How to pass data between view controller in objective-c? - ios

Question

The select item is a slider. When I click the slider It will pass the data to Second VC (WebViewController). but how to pass data from first view controller to second view controller in objective-c? Sorry, This is my first time coding objective C.
First VC .m file
#import "WebViewController.h"
- (void)viewDidLoad {
[super viewDidLoad];
arraySliderProducts = [[NSMutableArray alloc]init];
}
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
[collectionView deselectItemAtIndexPath:indexPath animated:YES];
UIViewController *controller = nil;
switch (indexPath.row)
{
case 0:
{
WebViewController *WebViewController = [[WebViewController alloc] init];
//error: No visible #interface for "WebViewController" declares the selector 'alloc'
WebViewController.data = arraySliderProducts[indexPath.row][#"title"]; //pass this link value
//error: Property 'data' not found on object of type 'WebViewController'
[self.navigationController pushViewController: WebViewController animated:YES];
}..
Second VC .m file
#interface WebViewController ()
#property (nonatomic, retain) NSString *data;
Second VC .h file
#import <UIKit/UIKit.h>
#interface WebViewController : UIViewController
{
AppDelegate *appDelegate;
NSString *data;
}
#end

Answer 1

Two points to note:
1: This is not the way to initiate a view controller to show/present in your app.
2: You should declare your NSString *data in your SecondVC's .h file.
Now point 1 solutions is to change your code with below in your didSelectItemAtIndexPath: function
switch (indexPath.row)
{
case 0:
{
// By Default storyboard name is "Main". Change it if you you have different name in your project
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:#"Main" bundle: nil];
// Now instantiate your view controller with its identifier on this storyboard object.
// Note: don't forget to set viewControllers' identifier
WebViewController *vc = [mainStoryboard instantiateViewControllerWithIdentifier: #"WebViewController"];
// Now Pass your value
WebViewController.data = arraySliderProducts[indexPath.row][#"title"];
//Finally push this object on your navigation stack
[self.navigationController pushViewController: WebViewController animated:YES];
}...
}

Answer 2

try as
//Your class and obj name is same so You are getting this type of error
WebViewController *VC = [[WebViewController alloc] init];
//OR
WebViewController *VC= [self.storyboard instantiateViewControllerWithIdentifier:#"WebViewController"];
VC.data = arraySliderProducts[indexPath.row][#"title"];
[self.navigationController pushViewController: VC animated:YES];