tambykojak tambykojak - 4 months ago 117
iOS Question

How to get a value from NSValue in Swift?

Here's what I've tried so far

func onKeyboardRaise(notification: NSNotification) {
var notificationData = notification.userInfo
var duration = notificationData[UIKeyboardAnimationDurationUserInfoKey] as NSNumber
var frame = notificationData[UIKeyboardFrameBeginUserInfoKey]! as NSValue
var frameValue :UnsafePointer<(CGRect)> = nil;
frame.getValue(frameValue)
}


But I always seem to crash at
frame.getValue(frameValue)
.

It's a little bit confusing because the documentation for
UIKeyboardFrameBeginUserInfoKey
says it returns a
CGRect
object, but when I log
frame
in the console, it states something like
NSRect {{x, y}, {w, h}}
.

Answer

getValue() must be called with a pointer to an (initialized) variable of the appropriate size:

var frameValue = CGRect(x: 0, y: 0, width: 0, height: 0)
frame.getValue(&frameValue)

But it is simpler to use the convenience method:

let frameValue = frame.CGRectValue() // Swift 1, 2
let frameValue = frame.cgRectValue() // Swift 3