我创建了一个UIAlertController
let alertC = UIAlertController(title: "Title",message: "Message",preferredStyle: UIAlertControllerStyle.Alert) alertC.addTextFieldWithConfigurationHandler(addTextField) alertC.addAction(UIAlertAction(title: "Cancel",style: UIAlertActionStyle.Default,handler: nil)) alertC.addAction(UIAlertAction(title: "OK",handler: okButton)) presentViewController(alertC,animated: true,completion: nil)
但之后我想改变UIAlertController的高度？我怎样才能做到这一点？
我发现在呈现视图控制器之前可以添加约束
let alertController = UIAlertController(title: nil,message: "hello",preferredStyle: .Alert)
let cancelAction = UIAlertAction(title: "Cancel",style: .Cancel) { (action) in
// hide action sheet
}
alertController.addAction(cancelAction)
var height:NSLayoutConstraint = NSLayoutConstraint(item: alertController.view,attribute: NSLayoutAttribute.Height,relatedBy: NSLayoutRelation.Equal,toItem: nil,attribute: NSLayoutAttribute.NotAnAttribute,multiplier: 1,constant: self.view.frame.height * 0.80)
alertController.view.addConstraint(height);
self.presentViewController(alertController,completion: nil)