swift playground UITextField spawns keyboard that is too big

I face the same issue. It seems as if Playground has a hard-coded screen size of 768x1024 (run UIScreen.main.bounds in the Playground) and shows the keyboard according to this size, independently of the live view's actual size.

The best workaround I came up with is to increase the size of the view controller so that it matches the keyboard:

let vc = TesterViewController()
vc.preferredContentSize = vc.view.frame.size // or a custom CGSize
PlaygroundPage.current.liveView = vc

Of course this makes the view larger than you might want it to be, so I only use this workaround when I really have to access the on-screen keyboard for testing.

System keyboard is presented according to the key window size and in the case of a playground simulator the size is 768x1024. It looks like it is a bug.

A solution which works:

Instead of passing a view controller one should pass a window with a custom size.

let window = UIWindow(frame: CGRect(x: 0,
                                    y: 0,
                                    width: 768,
                                    height: 1024))
let viewController = MyViewController()
window.rootViewController = viewController
window.makeKeyAndVisible()

PlaygroundPage.current.liveView = window

Works in Xcode 11 and above (latest tested version Xcode 12.2)

Edited

I have checked the answer which suggests to use "vc.preferredContentSize" but it doesn't work for me. Tested in Xcode 12.2

let vc = TextFieldViewController()
vc.preferredContentSize = CGSize(width: 768,height: 1024)
PlaygroundPage.current.liveView = vc