iOS - How does inheritance work? - ios

Question

I actually try to figure out how inheritance in Objective-C does work. My problem is, that my obj. allways returns "null".
Here is my Code:
Edit: Added rest of code.
// ReportViewController.h
#import <UIKit/UIKit.h>
#import <MessageUI/MessageUI.h>
#import "IAPHelper.h"
#class Report, Category, GADBannerView;
#interface ReportViewController : UIViewController <UIWebViewDelegate,
NSFetchedResultsControllerDelegate> {NSString* _werbung;}
#property (nonatomic, strong) GADBannerView *bannerView;
#property (nonatomic, retain) NSString* werbung;
- (id)initWithReport:(Report *)report category:(Category *)category ;
#end
// ReportViewController.m
#import "ReportViewController.h"
#import "IAPHelper.h"
#interface ReportViewController ()
- (void)loadReport;
- (void)setupFetchRequest;
- (void)resizeNavigationContentViewToHeight:(CGFloat)height;
- (NSString*) werbung;
- (void)setWerbung:(NSString *)newwerbung;
#end
#implementation ReportViewController
#synthesize werbung = _werbung;
-(NSString*) werbung {
return _werbung;
}
- (void)setWerbung:(NSString *)newwerbung {
_werbung= newwerbung;
}
//Werbung ausblenden
NSLog(#"Check for bought products");
if ([_werbung isEqual: #"gekauft"]) {
self.bannerView.hidden = TRUE;
}
- (void)viewDidLoad
{
[super viewDidLoad];
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)
{
self.edgesForExtendedLayout=UIRectEdgeNone;
self.navigationController.navigationBar.translucent = NO;
}
//ADMob
if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad) {
if([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortrait) {
_bannerView = [[GADBannerView alloc] initWithFrame: CGRectMake(20.0,850.0,728,90 )];}
if([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeRight) {
_bannerView = [[GADBannerView alloc] initWithFrame: CGRectMake(-10,615.0,728,90 )];}
if([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeLeft) {
_bannerView = [[GADBannerView alloc] initWithFrame: CGRectMake(-10,615.0,728,90 )];}
}
else
_bannerView = [[GADBannerView alloc] initWithFrame: CGRectMake(0,410,320,50 )];
//initWithAdSize:kGADAdSizeBanner];
//initwithframe:CGRectMake(0.0,0.0,320,50 )];
self.bannerView.adUnitID = #„xxxxxxxxxxxxxxxxx“;
self.bannerView.rootViewController = self;
GADRequest *request = [GADRequest request];
// Enable test ads on simulators.
[self.view addSubview:(_bannerView)];
request.testDevices = #[ GAD_SIMULATOR_ID, #„xxxxxxxxxxxxxxxxxxxxxxx“ ];
[self.bannerView loadRequest:request];
//Werbung ausblenden
NSLog(#"Check for bought products");
if ([_werbung isEqual: #"gekauft"]) {
self.bannerView.hidden = TRUE;
}
NSLog(#"%#",_werbung);
NSLog(#"%#",self.werbung);
}
// IAPHelper.m
#import "IAPHelper.h"
#import <StoreKit/StoreKit.h>
#import "ReportViewController.h"
#interface IAPHelper () <SKProductsRequestDelegate, SKPaymentTransactionObserver>
#end
#implementation IAPHelper
- (id)initWithProductIdentifiers:(NSSet *)productIdentifiers
{
//self = [super init];
if ((self = [super init])) {
// Store product identifiers
_productIdentifiers = productIdentifiers;
// Check for previously purchased products
_purchasedProductIdentifiers = [NSMutableSet set];
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
for (NSString * productIdentifier in _productIdentifiers) {
BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
if (productPurchased) {
[_purchasedProductIdentifiers addObject:productIdentifier];
NSLog(#"Previously purchased: %#", productIdentifier);
if ([productIdentifier isEqual:#"XXXXXXXXXXXXXXXXXXXXXXXXXX"]) {
ReportViewController *rvc = [[ReportViewController alloc] init];
rvc.werbung = #"gekauft";
NSLog(#"werbung gekauft!");
NSLog(#"%#", rvc.werbung); <- log's #"gekauft";
} else {
NSLog(#"Not purchased: %#", productIdentifier);
}
}
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
}}
return self;
}
My question is: What I did wrong? Maybe you got a good tutorial for me too?
EDIT: You were right, it was not about inheritance. My solution is working with UserDefaults.

Answer 1

This isn't a question of inheritance — inheritance governs what behaviour a subclass will acquire from its parent. The issue seems to be one of instances.
ReportViewController is a class. So it's not an actual actor. It's just the description of how any ReportViewControllers that are created will act. Like a constitution.
When you call alloc] init] you create one new instance of the view controller. You then set the advertisement as bought on that instance. You don't put the instance anywhere or otherwise keep hold of it. That instance therefore ceases to exist.
Elsewhere, in a completely different instance, you check the advertisement value. Nobody has told that instance anything. So you see the nil values.
Think of it exactly the same as NSString. In the code below, should stringB change value?
NSMutableString *stringA = [[NSMutableString alloc] init];
NSMutableString *stringB = [[NSMutableString alloc] init];
[stringA appendString:#"Mo' string for ya'"];

Answer 2

The ReportViewController that you're using to set the werbung value is not the same controller where you're checking the value. The one where you're doing the assignment is local to the method where it's being allocated.