I have 2 view controllers in a tab bar controller. My 2nd Nav Controller wants to set a badge value.
This controller is not loaded when the app starts, so the badge does not show. If I go over to that tab, the badge is properly updated.
this snippet runs when the tab's View Controller loads/reloads/updates/etc...
[self.navigationController.tabBarItem setBadgeValue:[NSString stringWithFormat:#"%u",[self.photos count]]];
Is the correct way to do this: Override the Nav Controller with a custom class and put the badge value in at that level? It seems like that is where I should put this info, but I haven't found a definite answer.
When the TabBarController is loaded, all of it's contained initial viewControllers are initialised. But their views are not loaded until you navigate to the respective tab item. So you can't execute code at this point in any of the view-loading methods (viewDidLoad etc). However you can execute code by overriding one of the initialisation methods.
If using storyboards the process of unarchiving the viewController triggers this method when the NIB has loaded:
- (void) awakeFromNib
{
}
If not using Storyboards, this initialiser is called prior to NIB loading:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
In either case you can override these methods to execute some code...
- (void) awakeFromNib
[super awakeFromNib];
[self.navigationController.tabBarItem
setBadgeValue:[NSString stringWithFormat:#"badgeValue"]]];
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
[self.navigationController.tabBarItem
setBadgeValue:[NSString stringWithFormat:#"badgeValue"]]];
}
return self;
}
However you will need to take care where you are getting your data from. At this point self.photos may be uninitialised for example. If the data for this is coming out of userdefaults, you should be able to read those in here and set your badge accordingly.
Related
I am trying to debug why my override of dealloc is not getting called on one of my view controllers.
I have a view controller that is setup by storyboarding. I have override all 3 init methods:
-(id) initWithCoder:(NSCoder *)aDecoder {
NSLog(#"TestViewController init with coder");
return [super initWithCoder:aDecoder];
}
-(id) initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
NSLog(#"TestViewController init with nib name");
return [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
}
- (id) init {
NSLog(#"TestViewController init");
return [super init];
}
When I navigate to the said view in my app I see that 'initWithCoder' is called as expected. This is the only init method that I see called at all. It is called once when I navigate to my view.
However when I navigate away from my view controller dealloc does not get called. viewDidDisappear does get called. In view didDisappear I log the reference count:
-(void) viewDidDisappear:(BOOL)animated {
NSLog(#"TestViewController Retain count is %ld", CFGetRetainCount((__bridge CFTypeRef) self));
[super viewDidDisappear:animated];
}
Reference count is 5.
I also log the reference count in viewDidLoad and it is 8.
So it jumps from 5 to 8, then back to 5.
I only see the init method called once. I have no idea where to even start looking....
Do you have an instance variable pointing to your viewController object? If you still have a pointer it will not decrement the retain count even if the view is not on the screen.
The unusual retain counts are normal. The only count that matters is 0. If it is 0 it will be deallocated. There is no guarantee that one pointer means there will be a retain count of 1.
I am new to iOS programming. I have created ViewController with MKMapView element, and I wanted to set delegate [mapView setDelegate:self]
First I done it in method initWithNibName:bundle: like:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
[[self map] setDelegate:self]];
UITabBarItem *item = [[UITabBarItem alloc] init];
[item setTitle:#"Map"];
[self setTabBarItem:item];
}
return self;
}
In this case MKMapView did not send me any messages, but when I placed setting delegate message to viewDidLoad method, it worked fine.
Could someone explain me why it was not working when setting delegate message was in initWithNibName:bundle?
Views do not get loaded in initWithNibName, it just initializes your viewcontroller class and load the xib file which contains your view details.
When viewcontroller calls viewDidLoad, you will have all your view objects allocated and initialized.
In your case, when you setDelegate in initWithNibname, you are calling it on a nil value, so nothing get set, but in viewDidLoad mapView is allocated and initialized, so it works fine.
For a deeper insight refer:
http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/ViewLoadingandUnloading/ViewLoadingandUnloading.html
Beautiful explanation here: What is the process of a UIViewController birth (which method follows which)?
Looking to understand the iOS UIViewController lifecycle
http://thejoeconwayblog.wordpress.com/2012/10/04/view-controller-lifecycle-in-ios-6/
This line is your problem:
[self map]
In initWithNibName the map is not yet initialized and it returns nil.
In viewDidLoad the map is already initialized.
I notice "-(id) init" in ViewController is not executed when using storyboard. is there any other method that could replace init, or is there is away to force firing init.
try to use
- (id)initWithCoder:(NSCoder*)aDecoder
{
if(self = [super initWithCoder:aDecoder])
{
// Do something
}
return self;
}
- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle is called instead.
As the comment above indicates, you need to decide if there might be a more appropriate method to override. Keep in mind that the view has not yet been loaded in the initWithNibName method, so don't try to change anything there yet.
I have a view controller that initializes two other view controllers. The view for one controller wasn't showing, and I tracked the problem to the instance being nil when it's added to the superview.
Here is the code. viewDidLoad is being called before the favoritesTableVC is initialized. I can see this by placing breakpoints in the initialization methods of the resultsTableVC and favoritesTableVC view controllers.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
resultsTableVC = [[[ResultsTableVC alloc] initWithController:self andTableView:nil] retain];
favoritesTableVC = [[[FavoritesTableVC alloc] initWithFrame:CGRectMake(0, 10, self.view.frame.size.width, defaultFavoritesTableHeight) andController:self] retain];
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self.view addSubview:resultsTableVC.view];
[resultsTableVC release];
[self.view addSubview:favoritesTableVC.view];
[favoritesTableVC release];
}
Here is the order the methods are being called:
allResults init
resultsTableVC init
allResults viewDidLoad
addSubview allResultsVC
addSubview favoritesResultsVC
favoritesResultsVC init
This is a single thread, so I don't understand how viewDidLoad can be called before init is complete.
-[ResultsTableVC initWithController:andTableView:] is probably referencing allResults.view.
This would force the allResults controller to load its view (which then of course causes viewDidLoad to fire). All of this happens synchronously, before you actually return from initWithController:andTableView:
I'm taking a guess, but could you try this :
favoritesTableVC = [[[FavoritesTableVC alloc] initWithFrame:CGRectMake(0, 10, SOME_HARD_CODED_INT, SOME_HARD_CODED_INT) andController:self] retain];
And see if you get the same result.
My guess is that self.view is pointing to nil at that time.
But that wouldn't explain why the init is call after... but no harm in trying.
(I haven't tested it)
Please explain me why:
[inboxB setHidden:YES];
NSLog(#"is hidden ? %i", [inboxB isHidden]); // gives 0
inboxB is an outlet. I'm inside this initializer:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
...
thanks
Most likely inboxB is nil at the time when you set it.
Messages to nil fail silently and (almost) always return 0. So your code would look like:
[nil setHidden:YES]; // Does nothing
[nil isHidden]; // Returns 0 or 'NO'
If it's an outlet, check to make sure you've connected it to something.
I've run into this problem a few times with getters, I believe you need to access the property directly which calls isHidden which I believe is a private method.
Try:
indoxB.hidden;