Implement fix for: AlertView offset is not restored after dismissing … (

#324)

Co-authored-by: swilliams <[email protected]>

Source/AlertController.swift

@@ -289,12 +289,15 @@ public final class AlertController: UIViewController {
 
     private func listenForKeyboardChanges() {
         NotificationCenter.default
-            .addObserver(self, selector: #selector(self.keyboardChange),
-                         name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
+            .addObserver(self, selector: #selector(keyboardWillShow),
+                         name: UIResponder.keyboardWillShowNotification, object: nil)
+        NotificationCenter.default
+            .addObserver(self, selector: #selector(keyboardWillHide),
+                         name: UIResponder.keyboardWillHideNotification, object: nil)
     }
 
     @objc
-    private func keyboardChange(_ notification: Notification) {
+    private func keyboardWillShow(notification: NSNotification) {
         let newFrameValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue
         guard let newFrame = newFrameValue?.cgRectValue else {
             return
@@ -304,6 +307,12 @@ public final class AlertController: UIViewController {
         self.alert.layoutIfNeeded()
     }
 
+    @objc
+    private func keyboardWillHide(notification: NSNotification) {
+        self.verticalCenter?.constant = 0
+        self.alert.layoutIfNeeded()
+    }
+
     private func configureAlertView() {
         self.alert.translatesAutoresizingMaskIntoConstraints = false
         self.alert.visualStyle = self.visualStyle