Get UIAlertController action sheet width

Question

I have been banging my head a against the wall for a while now:

How can I get the width of a UIAlertController action sheet's view?

Saying alert.view.frame.width gives view.frame.width.

Also, I saw this question, but it simply does not work: it just changes the frame of the alert, and I don't see how I can get the width from it.

Thanks in advance.

Have a look here: http://stackoverflow.com/questions/40933616/ios-swift-3-uialertcontroller-width — ronatory, Mar 16 '17 at 21:28
@ronatory, I do not want to set the width, I just want to get it — IHaveAQuestion, Mar 16 '17 at 21:32
"`alert.view.frame.width` gives `view.frame.width`" – I'm getting the correct result, what do you mean with this statement? — xoudini, Mar 16 '17 at 21:46

score 1 · Accepted Answer · answered Mar 16 '17 at 21:54

1

The width of the .actionSheet type UIAlertController is the width of the UIWindow (in portrait mode) minus 10 points of padding on each side, irregardless of the device orientation.

E.g. in the case of an iPhone 7, which has a width of 375 points:

Unsurprisingly, 355 points is the same value I get from alert.view.frame.width, given that the value is accessed in the completion block of present(_:animated:completion:), i.e. after the view has appeared.

answered Mar 16 '17 at 21:54

xoudini

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When I call `alert.view.frame.width` before presenting `alert`, the width I get is 375. Why is this? – IHaveAQuestion Mar 16 '17 at 22:01
1

Also, it is different for iPad, so I need a not-hardcoded way to get the width – IHaveAQuestion Mar 16 '17 at 22:04
Because the view controller containing the view hasn't been presented yet. Why it's 375 and not 0, I'm not certain, but I believe it falls under what you may call "undocumented behaviour". – xoudini Mar 16 '17 at 22:04
@IHaveAQuestion What exactly do you need it for? Apparently it isn't enough for you to get the value from inside the completion block? – xoudini Mar 16 '17 at 22:07
I wanted to present a custom view within the alert – IHaveAQuestion Mar 16 '17 at 22:07
@IHaveAQuestion Why not use constraints then? – xoudini Mar 16 '17 at 22:08
Although I guess changing and maybe animating in the present completion block to the correct size is ok. Also I'm a little afraid of constraints. – IHaveAQuestion Mar 16 '17 at 22:09

score 0 · Answer 2 · edited May 23 '17 at 12:17

xoudini's Answer is definitely a solution. But a disadvantage could be the little delay of adding the custom view with the right width in the completion block. See the gif:

So an alternative solution could be, just to use this extension for UIDevice and then by checking the modelName, you can set the width values of the the action sheet of the different devices (maybe a little bit hacky, but you would avoid the delay and can set the width before the completion block). Here are the different width sizes of the action sheets of the currently supported devices of iOS10:

iPhone5/iPhone5s/iPhoneSE: 300
iPhone6/iPhone6s/iPhone7: 355
iPhone6Plus/iPhone6sPlus/iPhone7Plus: 394
iPad 9.7/12.9/Retina/Air1/Air2: 300

score -1 · Answer 3 · answered Jul 17 '17 at 17:47

Though I am late here, but better late than never.

Width for alert view controller is set in constraints. To get the width of the alert controller, you can use:

for constraint in self.alertView.subviews[0].constraints {

  if constraint.firstAttribute == NSLayoutAttribute.width {
  print("\(constraint.constant)")
  break
  }
}

Get UIAlertController action sheet width

3 Answers3