ios - Object of array in new ViewController keeps empty -

i've problem array. there's array objects of class car in carviewcontroller:

...car.h

@interface car : nsobject @property (nonatomic, strong) nsstring *name; 

..and car.m

- (void)encodewithcoder:(nscoder *)coder; {     [coder encodeobject:name forkey:@"name"]; } - (id)initwithcoder:(nscoder *)coder; {     self = [[car alloc] init];     if (self != nil)     {         name = [coder decodeobjectforkey:@"name"];    }     return self; } 

and carviewcontroller

    car *car1 = [car new];         car1.name = @"a1"; ...      cars = [nsarray arraywithobjects: car1, car2, ..., nil]; 

but when try have access array in newviewcontroller there problem:

- (ibaction)btn:(id)sender {  uistoryboard *storyboard = [uistoryboard storyboardwithname:@"storyboard" bundle:nil]; carviewcontroller *vc = (carviewcontroller *)[storyboard instantiateviewcontrollerwithidentifier:@"carvc"];  car *car = [vc.cars objectatindex:0]; nslog(@"%@", car.name); } 

but in log written car.name = (null). in advance effort.

update:

- (ibaction)btn:(id)sender {   uinavigationcontroller *nav = self.tabbarcontroller.viewcontrollers[1];         carviewcontroller *vc = nav.topviewcontroller;         car *car = [vc.cars objectatindex:0];         nslog(@"%@", car.name); } 

i've tried (thanks rdelmar effort), result still same.

if put code

car *car1 = [car new];         car1.name = @"a1"; ...      cars = [nsarray arraywithobjects: car1, car2, ..., nil]; 

in viewdidload method of view controller, the result normal because view not loaded yet. (the viewdidload method has not been called yet)

i'm not familiar storyboards think when call

carviewcontroller *vc = (carviewcontroller *)[storyboard instantiateviewcontrollerwithidentifier:@"carvc"]; 

it instantiate new viewcontroller. if try access cars property nil if new viewcontroller not presented on screen

apple documentation

you use method create view controller objects want manipulate , present programmatically in application. before can use method retrieve view controller, must explicitly tag appropriate identifier string in interface builder.

this method creates new instance of specified view controller each time call it.