Question

In my presenting view controller, I have the following prepareForSegue function

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if([[segue identifier] isEqualToString:@"goToView2"]){
        ViewController2 *controller2 = [segue destinationViewController];
        controller2.multiplierStepper.value = 7.0;
        controller2.randomString = @"string set from Scene 1";
    }
}

In ViewController2 there is an outlet for my UIStepper’s value and an NSString

@property (strong, nonatomic) IBOutlet UIStepper *multiplierStepper;
@property (strong, nonatomic) NSString *randomString;

In ViewController2.m viewDidLoad, I am testing the values set above by the presenting view controller

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.        
    NSLog(@"in viewDidLoad: self.multiplierStepper.value: %f", self.multiplierStepper.value);
    NSLog(@"in viewDidLoad: randomstring: %@", self.randomString);
}

The console output works nicely for the NSString, but the UIStepper value always shows the initial value defined in the Interface Builder (1).

[10682:f803] in viewDidLoad: self.multiplierStepper.value: 1.000000
[10682:f803] in viewDidLoad: randomstring: string set from Scene 1

The answer is probably glaringly obvious, but I cannot figure out how to set the value of a stepper in my destination view controller from the presenting view controller.

Any ideas what I’m doing wrong?

Answer 1

Do not set directly the value of the UIStepper in the the prepareForSeque method , it will not work !

You have to declare a property that will contains the value and then set the value of the stepper in the viewDidLoad event of the second controller …

First of all declare an additional property to your second view controller (ViewController2) header file :

@property (nonatomic) double stepperValue;

Then set the property value :

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if([[segue identifier] isEqualToString:@"goToView2"]){
        ViewController2 *controller2 = [segue destinationViewController];
        controller2.stepperValue = 7.0;
        controller2.randomString = @"string set from Scene 1";
    }
}

Then in the destination viewController (ViewController2) :

- (void)viewDidLoad
{
    multiplierStepper.value = [self stepperValue];
}

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Note

Bear in mind that the best thing for encapsulation would be declaring the IBOutlet as private member of the class, to avoid that a client of the class can access directly the IBOutlet; to make an IBOutlet private you have to declare it in a class extension in the .m file …