如何将布尔值转换为 NSData

Question

I found this post to convert a Int into NSData

It says to do this:

var foo: Int = 1000
let data = NSData(bytes: &foo, length: sizeof(Int))

I was wondering, should I do the same think for converting a Bool to NSData , like this:

 var purchase: Bool = true
 let data = NSData(bytes: &purchase, length: sizeof(Bool))

In my case I always know that the Bool will be true. Since this is the case, I was wondering if there is a simpler method to convert the value "true" to a NSData object.

Some background context:

I am storing this NSData value in the keychain with this library .

I am also going to be convert the NSData value back into a bool with NSKeyedUnarchiver.unarchiveObjectWithData

Answer 1

Swift 4 Solution

if let isBool = value as? Bool
{
    var valueInInt = Int(NSNumber(value: isBool)) //Convert Bool to Int
    let data = Data(bytes: &valueInInt, count: MemoryLayout.size(ofValue: valueInInt) //Int to Data
}

Answer 2

Swift >= 4 Solution

we can easily achieve this using JSONEncoder cause Bool struct confirms Codable Typealias

let mBoolValue = true
let boolData = try! JSONEncoder().encode(mBoolValue)

Answer 3

You can try extending Bool with a function that returns NSData

(I don't have my IDE with me right now, so the syntax might not be right)

extension Bool {
  func toNSData() -> NSData {
    var data: NSData?
    if ( self.value ) { //not sure if this is the right syntax
      return NSData(bytes: 1, length: sizeof(Int))
    }
    return NSData(bytes: 0, lentgh: sizeOf(Int))
  }
}

Then any bool will have NSData representation like so

let b: Bool = true
let data: NSData = b.toNSData()

I'm still new at this, but I think the above is part of "protocol oriented programming" that apple encourages.