CODEWITHSUNDEEP
iosswiftobjective-cuiviewcontroller
DroidDev
DroidDev

Reputation: 789

iOS - Pass Data from Swift to ObjC VC using protocol and delegate

I am trying to pass data back from Swift VC2 to ObjC VC1 using delegates while dismiss, below is my code.

VC2 (swift)

//protocol used for sending data back
@objc protocol DataEnteredDelegate: AnyObject {
    func userDidEnterInformation(info: String)
}

class VC2: UIViewController {

    weak var delegate: DataEnteredDelegate? = nil

    // **Go back to VC1**
    @IBAction func doneBtn(_ sender: Any) { 
      session.stop();
      delegate!.userDidEnterInformation(info: "sending date from Swift VC2")
      self.dismiss(animated: true, completion: nil) 
    }
}

VC1.m (objc)

#import "ProjectName-Swift.h"

@interface VC1 () <>
 
@end

@implementation VC1
// **Navigate to VC2**
-(void)goToVC2 {
    VC2 *vc2 = [[UIStoryboard storyboardWithName: @"Main" bundle:nil] instantiateViewControllerWithIdentifier:@"VC2ID"];
    [self presentViewController: vc2 animated: YES completion: nil];
}
@end

VC1.h (objc)

@interface VC1 : UIViewController

@end

How to assign the delegate in VC1 before moving to VC2 and how to implement protocol in VC1 (objc) file i.e. DataEnteredDelegate and the func userDidEnterInformation.

I believe I have completed the swift part of the task but looking for Objc implementation.

Upvotes: 0

Views: 738

Answers (2)

Sahidul Islam
Sahidul Islam

Reputation: 139

First you need to create delegate instance initial with @objc

VC2 (swift)

//protocol used for sending data back
@objc protocol DataEnteredDelegate: AnyObject {
    func userDidEnterInformation(info: String)
}

class VC2: UIViewController {

   @objc weak var delegate: DataEnteredDelegate?

    // **Go back to VC1**
    @IBAction func doneBtn(_ sender: Any) { 
      session.stop();
      delegate!.userDidEnterInformation(info: "sending date from Swift VC2")
      self.dismiss(animated: true, completion: nil) 
    }
}

Now in objective-c, VC1.m (objc)

#import "ProjectName-Swift.h"

@interface VC1 () <DataEnteredDelegate>
 
@end

@implementation VC1
// **Navigate to VC2**
-(void)goToVC2 {
    VC2 *vc2 = [[UIStoryboard storyboardWithName: @"Main" bundle:nil] instantiateViewControllerWithIdentifier:@"VC2ID"];
    [vc2 delegate:self];
    [self presentViewController: vc2 animated: YES completion: nil];
}

//On dismiss vc2 this delegate will call
- (void)userDidEnterInformationWithInfo:(NSString *)info{
    NSLog(@"%@", info);
}
@end

Upvotes: 0

DonMag
DonMag

Reputation: 77700

Very basic example...

Assuming we have in Storyboard:

  • an Objective-C controller ObjcViewController with a "Present It" button
  • a Swift controller SwiftViewController with a "Done" button, with Identifier: "SwiftVC"

and the buttons are connected to the IBAction methods...

ObjcViewController.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface ObjcViewController : UIViewController

@end

NS_ASSUME_NONNULL_END

ObjcViewController.m

#import "ObjcViewController.h"

#import "YourProject-Swift.h"

@interface ObjcViewController () <DataEnteredDelegate>

@end

@implementation ObjcViewController

- (IBAction)goToSwiftVC:(id)sender {
    
    SwiftViewController *vc = (SwiftViewController *)[self.storyboard instantiateViewControllerWithIdentifier:@"SwiftVC"];
    [vc setMyDelegate:self];
    [self presentViewController:vc animated:YES completion:nil];
    
}

- (void)userDidEnterInformationWithInfo:(NSString * _Nonnull)info {
    NSLog(@"Delegate sent back: %@", info);
}

@end

SwiftViewController.swift

import UIKit

@objc public protocol DataEnteredDelegate {
    func userDidEnterInformation(info: String)
}

class SwiftViewController: UIViewController {

    @objc public var myDelegate: DataEnteredDelegate?
    
    @IBAction func doneBtn(_ sender: Any) {
        myDelegate?.userDidEnterInformation(info: "from SwiftVC")
        self.dismiss(animated: true, completion: nil)
    }

}

Upvotes: 1

Related Questions