在 iOS 设备上使用 .NET MAUI 扫描 NFC 标签

问题描述 投票：0回答：1

我正在开发一个 .NET MAUI 应用程序，扫描 NFC 标签是要求之一。我已经完成了Android的开发，非常简单。对于 Android，从检测 NFC 标签、获取有效负载到处理有效负载，一切正常。

对于 iOS，我无法检测到 NFC 标签。这是我所做的。

iOS NFC 读卡器服务

我为 iOS 实现了一个非常简单的 NFC 服务，如下所示。

using CoreFoundation;
using CoreNFC;
using Foundation;
using MSS.App.Services.Interfaces;
using System;
using UIKit;

namespace OurAppNamespace.Platforms.iOS.Services
{
    public class IosNfcService : NFCTagReaderSessionDelegate, INfcService
    {
        private readonly ILogService? _logService;

        private NFCTagReaderSession? _nfcSession;

        public IosNfcService(ILogService? logService)
        {
            _logService = logService;
        }

        public async void Enable()
        {
            _logService?.LogInfo($"{this}.Enable");

            try
            {
                var isNfcAvailable = UIDevice.CurrentDevice.CheckSystemVersion(13, 0);

                _logService?.LogInfo($"{this}.Enable > {nameof(isNfcAvailable)} = {isNfcAvailable}");

                if (isNfcAvailable)
                {
                    _nfcSession = new NFCTagReaderSession(NFCPollingOption.Iso14443 | NFCPollingOption.Iso15693, this, DispatchQueue.CurrentQueue)
                    {
                        AlertMessage = "Test123"
                    };
                    _nfcSession.BeginSession();

                    _logService?.LogInfo($"{this}.Enable > Session started.");
                }
            }
            catch (Exception exception)
            {
                _logService?.LogError($"{this}.Enable > Starting Reader Session failed.", exception);
            }
        }

        public override void DidBecomeActive(NFCTagReaderSession session)
        {
            _logService?.LogInfo($"{this}.DidBecomeActive");
        }

        public override void DidInvalidate(NFCTagReaderSession session, NSError error)
        {
            _logService?.LogInfo($"{this}.DidInvalidate");
        }

        public override void DidDetectTags(NFCTagReaderSession session, INFCTag[] tags)
        {
            _logService?.LogInfo($"{this}.DidDetectTags");
        }

        public void Disable()
        {
            _logService?.LogInfo($"{this}.Disable");

            _nfcSession?.InvalidateSession();
        }
    }
}

它基于我在网上找到的几个代码示例。基本思想（据我了解）是，如果 iOS 版本为 13 或更高版本，则创建一个 NFCTagReaderSession 实例，只要打开视图就启动读取器会话，一旦检测到某些内容，就会调用适当的函数。根据我的理解，一旦我将手机放在 NFC 标签上，我应该会接到 

DidDetectTags
的电话 - 但我没有。

信息.plist

我已经编辑了 .NET MAUI 项目中 Platforms/iOS 下的 Info.plist，以添加 NFC 标签的权限。我添加到文件中的行是：

<key>NFCReaderUsageDescription</key>
<string>NFC tag to read NDEF messages into the application</string>
<key>com.apple.developer.nfc.readersession.iso7816.select-identifiers</key>
<array>
    <string>com.apple.developer.nfc.readersession.iso7816.select-identifiers</string>
    <string>D2760000850100</string>
</array>

权利.plist

这是我的第一个针对 iOS 的应用程序，我了解了 iOS 所需的权利。我按照官方指南的所有步骤进行操作。

  1. 我在 Platforms/iOS 下的 Info.plist 旁边的项目中添加了一个空的 Entitlements.plist 文件。
  2. 我打开项目的设置，转到“iOS”类别，然后转到“Bundle Signing”，并在“自定义权利”下添加刚刚添加的 Entitlements.plist。

这将以下文本添加到我的项目配置中。

<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net8.0-ios|AnyCPU'">
  <CodesignEntitlements>Platforms\iOS\Entitlements.plist</CodesignEntitlements>
</PropertyGroup>

<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net8.0-ios|AnyCPU'">
  <CodesignEntitlements>Platforms\iOS\Entitlements.plist</CodesignEntitlements>
</PropertyGroup>

结果

我已经删除了解决方案的 bin 和 obj 文件夹，从 iOS 设备中删除了之前部署的应用程序测试版本，重新启动了设备，然后重建了整个解决方案。如果我现在打开应用程序，我可以打开应用程序，但我没有收到任何 NFC 事件。我看到了 

Enable
函数的日志输出，但没有看到 
DidDetectTags
的调用。

我已经添加了Entitlements.plist，但我没有在文件中设置“近场通信标签读取”复选框。如果这样做，我将无法再启动该应用程序。 Visual Studio 的输出并没有告诉我太多信息，但 Xamarin 的日志文件表明配置文件存在问题。我研究了下面提到的错误，但我不确定如何继续。如果我从 Entitlements.plist 中删除复选框，应用程序将正常运行 - 但我没有检测到任何 NFC 标签。

Xamarin.Messaging.IDB.Local.DeployAppMessageHandler Error: 0 : An error occurred while trying to deploy the app '[APP_NAME]'. Details: Could not install the application '[PATH]\[APP_NAME]\out\[APP].ipa' on the device [TEST_DEVICE]. Details: ApplicationVerificationFailed|0xE8008015 - Failed to verify code signature of /var/installd/Library/Caches/com.apple.mobile.installd.staging/temp.59k3xO/extracted/Payload/[APP_NAME] : 0xe8008015 (A valid provisioning profile for this executable was not found.)
Xamarin.iOS.Windows.WindowsiOSException: Could not install the application '[LOCAL_PATH]\[APP_NAME]\out\[APP].ipa' on the device [TEST_DEVICE]. Details: ApplicationVerificationFailed|0xE8008015 - Failed to verify code signature of /var/installd/Library/Caches/com.apple.mobile.installd.staging/temp.59k3xO/extracted/Payload/[APP_NAME] : 0xe8008015 (A valid provisioning profile for this executable was not found.)
   at Xamarin.iOS.Windows.Installer.ApplicationSession.InstallApp(String appPath, String appBundleId) in D:\a\_work\1\s\src\Tools\Xamarin.iOS.Windows.Client\Installer\ApplicationSession.cs:line 276
   at Xamarin.iOS.Windows.Installer.ApplicationSession.Deploy(String appRootFolder, String appBundleId, String appName) in D:\a\_work\1\s\src\Tools\Xamarin.iOS.Windows.Client\Installer\ApplicationSession.cs:line 95
   at Xamarin.iOS.Windows.HotRestartClient.Deploy(AppleDevice nativeDevice, String appBundleId, String appBundleName, Boolean& incremental) in D:\a\_work\1\s\src\Tools\Xamarin.iOS.Windows.Client\HotRestartClient.cs:line 250
   at Xamarin.Messaging.IDB.Local.DeployAppMessageHandler.<ExecuteAsync>d__5.MoveNext() in D:\a\_work\1\s\src\Messaging\Xamarin.Messaging.IDB.Local\Handlers\DeployAppMessageHandler.cs:line 43: 04/04/2024 16:20:09Z
    DateTime=2024-04-04T16:20:09.7343180Z: 04/04/2024 16:20:09Z
ios maui nfc core-nfc
1个回答
0
投票

如果您在这里查看我的博客：https://medium.com/stackademic/nfc-ndef-communication-with-maui-and-xamarin-forms-fae28632c2d3

我已经展示了如何创建一个自定义会话来让您接收回调：

 public class SessionDelegate : NFCNdefReaderSessionDelegate
{
    private readonly byte[] bytes;
    public TaskCompletionSource<NfcTransmissionStatus> WasDataTransmitted { get; set; }

    public SessionDelegate(byte[] bytes)
    {
        this.bytes = bytes;
        WasDataTransmitted = new TaskCompletionSource<NfcTransmissionStatus>();
    }

    public override void DidDetect(NFCNdefReaderSession session, NFCNdefMessage[] messages)
    {

    }

    public override void DidDetectTags(NFCNdefReaderSession session, INFCNdefTag[] tags)
    {
        MainThread.BeginInvokeOnMainThread(() =>
        {
            session.AlertMessage = "Tag detected";
            try
            {
                if (tags.Length != 1)
                {
                    session.InvalidateSession(errorMessage: "Cannot write on multiple tags at the same time");
                    WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                    return;
                }
                var NdefTag = tags.First();
                session.ConnectToTag(NdefTag, (error) =>
                {
                    if (error != null)
                    {
                        WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                        session.InvalidateSession("There was an error while making this request");
                        return;
                    }
                });
                NdefTag?.QueryNdefStatus((status, capacity, error) =>
                {
                    if (error != null)
                    {
                        WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                        session.InvalidateSession("Could not query status of tag");
                    }
                    switch (status)
                    {
                        case NFCNdefStatus.NotSupported:
                            WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                            session.InvalidateSession("This is an unsupported tag");
                            break;
                        case NFCNdefStatus.ReadOnly:
                            WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                            session.InvalidateSession("This tag is readonly");
                            break;
                        case NFCNdefStatus.ReadWrite:
                            var isNfcWriteAvailable = UIDevice.CurrentDevice.CheckSystemVersion(13, 0);
                            if (isNfcWriteAvailable)
                            {
                                var chunkString = Encoding.UTF8.GetString(bytes);
                                var textPayload = NFCNdefPayload.CreateWellKnownTypePayload(chunkString);
                                var ndefpayloadArray = new NFCNdefPayload[] { textPayload };
                                var ndefMessage = new NFCNdefMessage(ndefpayloadArray);
                                NdefTag.WriteNdef(ndefMessage, (tagError) =>
                                {
                                    if (tagError != null)
                                    {
                                        WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                                        session.InvalidateSession("Falied to write this message");
                                    }
                                    else
                                    {
                                        session.AlertMessage = "Write successful";
                                        session.InvalidateSession();
                                        WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Success);
                                    }
                                });
                            }
                            else
                            {
                                WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
                                session.InvalidateSession("There was an error while trying to write on this tag");
                            }
                            break;
                        default:
                            WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Unknown);
                            session.InvalidateSession("Tag status unkoown");
                            break;
                    }
                });
            }
            catch
            {
                session.InvalidateSession();
                WasDataTransmitted.TrySetResult(NfcTransmissionStatus.Failed);
            }
        });
    }

    public override void DidInvalidate(NFCNdefReaderSession session, NSError error)
    {
        if (error.Code == (int)NFCReaderError.ReaderSessionInvalidationErrorSessionTimeout)
        {
            MainThread.BeginInvokeOnMainThread(async () =>
            {
                await Application.Current.MainPage.DisplayAlert("Error ", "Tag search timed out", "Ok");
            });
        }
    }
}

然后将其与 TaskCompletionSource 一起使用，您应该能够获得回调。

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