How to pass value from subclass to super class during initialization - ios

Question

Suppose, I've two view controller. ViewController1 is the sub class of ViewController2. From subclass (ViewController1), I called superclass init method & passed a value by parameter & assigned that value to the superclass variable. But In superclass (ViewController2)'s viewDidLoad method, that value is always null. Why ? How can I pass that value from sub to super so that I can get that value in super class's viewDidLoad method ?
ViewController1.h
#interface ViewController : ViewController2
#end
ViewController1.m
#implementation ViewController
- (instancetype)init
{
self = [super initWithName:#"Hello"];
if (self) {
NSLog(#"1 :");
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
ViewController2.h
#interface ViewController2 : UIViewController
#property (nonatomic, strong) NSString *name;
-(instancetype)initWithName:(NSString *)name;
#end
ViewController2.m
- (instancetype)initWithName:(NSString *)name
{
self = [super init];
if (self) {
self.name = name;
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
NSLog(#"2 : %#", self.name);
}
#end

Answer 1

I tired your code and it worked just fine. I suspect, that you don't instantiate your ViewController directly. Do you use storyboard in your project? If yes - you should override initWithCoder: in ViewController.
However, it is bad idea to set any properties of view controllers during init-family methods. According to Apple recommendations, all customisation should be done in -viewDidLoad or -viewWill/DidAppear methods.
If you absolutely in need to set name property from outside, it is better you assign it directly, not trough passing argument to init method.
One more thing - initWithNibName:bundle: is Designated initializer. It means, that your subclasses absolutely must in the end call it during initialisation chain.

Answer 2

Updated - 16-Mar-2016
Example :
ViewController1.h
#import <UIKit/UIKit.h>
#import "ViewController2.h"
#interface ViewController1 : ViewController2
#end
ViewController1.m
#import "ViewController1.h"
#interface ViewController1 ()
#end
#implementation ViewController1
-(instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
//self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil andUserName:#"Ramesh Annadurai"];
// we can use above init method or below method, both will work
self = [super initWithName:#"Test Name"];
if (self) {
[self.view setBackgroundColor:[UIColor brownColor]];
}
return self;
}
-(instancetype)initWithCoder:(NSCoder *)aDecoder
{
//self = [super initWithCoder:aDecoder];
// If you are using storyboard use this initWithCoder method.
self = [super initWithName:#"Test Name"];
if (self) {
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
#end
ViewController2.h
#import <UIKit/UIKit.h>
#interface ViewController2 : UIViewController
- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil andUserName:(NSString *) userName;
- (instancetype)initWithName:(NSString *) userName;
#end
ViewController2.m
#import "ViewController2.h"
#interface ViewController2 ()
#property (strong, nonatomic) NSString *userName;
#end
#implementation ViewController2
- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil andUserName:(NSString *) userName
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.userName = userName;
}
return self;
}
- (instancetype)initWithName:(NSString *) userName
{
self = [super initWithNibName:nil bundle:nil];
if (self) {
self.userName = userName;
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"User Name : %#", self.userName);
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
#end