How to access property in different view controller? - ios

Question

I have two storyboards and each one has its own respective view controller but I need to change the appearance of the second storyboard based on the button pressed in the first view controller.
In the first view controller I have:
// First view controller .h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"
#interface FirstViewController : UIViewController
#property (strong, nonatomic) IBOutlet UIButton *LevelOneButton; // tag 0
#property (strong, nonatomic) IBOutlet UIButton *LevelTwoButton; // tag 1
-(IBAction)selectLevel:(UIButton *)sender; // both buttons connected to this method
#property (assign, nonatomic) int levelSelect;
#end
then in the first .m file:
//FirstViewController.m
-(IBAction)selectLevel:(UIButton *)sender {
if (sender.tag == 0) {
_levelSelect = 0;
}
if (sender.tag == 1) {
_levelSelect = 1;
}
}
This code works fine but the problem occurs in the secondViewController that I have. When I try and access the levelSelect property in the SecondViewController I get the errors "Property 'levelSelect' not found on object of type 'FirstViewController'" or "Unexpected identifier levelSelect" or something among those lines. I've tried every single thing I could think of and every question I found on StackOverflow relating to this but none have fixed the problem. Anyone know what I'm doing wrong?

Answer 1

You should be setting the property on the second view controller as you're pushing or segueing.
So in your first view controller it should look something like this:
#import "ViewController.h"
#import "SecondViewController.h"
#interface ViewController ()
#property (strong, nonatomic) IBOutlet UIButton *levelOne;
#property (strong, nonatomic) IBOutlet UIButton *levelTwo;
#property (assign, nonatomic) int selectedLevel;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.levelOne.tag = 1;
self.levelTwo.tag = 2;
}
- (IBAction)selectLevel:(UIButton *)sender
{
if (sender.tag == 1) {
self.selectedLevel = 1;
} else {
self.selectedLevel = 2;
}
[self performSegueWithIdentifier:#"pushToSecond" sender:self];
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
SecondViewController *dest = segue.destinationViewController;
dest.levelSelect = self.selectedLevel;
}
#end
Now, when viewDidLoad gets called on the SecondViewController that property will be set and you can use it. Like so:
#import "SecondViewController.h"
#interface SecondViewController ()
#property (strong, nonatomic) IBOutlet UILabel *levelLabel;
#end
#implementation SecondViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.levelLabel.text = [#(self.levelSelect) stringValue];
}
#end
Quick Edit, if you're not using segues you can do the same thing by pushing manually. Would look something like:
- (IBAction)selectLevel:(UIButton *)sender
{
if (sender.tag == 1) {
self.selectedLevel = 1;
} else {
self.selectedLevel = 2;
}
SecondViewController *secondVC = [[UIStoryboard storyboardWithName:#"Main" bundle:[NSBundle mainBundle]] instantiateViewControllerWithIdentifier:#"second"];
secondVC.levelSelect = self.selectedLevel;
[self.navigationController pushViewController:secondVC animated:YES];
}