Cannot subscript a value of type [String: AnyObject]? with an index of type String

问题

I know have many the same question but still cannot find the way to fix my error. Please see the image for more detail. I used Xcode 7 and swift 2.0

Edit: fcking the warning of Swift. finnaly (change?[NSKeyValueChangeNewKey]?.boolValue)! fixed the error

回答1:

change is an optional. Either unwrap the optional

let isCaptureStillImage = change![NSKeyValueChangeNewKey]!.boolValue

or use optional bindings

if let changeNewKey = change?[NSKeyValueChangeNewKey] {
  let isCaptureStillImage = changeNewKey.boolValue

...

来源：https://stackoverflow.com/questions/32711613/cannot-subscript-a-value-of-type-string-anyobject-with-an-index-of-type-stri