Display Alert Message from viewDidLoad

Question

I want to display a alert message from viewDidLoad() method of ViewController.m instead from viewDidAppear() method.

Here is m

Answer 1

Swift 3 iOS 10, I used operation queue to put the block of code that updates the UI onto the main thread.

import UIKit

class ViewController2: UIViewController {

var opQueue = OperationQueue()

override func viewDidLoad() {
    super.viewDidLoad()
        let alert = UIAlertController(title: "MESSAGE", message: "HELLO WORLD!", preferredStyle: UIAlertControllerStyle.alert)
        // add an action (button, we can add more than 1 buttons)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
        // show the alert
        self.opQueue.addOperation {
            // Put queue to the main thread which will update the UI
            OperationQueue.main.addOperation({
                self.present(alert, animated: true, completion: nil)
            })
        }
    }
}

In short we are using async. This allows the alert message to be displayed as expected (even when we are in viewDidLoad()).