Question

尝试使用iPhone 7 Plus阅读NFC标签时出现此错误

2017-12-13 14：03：01.522137-0300 nfc [279：9534] [general]与名为com.apple.nfcd.service.corenfc的服务的连接：在解码收到的消息，丢弃传入消息时捕获异常。

异常：解码参数0（调用的＃2）时发生异常：

异常：decodeObjectForKey：类“NFTechnologyEvent”未加载或不存在

我拥有适当的权利（Near Field Communication Tag Reading）和Privacy - NFC Scan Usage Description已设置。

要重现它，只需启动一个新的单个视图项目，并用以下内容替换默认的ViewController：

import UIKit
import CoreNFC

class ViewController: UIViewController, NFCNDEFReaderSessionDelegate {
    // Reference the NFC session
    private var nfcSession: NFCNDEFReaderSession!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        self.startScanning()
    }

    func startScanning() {
        // Create the NFC Reader Session when the app starts
        self.nfcSession = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: false)

        // A custom description that helps users understand how they can use NFC reader mode in your app.
        self.nfcSession?.alertMessage = "Macri Gato"

        self.nfcSession?.begin()
    }

    // Called when the reader-session expired, you invalidated the dialog or accessed an invalidated session
    public func readerSession(_ session: NFCNDEFReaderSession, didInvalidateWithError error: Error) {
        print("NFC-Session invalidated: \(error.localizedDescription)")

        print("==========================")

        self.startScanning()
    }

    // Called when a new set of NDEF messages is found
    public func readerSession(_ session: NFCNDEFReaderSession, didDetectNDEFs messages: [NFCNDEFMessage]) {
        print("New NFC Messages (\(messages.count)) detected:")
        print(messages)
    }
}

Answer 1

在开始nfcSession之前，必须检查NFCNDEFReaderSession.readingAvailable true才能继续使用session.begin（）方法。

还要确保在Info.plist中添加“ 隐私-NFC扫描使用说明”

@IBAction func beginScanning(_ sender: Any) {
guard NFCNDEFReaderSession.readingAvailable else {
    let alertController = UIAlertController(
        title: "Scanning Not Supported",
        message: "This device doesn't support tag scanning.",
        preferredStyle: .alert
    )
    alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
    self.present(alertController, animated: true, completion: nil)
    return
}

session = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: false)
session?.alertMessage = "Hold your iPhone near the item to learn more about it."
session?.begin()

}

iOS CoreNFC - 未加载或不存在“NFTechnologyEvent”类

1 个答案: