Question

What I want:

On the iPhone user enters few values and tap on save button.
App should store the values in an instance of VehicleClass and add it to an NSMutableArray.

Hope you can help.

ViewController.h

#import <UIKit/UIKit.h>
#import "VehicleClass.h"

@interface ViewController : UIViewController

@property (weak, nonatomic) IBOutlet UITextField *producerTextField;
@property (weak, nonatomic) IBOutlet UITextField *modelTextField;
@property (weak, nonatomic) IBOutlet UITextField *pYearTextField;
@property (weak, nonatomic) IBOutlet UITextField *priceTextField;

@property (weak, nonatomic) NSMutableArray *carArray;
@property (weak, nonatomic) IBOutlet UILabel *statusLabel;


- (IBAction)addCar:(id)sender;
- (IBAction)showCars:(id)sender;

@end

ViewController.m

@synthesize producerTextField, modelTextField, pYearTextField, priceTextField, carArray;

- (void)viewDidLoad
{
    [super viewDidLoad];

    carArray = [NSMutableArray array];
}

- (IBAction)addCar:(id)sender
{
    VehicleClass *newVehic = [[VehicleClass alloc]initWithProducer:producerTextField.text 
                                                          andModel:modelTextField.text
                                                          andPYear:producerTextField.text
                                                          andPrice:priceTextField.text];

    [carArray addObject:newVehic];
    if (carArray != nil) {
        statusLabel.text = @"Car saved to array.";
    }
    else {
        statusLabel.text = @"Error, check your code.";
    }
}

VehicleClass.h

#import <Foundation/Foundation.h>

@interface VehicleClass : NSObject

@property (weak, nonatomic) NSString *producer;
@property (weak, nonatomic) NSString *model;
@property (weak, nonatomic) NSString *pYear;
@property (weak, nonatomic) NSString *price;


-(id)initWithProducer:(NSString *)varProducer 
             andModel:(NSString *)varModel 
             andPYear:(NSString *)varPYear 
             andPrice:(NSString *)varPrice; 

@end

VehicleClass.m

#import "VehicleClass.h"

@implementation VehicleClass

@synthesize model, price,pYear,producer;


-(id)initWithProducer:(NSString *)varProducer 
             andModel:(NSString *)varModel 
             andPYear:(NSString *)varPYear 
             andPrice:(NSString *)varPrice
{
    self = [super init];
    if (self != nil) 
    {
        producer = varProducer;
        model = varModel;
        pYear = varPYear;
        price = varPYear;
    }
    return self;
}

@end

Maybe the problem has something to do with my init method?

Answer 1

carArray is a weak property, it should be strong.

Also: you should use self.carArray and not carArray. When you use carArray, you are using the underlying iVar and not the actual property. It will cause confusion later.