNil owner:self options:nil];
/*Here is the bad part*/
self = [topLevelObjects objectAtIndex:0];
state = BaseNavigationBarButtonStateNext;
if (self) {
self.title = #"";
}
return self;
}
Solved using a Class method instead of defining a custom init.
If you are using nib file, you should declare the nib class while initialising your class object.
You have initialised initWithNibName:nil
self.baseNavigationBar = [[BaseNavigationBar alloc] initWithNibName:nil bundle:nil];
but it should be like initWithNibName:#"BaseNavigationBar"
self.baseNavigationBar = [[BaseNavigationBar alloc] initWithNibName:#"BaseNavigationBar" bundle:nil];
Not sure what the problem is. Require some more code to analyze the problem. But what I can see is address of BaseNavigationBar in both the screen shots is different. It means the BaseNavigationBar object present in the controller is not the one which got the nextAction event as in second screen shot.
Related
I have a code that load the custom view from a nib file but there is a problem with the variable of that custom view.
- (id)initWithFrame:(CGRect)frame
{ self = [super initWithFrame:frame];
if (self) {
// Initialization code
HomeMainView* views = (HomeMainView*)[[[NSBundle mainBundle] loadNibNamed:#"HomeMainView" owner:self options:nil] objectAtIndex:0];
[self release];
NSArray* permission = [NSArray arrayWithObjects:#"user_photos",#"publish_stream", nil];
FBLoginView* fbLogin = [[[FBLoginView alloc] initWithPublishPermissions:permission defaultAudience:FBSessionDefaultAudienceFriends] autorelease];
[views.FBLogin addSubview:fbLogin];
[views.homeButton setTitle:#"asdf" forState:UIControlStateNormal];
self = views;
}
return self;
}
I am trying to add the fbLogin to the views object generated by the Nib file. The problem is the views.FBLogin generate the errors saying unrecognized selectors.
Does anyone know what is wrong here?
I had the same problem but it was because I needed to add this to my app delegate didFinishLaunchingWithOptions :
[FBLoginView class]
Without this the UIView was a UIView not an FBLoginView, hence the unrecognized selector.
Make sure that you have set the custom class in interface builder for the view. Select the view and press cmd+option+3 and set the custom class.
I have a UIViewController called LaunchController that is launched in my iPhone app when the app first opens:
#interface LaunchController : UIViewController<UINavigationControllerDelegate, UIImagePickerControllerDelegate>
Then, when a button is clicked, I push another view controller:
MainController *c = [[MainController alloc] initWithImage:image];
[self presentModalViewController:c animated:NO];
MainController has the following constructor, which I use:
- (id)initWithImage:(UIImage *)img
{
self = [super init];
if (self) {
image = img;
NSLog(#"inited the image");
}
return self;
}
and then it has a viewDidLoad method as follows:
- (void)viewDidLoad
{
NSLog(#"calling view did load");
[super viewDidLoad];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[self.view addSubview:imageView];
NSLog(#"displaying main controller");
}
When the program runs, I see that the constructor for MainController is called (due to the output of NSLog), however viewDidLoad never gets called, even though I am calling presentModalViewController. Why is this? Why isn't viewDidLoad being called?
I think it is something as followings. When you need the property of view inside UIViewController, it will be loaded with lazy manner.
- (UIView *)view
{
if (_view == nil) {
[self loadView]; //< or, the view is loaded from xib, or something else.
[self viewDidLoad];
}
return _view;
}
After the view initialized, it will call viewDidLoad to inform the UIViewController.
You aren't loading your view controller from a xib file, and from comments you don't have anything in loadView (which is where you would create your view controller's view if you were not using a xib file).
Therefore, your view isn't being loaded, so viewDidLoad is never called.
Typically you would use initWithNibName: to initialise a new view controller, and then set the image after it (so expose the image as a property).
viewDidLoad will be called as soon as your controller's view property is accessed, that is when you display it for the first time or request it (e.g. have some code that calls c.view.
The reason viewDidLoad is not being called is because you aren't loading a view.
In your init method:
self = [super init];
means that you are just creating a naked view from scratch. not loading one from a nib.
try this instead:
self = [super initWithNibName:nil bundle:nil];
If you have a xib or nib file with the same name as the view controller class it should find if. Otherwise, you can just give a nibName that works.
UPDATE:
If you are not using nib files, then the appropriate method is NOT viewDidLoad. You have to implement loadView instead of viewDidLoad.
In your specific case, just put everything that is currently in viewDidLoad into loadView.
I have one view who calculates location and reverser geocode to get the zip code. Then it calls another view where I want to display weather results based on that zip code.
In the first view controller I do this once user clicks on the button to turn the page:
- (IBAction) showMyWeather : (id)sender {
WeatherApp *weather = [[WeatherApp alloc] initWithNibName:nil bundle:nil];
weather.zipcode = placemarkZip; //this one seems not to be doing the job
weather.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:weather animated:YES];
}
And at the WeatherApp I would like to read now zipcode, which is declared in this view controller .h:
#interface WeatherApp : UIViewController{
IBOutlet UIButton *done;
MKPlacemark *zipcode;
}
#property (nonatomic, retain) MKPlacemark *zipcode;
How can I use this code to transfer this zipcode to the WeatherApp? Thanks!
Yes, this is a fine way to pass information into your new object.
Alternatively, you could create a custom initializer for WeatherApp like
- (id)initWithZipCode:(NSString *)zip;
and then in the implementation file, it could be like this:
- (id)initWithZipCode:(NSString *)zip
{
self = [super init];
[self setZipcode:zip];
return self;
}
Finally, you could instantiate the class like so:
- (IBAction)showMyWeather:(id)sender
{
WeatherApp *weather = [[WeatherApp alloc] initWithZipCode:placemarkZip];
[weather setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];
[self presentModalViewController:weather animated:YES];
[weather release]; // No longer needed with ARC... just sayin'
}
Finally, if you're going to continue to pass in information as you do above, I'd question why you're using initWithNibName:bundle:. If you're just going to pass nil to both, why not just use [[WeatherApp alloc] init]?
In the app im creating there are many pages that look mostly the same with some part which is different. To handle this kind of situation i created a container controller that contains a subview. I want this subview to be filled by the contents of another controller (and its associated nib) which i will created dynamically as needed based on context.
I have the following method somewhere
- (void) someAction {
UIViewController* contentController = [[MyContentController alloc] init];
UIViewController* containerController = [[MyContainerController alloc] initWithContentController:contentController];
[navigationController pushViewController:pageController animated:YES];
[contentController release];
[containerController release];
}
In MyContainerController.m i retain the controller in a property
- (id)initWithContentController:(UIViewController *)aContentController {
if ((self = [super initWithNibName:#"MyContainerController" bundle:nil])) {
contentController = aContentController;
}
return self;
}
Later in viewDidLoad i do the following
- (void)viewDidLoad {
[super viewDidLoad];
[contentViewContainer addSubview:contentController.view];
}
contentViewContainer is the view that's supposed to hold the page specific info.
Unfortunatly this fails with EXC_BAD_ACCESS.
The funny thing is that if i alloc and init the content controller from within viewDidLoad everything works. It seems that i cant pass a contoller i allocated from another place.
Can anyone assist.
Since you are releasing contentController in the actionMethod
you have to retain contentController in you init method
- (id)initWithContentController:(UIViewController *)aContentController {
if ((self = [super initWithNibName:#"MyContainerController" bundle:nil])) {
contentController = [aContentController retain];
}
return self;
}
But, why do you need this? Controllers are supposed to control views and no other controllers. If you think you really need that then you want to use UINavigationController or UITabBarController maybe.
You can also load views without a controller (see here)
I personally think that having UIViewControllers inside of simple UIViewController is not a preferable approach
Hope it helps
I have a uiviewcontroller with two properties: trackName and playerObject. PlayerObject also has a trackName property. I call this uiviewcontroller from my main uiviewController with this code:
SecondaryViewController *nextViewController = [[SecondaryViewController alloc] initWithNibName:#"SecondaryViewController" bundle:nil];
NSString *trackName = #"a track";
nextViewController.trackName = trackName;
[self.navigationController pushViewController:nextViewController animated:YES];
[nextViewController release];
In SecondaryViewController I override the initwithnibname method to set the trackName of the playerObject. I do this with this code:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
playerObject.trackName = trackName;
}
playerObject.trackName = trackName;
return self;
}
Finally my playerObject has all of the view data the SecondaryViewController will need. It looks like:
- (void)awakeFromNib{
NSString *s = trackName;
//more code relevant to the the view controller
}
When I debug, the trackName string in the playerObject is nil. I assume I'm doing something wrong. How can I have this value populated with the trackName I originally passed in the main uiview controller?
It seems like when you are initing the viewController the playerObject variable has not yet been set, could this be possible?
This can sometimes happen when you override initWithNibName:bundle:.
Instead use viewDidLoad to do setup. Apple guarantees all required setup is performed before this method is called (not the case with initWithNibName:bundle:).