How can I convert my device token (NSData) into an

Question

I am implementing push notifications. I'd like to save my APNS Token as a String.

- (void)application:(UIApplication *)application
didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)newDeviceToken
{
    NSString *tokenString = [NSString stringWithUTF8String:[newDeviceToken bytes]]; //[[NSString alloc]initWithData:newDeviceToken encoding:NSUTF8StringEncoding];
    NSLog(@"%@", tokenString);
    NSLog(@"%@", newDeviceToken);
}

The first line of code prints null. the second prints the token. How can I get my newDeviceToken as an NSString?

Answer 1

For Swift :

var characterSet: NSCharacterSet = NSCharacterSet( charactersInString: "<>" )
    var deviceTokenString: String = ( deviceToken.description as NSString )
    .stringByTrimmingCharactersInSet( characterSet )
    .stringByReplacingOccurrencesOfString( " ", withString: "" ) as String

println( deviceTokenString )

Answer 2

-(NSString *)deviceTokenWithData:(NSData *)data
{
    NSString *deviceToken = [[data description] stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]];
    deviceToken = [deviceToken stringByReplacingOccurrencesOfString:@" " withString:@""];
    return deviceToken;
}

Answer 3

Swift 3:

If any one is looking for a way to get device token in Swift 3. Use the below modified snippet.

    let characterSet: CharacterSet = CharacterSet( charactersIn: "<>" )

    let deviceTokenString: String = (deviceToken.description as NSString)
        .trimmingCharacters(in: characterSet as CharacterSet)
        .replacingOccurrences(of: " ", with: "")
        .uppercased()

    print(deviceTokenString)

Answer 4

I've tried to test two different methods with format "%02.2hhx" and "%02x"

    var i :Int = 0
    var j: Int = 0
    let e: Int = Int(1e4)
    let time = NSDate.timeIntervalSinceReferenceDate
    while i < e {
        _ =  deviceToken.map { String(format: "%02x", $0) }.joined()
        i += 1
    }
    let time2 = NSDate.timeIntervalSinceReferenceDate
    let delta = time2-time
    print(delta)

    let time3 = NSDate.timeIntervalSinceReferenceDate
    while j < e {
        _ =  deviceToken.reduce("", {$0 + String(format: "%02x", $1)})
        j += 1
    }
    let time4 = NSDate.timeIntervalSinceReferenceDate
    let delta2 = time4-time3
    print(delta2)

and the result is that the fastest is "%02x" at average 2.0 vs 2.6 for the reduced version:

deviceToken.reduce("", {$0 + String(format: "%02x", $1)})

Answer 5

If anyone is looking for a way to do this in Swift:

func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
    let tokenChars = UnsafePointer<CChar>(deviceToken.bytes)
    var tokenString = ""

    for i in 0..<deviceToken.length {
        tokenString += String(format: "%02.2hhx", arguments: [tokenChars[i]])
    }

    print("tokenString: \(tokenString)")
}

Edit: For Swift 3

Swift 3 introduces the Data type, with value semantics. To convert the deviceToken to a String, you can do as follows:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    let token = deviceToken.map { String(format: "%02.2hhx", $0) }.joined()
    print(token)
}

Answer 6

You could use this

- (NSString *)stringWithDeviceToken:(NSData *)deviceToken {
    const char *data = [deviceToken bytes];
    NSMutableString *token = [NSMutableString string];

    for (NSUInteger i = 0; i < [deviceToken length]; i++) {
        [token appendFormat:@"%02.2hhX", data[i]];
    }

    return [token copy];
}