UILabel doesn't update through modal presentation view controller - ios

Question

I have two class, PresentViewController and ModalViewController, In PresentViewController I call the ModalViewController in this format:
ModalViewController *targetController = [[ModalViewController alloc] init];
targetController.modalPresentationStyle = UIModalPresentationFormSheet;
targetController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:targetController animated:YES completion:nil];
// it is important to do this after presentModalViewController:animated:
targetController.view.superview.bounds = CGRectMake(0, 0, 400, 218);
In ModalViewController, I have a button who send a parameter to the class PresentViewController:
-(IBAction)apply{
PresentViewController *infoViewController = [[PresentViewController alloc] init];
[infoViewController setDiscount:[campoDesconto.text intValue]];
[self dismissViewControllerAnimated:YES completion:nil];
}
In PresentViewController the method setDiscount is as follows:
-(void)setDiscount:(int)value{
NSLog(#"Method is called!");
totalPrice.text = value;
}
This method is being called because I get a console message, but unfortunately this UILabel not updating your value, why this is happening and how can I solve?

Answer 1

When you call apply method, you haven't setup the view of infoViewController yet.
So you probably haven't created the totalPrice label yet, if you do NSLog(#"totalPrice: %#", totalPrice); in setDiscount:, it will probably output (null). You should save the discount value as a property, and set it in viewDidLoad as well as when setDiscount: method is called.
You're also setting an int to a NSString, this isn't correct.
PresentViewController.h
#interface PresentViewController : UIViewController
#property (nonatomic, assign) int discount;
#end
PresentViewController.m
#implementation PresentViewController
-(void)viewDidLoad
{
[super viewDidLoad];
// Setup detailLabel
detailLabel.text = [#(self.discount) stringValue];
}
-(void)setDiscount:(int)discount
{
_discount = discount;
detailLabel.text = [#(_discount) stringValue];
}
#end

Answer 2

That's because totalPrice is not probably instantiated before setDiscount: is called. Call setDiscount: after your view is loaded and totalPrice is instantiated to have the label text updated.