How to create Custom UIAlertController in swift ios?

What you are trying to do is a popover, for current versions of iOS you can achieve the same effect for both iPad and iPhone.

1.- Start by building your design on Storyboard or a xib. and then reference it.

2.- then present it as a popover.

3.- maybe you will want to implement popoverdelegates to avoid wrong positions when rotating the device.

for example:

  private static func presentCustomDialog(parent: UIViewController) -> Bool {
        /// Loads your custom from its xib or from Storyboard
        if let rateDialog = loadNibForRate() {
            rateDialog.modalPresentationStyle = UIModalPresentationStyle.Popover
            rateDialog.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
            let x = parent.view.center

            let sourceRectX : CGFloat

            let maximumDim = max(UIScreen.mainScreen().bounds.height, UIScreen.mainScreen().bounds.width)
            if maximumDim == 1024 { //iPad
                sourceRectX = x.x
            }else {
                sourceRectX = 0
            }

            rateDialog.popoverPresentationController?.sourceView = parent.view
            rateDialog.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection.allZeros
            rateDialog.popoverPresentationController?.sourceRect = CGRectMake(sourceRectX, x.y, 0, 0)
            rateDialog.popoverPresentationController?.popoverLayoutMargins = UIEdgeInsetsMake(0, 0, 0, 0)
            rateDialog.popoverPresentationController?.delegate = parent

            rateDialogParent = parent

            dispatch_async(dispatch_get_main_queue(), {
                parent.presentViewController(rateDialog, animated: true, completion: nil)
            })
            return true
        }
        return false
    }

Update: to achieve, point 3... on your parent UIViewController.

public class MyParentViewController: UIViewController, UIPopoverPresentationControllerDelegate {
    /**
    This function guarantees that the CustomDialog is always centered at parent, it locates the Dialog view
     */
    public func popoverPresentationController(popoverPresentationController: UIPopoverPresentationController, willRepositionPopoverToRect rect: UnsafeMutablePointer<CGRect>, inView view: AutoreleasingUnsafeMutablePointer<UIView?>) {
        let x = popoverPresentationController.presentingViewController.view.center
        let newRect = CGRectMake(x.x, x.y, 0, 0)
        rect.initialize(newRect)
    }

}