Passing Data Between View Controllers Using a Segue from a View Embedded in a Navigation Controller to a Tabbarcontroller

Passing Data between view Controllers Using a segue from a view embedded in a navigation controller to a tabbarcontroller

This is my view controller where you can check that I am sending 5 to tabbar first viewcontroller:

   class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.performSegue(withIdentifier: "segueIdentifier", sender: self)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let barViewControllers = segue.destination as! UITabBarController
        let destinationNv = barViewControllers.viewControllers?[0] as! UINavigationController
        let destinationViewController = destinationNv.viewControllers[0] as! FirstViewController
        destinationViewController.currentBalance = 5
    }
}

Now You can check my firstview controller where you can check that what value we are getting.

class FirstViewController: UIViewController {

    var currentBalance = 0
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        print(currentBalance)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

Now, You can check my console and storyboard:
Sample Image

Sample Image

Segue to a view controller embedded with a tab and navigation controller

You have to change the tabBarController selected item index programmatically like this when the button is tapped,

self.tabBarController?.selectedIndex = 1 // 0 or 1 as you have two tab items

And you have to remove the segue for that ViewController 2 as it is the first ViewController in that tab so once you set the selectedIndex of tabBarController you will get that ViewController

How to pass data between view controller and the tab-bar's view controllers using segue?

I got my answer

    @IBAction func submitButonTapped(_ sender: Any) {
            performSegue(withIdentifier: "homePage", sender: self)
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let barViewControllers = segue.destination as! UITabBarController
        let destinationViewController = barViewControllers.viewControllers![0] as! ViewControllerB
        destinationViewController.containsData = Data
    }

Swift navigation controller embedded in tab bar with segue

First you have to select first index of TabbarController and then you have to push PurpleViewController onto the navigation controller like given below

It will solve your both issues

You will get Tabbar underneath PurpleViewController

secondly If you
press back button, you will get blueViewController

tabBarController?.selectedIndex = 0

if let navC = tabBarController?.viewControllers?.first as? UINavigationController {

   let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
   let nextViewController = storyBoard.instantiateViewController(withIdentifier: "purpleView") as! PurpleViewController
   navC.pushViewController(nextViewController, animated: true)

}

Hope it will help you.

How to segue to view controller from TabbarController?

Assuming that your storyboards looks similar to:

Sample Image

That's because you are calling performSegue(with: "identifier") in the TabbarController which does not directly connected to the segue. What you should do instead so to implement it in the first view controller which connected to the navigation controller (ViewControllerA). So, it would be -for instance- something like this:

class ViewControllerA: UIViewController {
    // ...

    override func viewDidLoad() {
        super.viewDidLoad()

        performSegue(with: "identifier")

    }

    // ...
}

Thus your segue should be from ViewControllerA to the desired view controller.

Passing data between view controllers

This question seems to be very popular here on Stack Overflow so I thought I would try and give a better answer to help out people starting in the world of iOS like me.

Passing Data Forward

Passing data forward to a view controller from another view controller. You would use this method if you wanted to pass an object/value from one view controller to another view controller that you may be pushing on to a navigation stack.

For this example, we will have ViewControllerA and ViewControllerB

To pass a BOOL value from ViewControllerA to ViewControllerB we would do the following.

in ViewControllerB.h create a property for the BOOL

 @property (nonatomic, assign) BOOL isSomethingEnabled;

in ViewControllerA you need to tell it about ViewControllerB so use an
```
 #import "ViewControllerB.h"
```

Then where you want to load the view, for example, didSelectRowAtIndex or some IBAction, you need to set the property in ViewControllerB before you push it onto the navigation stack.

    ViewControllerB *viewControllerB = [[ViewControllerB alloc] initWithNib:@"ViewControllerB" bundle:nil];
    viewControllerB.isSomethingEnabled = YES;
    [self pushViewController:viewControllerB animated:YES];

This will set isSomethingEnabled in ViewControllerB to BOOL value YES.

Passing Data Forward using Segues

If you are using Storyboards you are most likely using segues and will need this procedure to pass data forward. This is similar to the above but instead of passing the data before you push the view controller, you use a method called

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

So to pass a BOOL from ViewControllerA to ViewControllerB we would do the following:

in ViewControllerB.h create a property for the BOOL

 @property (nonatomic, assign) BOOL isSomethingEnabled;

in ViewControllerA you need to tell it about ViewControllerB, so use an
```
 #import "ViewControllerB.h"
```
Create the segue from ViewControllerA to ViewControllerB on the storyboard and give it an identifier. In this example we'll call it "showDetailSegue"

Next, we need to add the method to ViewControllerA that is called when any segue is performed. Because of this we need to detect which segue was called and then do something. In our example, we will check for "showDetailSegue" and if that's performed, we will pass our BOOL value to ViewControllerB

 -(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
     if([segue.identifier isEqualToString:@"showDetailSegue"]){
         ViewControllerB *controller = (ViewControllerB *)segue.destinationViewController;
         controller.isSomethingEnabled = YES;
     }
 }

If you have your views embedded in a navigation controller, you need to change the method above slightly to the following

    -(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
        if([segue.identifier isEqualToString:@"showDetailSegue"]){
            UINavigationController *navController = (UINavigationController *)segue.destinationViewController;
            ViewControllerB *controller = (ViewControllerB *)navController.topViewController;
            controller.isSomethingEnabled = YES;
        }
    }

This will set isSomethingEnabled in ViewControllerB to BOOL value YES.

Passing Data Back

To pass data back from ViewControllerB to ViewControllerA you need to use Protocols and Delegates or Blocks, the latter can be used as a loosely coupled mechanism for callbacks.

To do this we will make ViewControllerA a delegate of ViewControllerB. This allows ViewControllerB to send a message back to ViewControllerA enabling us to send data back.

For ViewControllerA to be a delegate of ViewControllerB it must conform to ViewControllerB's protocol which we have to specify. This tells ViewControllerA which methods it must implement.

In ViewControllerB.h, below the #import, but above @interface you specify the protocol.

 @class ViewControllerB;

 @protocol ViewControllerBDelegate <NSObject>
 - (void)addItemViewController:(ViewControllerB *)controller didFinishEnteringItem:(NSString *)item;
 @end

Next still in the ViewControllerB.h, you need to set up a delegate property and synthesize in ViewControllerB.m
```
 @property (nonatomic, weak) id <ViewControllerBDelegate> delegate;
```

In ViewControllerB we call a message on the delegate when we pop the view controller.

 NSString *itemToPassBack = @"Pass this value back to ViewControllerA";
 [self.delegate addItemViewController:self didFinishEnteringItem:itemToPassBack];

That's it for ViewControllerB. Now in ViewControllerA.h, tell ViewControllerA to import ViewControllerB and conform to its protocol.
```
 #import "ViewControllerB.h"

 @interface ViewControllerA : UIViewController <ViewControllerBDelegate>
```

In ViewControllerA.m implement the following method from our protocol

 - (void)addItemViewController:(ViewControllerB *)controller didFinishEnteringItem:(NSString *)item
 {
     NSLog(@"This was returned from ViewControllerB %@", item);
 }

Before pushing viewControllerB to navigation stack we need to tell ViewControllerB that ViewControllerA is its delegate, otherwise we will get an error.

 ViewControllerB *viewControllerB = [[ViewControllerB alloc] initWithNib:@"ViewControllerB" bundle:nil];
 viewControllerB.delegate = self
 [[self navigationController] pushViewController:viewControllerB animated:YES];

References

Using Delegation to Communicate With Other View Controllers in the View Controller Programming Guide
Delegate Pattern

NSNotification center

It's another way to pass data.

// Add an observer in controller(s) where you want to receive data
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleDeepLinking:) name:@"handleDeepLinking" object:nil];

-(void) handleDeepLinking:(NSNotification *) notification {
    id someObject = notification.object // Some custom object that was passed with notification fire.
}

// Post notification
id someObject;
[NSNotificationCenter.defaultCenter postNotificationName:@"handleDeepLinking" object:someObject];

Passing Data back from one class to another (A class can be any controller, Network/session manager, UIView subclass or any other class)

Blocks are anonymous functions.

This example passes data from Controller B to Controller A

Define a block

@property void(^selectedVoucherBlock)(NSString *); // in ContollerA.h

Add block handler (listener)

Where you need a value (for example, you need your API response in ControllerA or you need ContorllerB data on A)

// In ContollerA.m

- (void)viewDidLoad {
    [super viewDidLoad];
    __unsafe_unretained typeof(self) weakSelf = self;
    self.selectedVoucherBlock = ^(NSString *voucher) {
        weakSelf->someLabel.text = voucher;
    };
}

Go to Controller B

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
ControllerB *vc = [storyboard instantiateViewControllerWithIdentifier:@"ControllerB"];
vc.sourceVC = self;
    [self.navigationController pushViewController:vc animated:NO];

Fire block

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:
(NSIndexPath *)indexPath {
    NSString *voucher = vouchersArray[indexPath.row];
    if (sourceVC.selectVoucherBlock) {
        sourceVC.selectVoucherBlock(voucher);
    }
    [self.navigationController popToViewController:sourceVC animated:YES];
}

Another Working Example for Blocks

Swift passing data between Nav and Tab Controller

Give your tab bar controller a custom class, for example MyTabBarController, and declare a variable there that will receive the text from your textfield in log in view controller (via prepareForSegue). then you will be able to access that variable from your home view controller.

In your log in view controller:

    @IBAction func ButtonPressed(sender: AnyObject) {

    performSegueWithIdentifier("toTabBarController", sender: nil)

    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if let tabBarController = segue.destinationViewController as? MyTabBarController{

        tabBarController.someVariable = someTextField.text!

        }

    }

in your tab bar controller:

var someVariable = String()

in you home tableview controller:

    override func viewWillAppear(animated: Bool) {

        let tabBarController = self.tabBarController as! MyTabBarController
        someVariable = tabBarController.someVariable

    print("the text is",someVariable)

}