Swift - IOS：UIalertController的位置

Question

我正在尝试创建一个自定义alertView，但我遇到了Alert的大小问题，所以我的问题是：我怎么知道左角的X位置和右角的x位置？

Answer 1

You can access properties on the frame of the view. alertView.frame.minX will get you the left corner X and alertView.frame.maxX will get you the right corner X.

Answer 2

You can get x position something like,

  x = self.view.frame.size.width/2.0 - yourCustomAlertView.frame.size.width/ 2.0

and same for y also,

  y = self.view.frame.size.height/2.0 - yourCustomAlertView.frame.size.height/ 2.0

Update : (As Asked in comment)

You can add width constraint same as you have added height constraint so your code will be look like,

    var height:NSLayoutConstraint = NSLayoutConstraint(item: alertController.view, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 200);

    var width : NSLayoutConstraint = NSLayoutConstraint(item: alertController.view, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 300);

    alertController.view.addConstraint(height);

     alertController.view.addConstraint(width);