UIAlertview Delegate Method not calling in Child View Controller

Question

I have two controllers

VC A -> Parent and VC B -> Child

Alert view delegate method i.e

func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int){}

is declared in VC A.

When i display alert from VC B delegate method is not called on alert button clicked.

Add the whole code, how are you setting and calling delegate method? — iphonic, Jan 16 '17 at 06:32
func showAlert(){ var createAccountErrorAlert: UIAlertView = UIAlertView() createAccountErrorAlert.delegate = self createAccountErrorAlert.tag = sender.tag createAccountErrorAlert.accessibilityIdentifier = "ReportAbuse" createAccountErrorAlert.title = "Confirm" createAccountErrorAlert.message = "Testing Alert" createAccountErrorAlert.addButtonWithTitle("Cancel") createAccountErrorAlert.addButtonWithTitle("Ok") createAccountErrorAlert.show() } — Aabid Khan, Jan 16 '17 at 06:39
when i call showAlert() from child vc i.e VC B delegate method is not called — Aabid Khan, Jan 16 '17 at 06:40
show the code of VC A , Parent VC B, and Child so that we can understand the problem better and tell you the solution.. — Anil Kumar, Jan 16 '17 at 06:43

score 0 · Answer 1 · answered Jan 16 '17 at 07:16

protocol alertViewDelegate:class {
    func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int)
}

Create an alert view delegate object in parent class VC A

weak var delegate:alertViewDelegate() ?= nil

Implement the delegate in VC B and Set the delegate object in VC B

let alertview = alertView()
alertview.delegate  = self

score 0 · Answer 2 · answered Jan 16 '17 at 09:36

0

You are setting AlertView delegate to self, Self means Child, Change delegate to VC A.

alertView.delegate = self.parent?.parent

answered Jan 16 '17 at 09:36

Morteza Soleimani

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nayem · Answer 3 · 2017-01-17T04:59:24.303

Follow these step by step:

Create a protocol in your VC-B as:

protocol AlertViewProtocol:class {
    func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int)
}

Add a var in your VC-B class as:
```
var delegate: AlertViewProtocol?
```
Use the delegate in any class method of VC-B to send the data to the receiving method (i.e. any method of VC-A), which is any method that adopts the protocol. Follow this pattern to use the delegate:
```
delegate?.alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int)
// Above statement is like a method calling (on delegate var), use your parameters accordingly
```

Adopt the protocol in your recieving class (here, VC-A):

class ViewControllerA: UIViewController, AlertViewProtocol {
...
...
}

Implement the delegate method in VC-A:

func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int) {
    // Do your stuff
    // when you click on the designated button in your VC-B, this method will be invoked
}

Set the delegate in VC-A where you are instantiating the VC-B object. In my case this is like:

Here, vcb?.delegate = self is very important. If you forget to set the delegate property of the object with self the delegation process won't work.

    @IBAction func showVCB(sender: AnyObject) {
        let vcb: ViewControllerB? = self.storyboard?.instantiateViewControllerWithIdentifier("viewcontrollerB") as? ViewControllerB
        vcb?.delegate = self
        self.presentViewController(vcb!, animated: true, completion: nil)
    }

Hope, this helps you for understanding the process of how the delegates work.

UIAlertview Delegate Method not calling in Child View Controller

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