How to set/get UIImageView.image through Singleton? - objective-c

Question

I have two ViewControllers.
FirstViewController has UILabels and UIImageViews. Also generated a Singleton from its class.
SecondViewController has a call of that Singleton and should GET values of UILabels and UIImageViews from FirstViewController.
NSString works, UILabel do not.
For example, access a NSString in SecondviewController with "sharedFirstViewController.nsstringvarname" I can GET and SET the value.
This works fine!
Trying the same with an UILabel like this: "sharedFirstViewController.uilabelvar.text" I doens´t can SET or GET the value of this UILable.
This works NOT!
Is there any special thing with UI-Objects?
Would be great if someone can help me with that.
Thanks!
EDIT:
in FirstViewController.h
+ (id)sharedFirstViewController;
#property (copy, nonatomic) NSString *path;
#property (strong, nonatomic) IBOutlet UIImageView *pic;
in FirstViewController.m
#synthesize path= _path;
#synthesize pic = _pic;
- (id)init {
if (self = [super init]) {
_pic = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 100, 200)];
}
return self;
}
+ (id) sharedFirstViewController {
static sharedFirstViewController * sharedFirstViewController = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedFirstViewController = [[self alloc] init];
});
return sharedFirstViewController;
}
in SecondViewController.m
#import "FirstViewController.h"
- (void)viewDidLoad
{
FirstViewController * sharedFirstViewController = [FirstViewController sharedFirstViewController];
NSLog(#"this is NSString from FVC: %#" sharedFirstViewController.path); //works
UIImage * picture = [UIImage imageWithContentsOfFile:sharedFirstViewController.path];
sharedFirstViewController.pic.image = picture; // does´t work
}

Answer 1

I'm sure you forget to give allocation to UIImageview *pic in init method of singleton class. That because your code running but without any crash and warning. If you debug your code you will get imageview memory allocation 0X0. check it.
- (id)init {
if (self = [super init]) {
_pic = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 100, 200)];
}
return self;
}
write above method in in FirstViewController.m class. Their is doesn't need of write IBOutlet in front of UIImageView *pic because you not mention your viewcontroller nib while generation singleton instance. Use IBOutlet whenever you dealing UI in xib.