Null variable in Objective C - objective-c

Question

I'm developing an iOS application and I'm having some problems when I try to save data.
My code is:
TuplaUsuario:
It is a class where I save user data. In that case, I use mensaje variable, so here is its code:
//TuplaUsuario.h:
#interface TuplaUsuario : NSObject
{
NSMutableString* mensaje;
}
#property NSMutableString* mensaje;
#end
//TuplaUsuario.m:
#import "TuplaUsuario.h"
#implementation TuplaUsuario
#synthesize mensaje;
- (id)initWithString:(NSString *)identifier {
if ( self = [super init] ) {
mensaje = [[NSMutableString alloc] initWithString:identifier];
}
return self;
}
#end
WebService:
It is a class where I communicate with a Web Service.
//WebService.h:
#import "TuplaUsuario.h"
#interface WebService : NSObject {
// Some other data
NSMutableString* message;
TuplaUsuario* usuario;
}
//Declaration of methods
#end
//WebService.m:
#import "WebService.h"
#import "AppDelegate.h"
#implementation WebService
- (id)init:(NSString *)identifier {
self = [super init];
usuario = [[TuplaUsuario alloc] initWithString:#""];
return self;
}
- (void) processComplete: (BOOL)success {
[[self delegate] processSuccessful:success];
AppDelegate* myAppDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
[myAppDelegate setUsuarioActual:usuario];
}
- (void)login:(NSString *)username password:(NSString *)password
{
//Connection with Web Service
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData {
NSDictionary* jsonArray=[NSJSONSerialization
JSONObjectWithData:theData
options:0
error:nil];
message = [jsonArray objectForKey:#"message"];
[usuario setMensaje:message];
}
AppDelegate:
//AppDelegate.h:
#import <UIKit/UIKit.h>
#import "TuplaUsuario.h"
#interface AppDelegate : UIResponder <UIApplicationDelegate>
{
Boolean rememberMe;
TuplaUsuario* usuarioActual;
}
#property (strong, nonatomic) UIWindow *window;
#property (retain) TuplaUsuario* usuarioActual;
#end
//AppDelegate.m:
#import "AppDelegate.h"
#implementation AppDelegate
#synthesize usuarioActual;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
usuarioActual = [[TuplaUsuario alloc] initWithString:#""];
return YES;
}
PROBLEM
In WebService, method connection didReceiveData, if I print message variable, it has the correct value, but if I print [usuario mensaje] it prints (null).
Where's my error?
SOLVED
The problem was in my ViewController and init method of WebService. I called init instead of initWithString:
ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
wSProtocol = [[WebService alloc] initWithString:#""]; //Variable of type WebService
}
WebService
- (id)initWithString:(NSString *)identifier {
self = [super init];
usuario = [[TuplaUsuario alloc] initWithString:#""];
return self;
}

Answer 1

Maybe because this method:
- (id)init:(NSString *)identifier {
if ( self = [super init] ) {
mensaje = [[NSMutableString alloc] init];
}
return self;
}
is never called, since you use:
usuario = [[TuplaUsuario alloc] init];
but is still wonder why you pass identifier into the method and never use it. I think you should make it like this:
mensaje = [[NSMutableString alloc] initWithString:identifier];