Core NFC Payload Error

Question

I would like to scan the NDEF data from my NFC-Tag (NXP NTAG213) using the Core NFC framework introduced in iOS 11.

I succeeded to read the Payload within the tag:

TNF=1, Payload Type=<54>, Payload ID=<>, Payload=<026a61e3 8193e382 93e381ab e381a1e3 81af0a>

I'd like to extract the payload part, so here's what I've tried:

 print("payload.payload")

but error occurred.

Here's my source code:

import UIKit
import CoreNFC

class ViewController: UIViewController, NFCNDEFReaderSessionDelegate{

var payloadData = "HaveNoData"

func readerSession(_ session: NFCNDEFReaderSession, didDetectNDEFs messages: [NFCNDEFMessage]) {
    print("エラーは発生しませんでした")
    for message in messages{
        for payload in message.records {
            print (payload)
            payloadData = String(describing: payload.payload)
        }
    }
    print(payloadData)
}

func readerSession(_ session: NFCNDEFReaderSession, didInvalidateWithError error: Error) {
    print("Error: \(error.localizedDescription)")
}

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    let session:NFCNDEFReaderSession = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: true)

    session.begin()

}

@IBAction func launch(_ sender: Any) {
    let session:NFCNDEFReaderSession = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: true)
    session.begin()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

Answer 1

I'm not sure if you can use describing: on payload.payload here. But I believe the old-fashion String from NSData would work. (Not a daily Swift coder so not sure how it handles this these days with Swift 3/4).

In Objective-C, I can do it with:

NSString *dataString = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

or in your case NSUTF8StringEncoding for the Japanese string.

Here's a sample project I made (in Objective-C).