Question

I was wondering how it is possible, to include certain restrictions inside an app, when the user loaded the free version of it.
For example: I have a tableView with around 100 entries. The user can favorite 10 of those, but not more, unless the user buys the premium version! I was thinking of just putting “return 10” in the numberOfRowsInSection on the FavoritetableViewController. Or is there a better/comfortabler way to do this?

There is also a commentary function. So if the user sees a comment, he/she wants to reply to, he/she only has to click on “answer”. But for free users I wanna limit that interaction by 5.
So they can write 5 comments a day. I was playing with the thought of implementing some sort of internal clock. And everytime the user clicks on “Submit” a counter goes up. And when the counter reaches 5, the button gets disabled. And after the clock has past 24 hours this count gets resetted. But to be honest I don’t know how to do that yet.
So any idea or input would be greatly appreciated.

Answer 1

I don’t know if it’s the best solution and if will help you. For me the way to do that is have a singleton class. You should initialize him at the app launching with a Bool var premium. At this moment you should initialize the class with all the data you need: number of favorite lines, comments the last day, ….

Before every “premium operation”, you should acces to a method like: BOOL authorized = [[AuthorizeSingleton sharedmanager] operation]. Here you will have all the test needed to know if he can perform the premium action.

You should acces to this singleton from a viewController every time someones wants to do a premium action. If the return is NO you pop a error message, in the other case you do the action.

If the user is premium always return yes.

Coded quickly something like that

Here the .h

#import <Foundation/Foundation.h>

@interface AuthorizeSingleton : NSObject
@property (strong, nonatomic) NSNumber* premium;
@end

Here the .m
#import AuthorizedSingleton.h

AuthorizeSingleton* _sharedInstance=nil;

@interface AuthorizeSingleton ()

@property (strong, nonatomic) NSDate* timestamp;
@property (strong, nonatomic) NSNumber* numberOfcomentary;
@end

@implementation AuthorizeSingleton
@synthesize timestamp=_timestamp, numberOfcomentary=_numberOfcomentary;

-(id)init{
     if (self == [super init]) {
    //Here you should take data from your persistence(NSUSerDefaults or something like that) Here I initialize at 0
         _timestamp=[[NSDate alloc] init];
         _numberOfcomentary= [NSNumber numberWithInt:0];
    }

     return self;
}

+(AuthorizeSingleton*)sharedInstance{
    if (!_sharedInstance) {
        _sharedInstance = [[AuthorizeSingleton alloc] init];
    }

    return _sharedInstance;
}

-(BOOL)shouldDoComentary{
    NSDate* today= [[NSDate alloc] init];
    NSTimeInterval interval = [_timestamp timeIntervalSinceDate: today];

    if (interval>60*60*24) {
        _timestamp=today;
        _numberOfcomentary= [NSNumber numberWithInt:0];
    }

    if (_numberOfcomentary.integerValue>5 && !_premium.boolValue) {
        return NO;
    }

    return YES;
}

@end

I don’t test it but that’s the idea. You call the class from where you want an authorization like

BOOL auth = [[AuthorizedSingleton sharedInstance] shouldDoComentary]
if(!auth){
    //show error 
}
else{
     //do action
}