iOS开发：如何从FourthController跳转回嵌入的初始页面？

Got it, let's break down how to add that restart functionality cleanly, fitting with your existing parent-child controller architecture. The best approach here is using a delegate pattern—it keeps your code decoupled and aligns with how your app already manages controller swaps.

Step 1: Add Delegate Protocol to FourthController #

First, define a protocol in FourthController to communicate the restart action back to the parent ViewController, then add a button tap handler:

import UIKit

// Define a delegate protocol for restart events
protocol FourthControllerDelegate: AnyObject {
    func didRequestRestart()
}

class FourthController: UIViewController {
    var survey: Survey!
    // Weak reference to avoid retain cycles
    weak var delegate: FourthControllerDelegate?

    // Connect this IBAction to your restart button in Storyboard
    @IBAction func restartTapped(_ sender: UIButton) {
        // Notify the parent controller to handle restart
        delegate?.didRequestRestart()
    }

    // Your existing FourthController code...
}

Step 2: Make ViewController Conform to the Delegate #

Update your main ViewController to adopt the delegate protocol and implement the restart logic—reusing your existing moveAndSizeChildControllers method to keep consistency:

extension ViewController: FourthControllerDelegate {
    func didRequestRestart() {
        // Instantiate the FirstController
        guard let firstController = storyboard?.instantiateViewController(withIdentifier: "FirstController") as? FirstController else {
            return
        }
        
        // Reset survey data if needed (use self.survey if you want to keep existing data)
        firstController.survey = Survey()
        
        // Swap the current controller with FirstController
        if let currentController = currentController {
            moveAndSizeChildControllers(fromController: currentController, toController: firstController)
            // Reset page index to initial state
            pageIndex = 1
            setButtonAndProgressLabel()
        }
    }
}

Step 3: Assign the Delegate When Navigating to FourthController #

In your ViewController's nextTapped method, set the delegate for FourthController when you instantiate it:

case 3:
    let nextController = storyboard?.instantiateViewController(withIdentifier: "FourthController")
    if let fromController = currentController, let toController = nextController as? FourthController {
        toController.survey = survey
        // Set the delegate to self so FourthController can notify us
        toController.delegate = self
        moveAndSizeChildControllers(fromController: fromController, toController: toController)
        pageIndex += 1
        setButtonAndProgressLabel()
    }

Why This Works #

• Low Coupling: FourthController doesn't need to know anything about ViewController's internal logic—it just signals that a restart is requested.
• Consistency: Reuses your existing controller swap method, so the animation and state management stays identical to your forward/back navigation.
• Memory Safe: Using a weak delegate reference prevents retain cycles.

Alternative: Notification Center (Less Recommended) #

If you prefer a looser connection, you could use NotificationCenter, but this is overkill for a direct parent-child relationship:

// In FourthController's restartTapped
NotificationCenter.default.post(name: NSNotification.Name("RestartSurvey"), object: nil)

// In ViewController's viewDidLoad
NotificationCenter.default.addObserver(self, selector: #selector(handleRestart), name: NSNotification.Name("RestartSurvey"), object: nil)

// Add handler in ViewController
@objc func handleRestart() {
    // Same restart logic as the delegate method
}

// Don't forget to remove observer in deinit
deinit {
    NotificationCenter.default.removeObserver(self)
}

内容的提问来源于stack exchange，提问作者Kunduri Raj