Object initialized in "init" cannot be accessed in "viewDidLoad" - ios

Question

I have a strange issue: I load object data in "init" method. When I try to access it in the "viewDidLoad" my app crashes. Here is the code:
#interface UploadCenterViewController () {
NSMutableArray *videos;
}
#end
#implementation UploadCenterViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
if (![self loadVideos]) {
[self saveVideos];
}
}
return self;
}
-(void)saveVideos {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *encodedData = [NSKeyedArchiver archivedDataWithRootObject:videos];
[defaults setObject:encodedData forKey:#"VIDEOS"];
[defaults synchronize];
}
-(bool)loadVideos {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *encodedData = [defaults objectForKey:#"VIDEOS"];
if (encodedData) {
videos = (NSMutableArray *)[NSKeyedUnarchiver unarchiveObjectWithData:encodedData];
NSLog(#"array size: %d", [videos count]);
return true;
} else {
videos = [[NSMutableArray alloc] init];
return false;
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"%d", [videos count]);
}
When loading the data, the "videos" array contains an object. When accessing it in the "viewDidLoad" the entire app crashes.
Does anyone has an idea?

Answer 1

Declare videos as an #property and use it as self.videos everywhere. The crash is due to the fact that videos is getting released once you assign a value to it. The scope of videos is only inside that method and it can crash due to this. Since you want to use this outside that method, you need to retain it and you can use #property for this as mentioned below.
for eg:-
#interface UploadCenterViewController () {}
#property(nonatomic, strong) NSMutableArray *videos;
#end
-(void)saveVideos {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *encodedData = [NSKeyedArchiver archivedDataWithRootObject:self.videos];
[defaults setObject:encodedData forKey:#"VIDEOS"];
[defaults synchronize];
}
-(bool)loadVideos {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *encodedData = [defaults objectForKey:#"VIDEOS"];
if (encodedData) {
self.videos = (NSMutableArray *)[NSKeyedUnarchiver unarchiveObjectWithData:encodedData];
NSLog(#"array size: %d", [self.videos count]);
return true;
} else {
self.videos = [[NSMutableArray alloc] init];
return false;
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"%d", [self.videos count]);
}

Answer 2

You might want to retain the result of [NSKeyedUnarchiver unarchiveObjectWithData:encodedData].
Read the memory management rules.