在AlerView的操作按钮上将文本设置为TextView，然后单击[iOS，Swift]

Question

I've created UIAlertController with Three action buttons, now I want to set text to a TextView on each button. Problem is this that when I click a button then result of previously clicked button is printed on TextView .

My Code

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var mTextView: UITextView!

    override func viewDidLoad() {
        super.viewDidLoad()
        mTextView.text = ""
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func showDialogOnClick(_ sender: UIButton) {

        //Creating UIAlert, giving its title and message, setting style(alert OR alertSheet)
        let mDialog = UIAlertController(title: "Title", message: "This is the message" , preferredStyle: .actionSheet)

        //add actions/buttons to alert
        mDialog.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: {(action) in
            print("Cancel")
            self.mTextView.text = "Cancel"
        }))
        mDialog.addAction(UIAlertAction(title: "Default", style: .default, handler: {(action) in
            print("Default")
            self.mTextView.text = "Default"
        }))
        mDialog.addAction(UIAlertAction(title: "Destructive", style: .destructive, handler: {(action) in
            print("Destructive")
            self.mTextView.text = "Destructive"
        }))

        self.present(mDialog, animated: true)

    }

}

Answer 1

What i think can be possible issue is you are testing this in your Simulator and your computer is having low graphic configuration same thing happens with be when i test my code in my old mac mini.You can do two things :-

1. Test the code in a physical device
2. Try to minimize your app in your simulator and come back to the app you'll see the effect Or change the view back and forth to see the effect.

Let me know if I was right.