ios - How to add a simple button in a ViewController? -

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i have following code.

import uikit  class viewcontroller: uiviewcontroller {      var button : uibutton?      override func viewdidload() {         super.viewdidload()          button = uibutton.buttonwithtype(uibuttontype.system) uibutton?     }      override func didreceivememorywarning() {         super.didreceivememorywarning()         // dispose of resources can recreated.     }  }

i following error

error:

'anyobject' not convertible 'uibutton?'

i know might doing fundamentally wrong. know is.

according me: have declared button optional uibutton - think means, value of button can unset or nil

therefore, while initialising type mentioned as uibutton?

is right way ?

you can't cast optional uibutton in way you're doing it. correct way cast optional uibutton is:

button = uibutton.buttonwithtype(uibuttontype.system) as? uibutton

interpret as: cast can either return nil or uibutton object, resulting in optional uibutton object.


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