bh006- Blazor hybrid / Maui 使用NFC快速教程
1. 建立工程 bh006_NFC_tag
2. 添加 nuget 包
<PackageReference Include="BlazorHybrid.Maui.Permissions" Version="0.0.3" />
<PackageReference Include="BootstrapBlazor" Version="7.*" />
<PackageReference Include="Densen.Extensions.BootstrapBlazor" Version="7.*" />
BlazorHybrid.Maui.Permissions 因为源码比较长,主要是一些检查和申请权限,BLE/NFC权限相关代码,就不占用篇幅列出,感兴趣的同学直接打开源码参考
顺便打开可空 <Nullable>enable</Nullable>
3. 添加蓝牙权限
安卓
Platforms\Android 文件夹
AndroidManifest.xml
<uses-permission android:name="android.permission.NFC" />
<uses-feature android:name="android.hardware.nfc" android:required="false" />
添加安卓必要Intent
MainActivity.cs
using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.Nfc;
using Android.OS;
using DH.NFC;
namespace bh006_NFC_tag
{
[Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize | ConfigChanges.Density)]
[IntentFilter(new[] { NfcAdapter.ActionNdefDiscovered }, Categories = new[] { Intent.CategoryDefault }, DataMimeType = NfcPage.MIME_TYPE)]
[IntentFilter(new[] { Platform.Intent.ActionAppAction },
Categories = new[] { global::Android.Content.Intent.CategoryDefault })]
public class MainActivity : MauiAppCompatActivity
{
protected override void OnCreate(Bundle savedInstanceState)
{
// 初始化
CrossNFC.Init(this);
base.OnCreate(savedInstanceState);
}
protected override void OnResume()
{
base.OnResume();
// 恢复时重新启动NFC监听（Android 10+需要）
CrossNFC.OnResume();
}
protected override void OnNewIntent(Intent intent)
{
base.OnNewIntent(intent);
// 标签发现拦截
CrossNFC.OnNewIntent(intent);
//AppActions
Platform.OnNewIntent(intent);
}
}
}
iOS
Platforms\iOS 文件夹
Info.plist
<key>NFCReaderUsageDescription</key>
<string>此应用程序需要NFC标签读取NDEF消息到应用程序中,请根据要求授予权限.</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>
新建 Entitlements.plist 文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>com.apple.developer.nfc.readersession.formats</key>
<array>
<string>NDEF</string>
<string>TAG</string>
</array>
</dict>
</plist>
iOS开发者应用注册清单添加必要权限, (传送门)[]
4. 添加 BootstrapBlazor UI 库请参考前几篇
5. 添加代码后置文件 Pages/Index.razor.cs
Index.razor.cs
using BootstrapBlazor.Components;
using DH.NFC;
using Microsoft.AspNetCore.Components;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Text;
namespace bh006_NFC_tag.Pages;
public partial class Index : IAsyncDisposable
{
[Inject, NotNull] protected MessageService? MessageService { get; set; }
[NotNull]
protected Message? Message { get; set; }
[DisplayName("使标签为只读")]
bool ChkReadOnly { get; set; } = false;
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (firstRender)
{
// 为了支持Mifare Classic 1K标签（读/写），必须将传统模式设置为true。
CrossNFC.Legacy = false;
if (CrossNFC.IsSupported)
{
if (!CrossNFC.Current.IsAvailable)
await ShowAlert("NFC is not available");
NfcIsEnabled = CrossNFC.Current.IsEnabled;
if (!NfcIsEnabled)
await ShowAlert("NFC is disabled");
if (DeviceInfo.Platform == DevicePlatform.iOS)
_isDeviceiOS = true;
await AutoStartAsync().ConfigureAwait(false);
}
}
}
//连接外设
private async Task XamlPage()
{
MauiProgram.OpenNFCXamlPage();
//异步更新UI
await InvokeAsync(StateHasChanged);
}
async ValueTask IAsyncDisposable.DisposeAsync()
{
await StopListening();
}
public const string ALERT_TITLE = "NFC";
public const string MIME_TYPE = "application/com.densen.nfc";
NFCNdefTypeFormat _type;
bool _makeReadOnly = false;
bool _eventsAlreadySubscribed = false;
bool _isDeviceiOS = false;
//https://gitee.com/dengho/DH.Maui.FrameWork/blob/master/Demo/DH.NFCDemo/NfcPage.xaml.cs
/// <summary>
/// 跟踪Android设备是否仍在监听的属性，
/// 因此它可以向用户指示这一点。
/// </summary>
public bool DeviceIsListening
{
get => _deviceIsListening;
set
{
_deviceIsListening = value;
StateHasChanged();
}
}
private bool _deviceIsListening;
private bool _nfcIsEnabled;
public bool NfcIsEnabled
{
get => _nfcIsEnabled;
set
{
_nfcIsEnabled = value;
StateHasChanged();
}
}
public bool NfcIsDisabled => !NfcIsEnabled;
/// <summary>
/// 自动开始收听
/// </summary>
/// <returns></returns>
async Task AutoStartAsync()
{
// 在Android上阻止Java.Lang.IllegalStateException的一些延迟“仅当您的活动恢复时才能启用前台调度”
await Task.Delay(500);
await StartListeningIfNotiOS();
}
/// <summary>
/// 订阅NFC活动
/// </summary>
void SubscribeEvents()
{
if (_eventsAlreadySubscribed)
UnsubscribeEvents();
_eventsAlreadySubscribed = true;
CrossNFC.Current.OnMessageReceived += Current_OnMessageReceived;
CrossNFC.Current.OnMessagePublished += Current_OnMessagePublished;
CrossNFC.Current.OnTagDiscovered += Current_OnTagDiscovered;
CrossNFC.Current.OnNfcStatusChanged += Current_OnNfcStatusChanged;
CrossNFC.Current.OnTagListeningStatusChanged += Current_OnTagListeningStatusChanged;
if (_isDeviceiOS)
CrossNFC.Current.OniOSReadingSessionCancelled += Current_OniOSReadingSessionCancelled;
}
/// <summary>
/// 取消订阅NFC活动
/// </summary>
void UnsubscribeEvents()
{
CrossNFC.Current.OnMessageReceived -= Current_OnMessageReceived;
CrossNFC.Current.OnMessagePublished -= Current_OnMessagePublished;
CrossNFC.Current.OnTagDiscovered -= Current_OnTagDiscovered;
CrossNFC.Current.OnNfcStatusChanged -= Current_OnNfcStatusChanged;
CrossNFC.Current.OnTagListeningStatusChanged -= Current_OnTagListeningStatusChanged;
if (_isDeviceiOS)
CrossNFC.Current.OniOSReadingSessionCancelled -= Current_OniOSReadingSessionCancelled;
_eventsAlreadySubscribed = false;
}
/// <summary>
/// 侦听器状态更改时引发的事件
/// </summary>
/// <param name="isListening"></param>
void Current_OnTagListeningStatusChanged(bool isListening) => DeviceIsListening = isListening;
/// <summary>
/// NFC状态更改时引发的事件
/// </summary>
/// <param name="isEnabled">NFC status</param>
async void Current_OnNfcStatusChanged(bool isEnabled)
{
NfcIsEnabled = isEnabled;
await ShowAlert($"NFC has been {(isEnabled ? "enabled" : "disabled")}");
}
/// <summary>
/// 收到NDEF消息时引发的事件
/// </summary>
/// <param name="tagInfo">Received <see cref="ITagInfo"/></param>
async void Current_OnMessageReceived(ITagInfo tagInfo)
{
if (tagInfo == null)
{
await ShowAlert("No tag found");
return;
}
// 自定义序列号
var identifier = tagInfo.Identifier;
var serialNumber = NFCUtils.ByteArrayToHexString(identifier, ":");
var title = !string.IsNullOrWhiteSpace(serialNumber) ? $"标签 [{serialNumber}]" : "标签信息";
if (!tagInfo.IsSupported)
{
await ShowAlert("Unsupported tag (app)", title);
}
else if (tagInfo.IsEmpty)
{
await ShowAlert("Empty tag", title);
}
else
{
var first = tagInfo.Records[0];
await ShowAlert(GetMessage(first), title);
}
}
/// <summary>
/// Event raised when user cancelled NFC session on iOS
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void Current_OniOSReadingSessionCancelled(object? sender, EventArgs e) => Debug("iOS NFC Session has been cancelled");
/// <summary>
/// 在标记上发布数据时引发的事件
/// </summary>
/// <param name="tagInfo">发布<see cref="ITagInfo"/></param>
async void Current_OnMessagePublished(ITagInfo tagInfo)
{
try
{
ChkReadOnly = false;
CrossNFC.Current.StopPublishing();
if (tagInfo.IsEmpty)
await ShowAlert("Formatting tag operation successful");
else
await ShowAlert("Writing tag operation successful");
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
}
/// <summary>
/// 发现NFC标签时引发的事件
/// </summary>
/// <param name="tagInfo"><see cref="ITagInfo"/>被发布</param>
/// <param name="format">设置标签格式</param>
async void Current_OnTagDiscovered(ITagInfo tagInfo, bool format)
{
if (!CrossNFC.Current.IsWritingTagSupported)
{
await ShowAlert("此设备不支持写入标签");
return;
}
try
{
NFCNdefRecord? record = null;
switch (_type)
{
case NFCNdefTypeFormat.WellKnown:
record = new NFCNdefRecord
{
TypeFormat = NFCNdefTypeFormat.WellKnown,
MimeType = MIME_TYPE,
Payload = NFCUtils.EncodeToByteArray("DH.Maui.FrameWork是很棒的!"),
LanguageCode = "en"
};
break;
case NFCNdefTypeFormat.Uri:
record = new NFCNdefRecord
{
TypeFormat = NFCNdefTypeFormat.Uri,
Payload = NFCUtils.EncodeToByteArray("https://gitee.com/dengho/DH.Maui.FrameWork")
};
break;
case NFCNdefTypeFormat.Mime:
record = new NFCNdefRecord
{
TypeFormat = NFCNdefTypeFormat.Mime,
MimeType = MIME_TYPE,
Payload = NFCUtils.EncodeToByteArray("DH.Maui.FrameWork是很棒的!")
};
break;
default:
break;
}
if (!format && record == null)
throw new Exception("记录不能为空.");
tagInfo.Records = new[] { record };
if (format)
CrossNFC.Current.ClearMessage(tagInfo);
else
{
CrossNFC.Current.PublishMessage(tagInfo, _makeReadOnly);
}
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
}
/// <summary>
/// 当将引发<see cref="Current_OnTagDiscovered(ITagInfo, bool)"/>事件时，启动发布操作以写入文本标签
/// </summary>
async Task Button_Clicked_StartWriting() => await Publish(NFCNdefTypeFormat.WellKnown);
/// <summary>
/// 当将引发<see cref="Current_OnTagDiscovered(ITagInfo, bool)"/>事件时，启动发布操作以写入URI标签
/// </summary>
async Task Button_Clicked_StartWriting_Uri() => await Publish(NFCNdefTypeFormat.Uri);
/// <summary>
/// 当将引发<see cref="Current_OnTagDiscovered(ITagInfo, bool)"/>事件时，启动发布操作以写入自定义标签
/// </summary>
async Task Button_Clicked_StartWriting_Custom() => await Publish(NFCNdefTypeFormat.Mime);
/// <summary>
/// 当将引发<see cref="Current_OnTagDiscovered(ITagInfo, bool)"/>事件时，启动发布操作以格式化标签
/// </summary>
async Task Button_Clicked_FormatTag() => await Publish();
/// <summary>
/// 将数据发布到标签的任务
/// </summary>
/// <param name="type"><see cref="NFCNdefTypeFormat"/></param>
/// <returns>要执行的任务</returns>
async Task Publish(NFCNdefTypeFormat? type = null)
{
await StartListeningIfNotiOS();
try
{
_type = NFCNdefTypeFormat.Empty;
if (ChkReadOnly)
{
//if (!await DisplayAlert("警告", "使标签为只读操作是永久性的，无法撤消。您确定要继续吗？", "是", "否"))
//{
// ChkReadOnly = false;
// return;
//}
_makeReadOnly = true;
}
else
_makeReadOnly = false;
if (type.HasValue) _type = type.Value;
CrossNFC.Current.StartPublishing(!type.HasValue);
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
}
/// <summary>
/// 返回NDEF记录中的标记信息
/// </summary>
/// <param name="record"><see cref="NFCNdefRecord"/></param>
/// <returns>标签信息</returns>
string GetMessage(NFCNdefRecord record)
{
var message = $"消息: {record.Message}";
message += Environment.NewLine;
message += $"原始消息: {Encoding.UTF8.GetString(record.Payload)}";
message += Environment.NewLine;
message += $"类型: {record.TypeFormat}";
if (!string.IsNullOrWhiteSpace(record.MimeType))
{
message += Environment.NewLine;
message += $"Mime类型: {record.MimeType}";
}
return message;
}
/// <summary>
/// 在调试控制台中编写调试消息
/// </summary>
/// <param name="message">要显示的消息</param>
void Debug(string message) => System.Diagnostics.Debug.WriteLine(message);
/// <summary>
/// 显示消息
/// </summary>
/// <param name="message">要显示的消息</param>
/// <param name="title">消息标题</param>
/// <returns>要执行的任务</returns>
async Task ShowAlert(string message, string? title = null) =>
await MessageService.Show(new MessageOption()
{
Content = message,
Icon = "fa-solid fa-circle-info",
}, Message);
/// <summary>
/// 如果用户的设备平台不是iOS，则开始监听NFC标签的任务
/// </summary>
/// <returns>要执行的任务</returns>
async Task StartListeningIfNotiOS()
{
if (_isDeviceiOS)
{
SubscribeEvents();
return;
}
await BeginListening();
}
/// <summary>
/// 安全开始监听NFC标签的任务
/// </summary>
/// <returns>要执行的任务</returns>
async Task BeginListening()
{
try
{
MainThread.BeginInvokeOnMainThread(() =>
{
SubscribeEvents();
CrossNFC.Current.StartListening();
});
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
}
/// <summary>
/// 安全停止监听NFC标签的任务
/// </summary>
/// <returns>要执行的任务</returns>
async Task StopListening()
{
try
{
MainThread.BeginInvokeOnMainThread(async () =>
{
try
{
CrossNFC.Current.StopListening();
UnsubscribeEvents();
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
});
}
catch (Exception ex)
{
await ShowAlert(ex.Message);
}
}
}
6. 添加 UI Pages/Index.razor
Index.razor
@page "/"
<h3>NFC</h3>
<div class="row g-3">
<Button OnClick="BeginListening"
IsDisabled="NfcIsDisabled"
Text="读取标签" />
<Button OnClick="StopListening"
IsDisabled="NfcIsDisabled"
Text="停止侦听器" />
<GroupBox Title="写入">
@*<CheckBox TValue="bool" DisplayText="双向绑定" ShowLabel="true" @bind-value="@ChkReadOnly" IsDisabled="NfcIsDisabled" />*@
<Button OnClick="Button_Clicked_StartWriting"
IsDisabled="NfcIsDisabled"
Text="标签写入文本" />
<Button OnClick="Button_Clicked_StartWriting_Uri"
IsDisabled="NfcIsDisabled"
Text="标签写入网址" />
<Button OnClick="Button_Clicked_StartWriting_Custom"
IsDisabled="NfcIsDisabled"
Text="标签写入自定义内容" />
</GroupBox>
<Button OnClick="Button_Clicked_FormatTag"
IsDisabled="NfcIsDisabled"
Text="标签清除" />
@if (DeviceIsListening)
{
<p>监听NFC标签...</p>
}
@if (NfcIsDisabled)
{
<p>NFC已禁用</p>
}
<div class="btn-group" role="group">
<Button Text="NFC XAML" OnClick=XamlPage />
</div>
</div>
<pre style="max-height: 500px; overflow-y: scroll; white-space: pre-wrap; word-wrap: break-word;">@Message</pre>
10. 运行
11. 相关资料
如何远程调试 MAUI blazor / Blazor Hybrid
https://www.cnblogs.com/densen2014/p/16988516.html
关联项目
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Maui Blazor 中文社区 QQ群：645660665
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转载声明
本文来自博客园，作者：周创琳 AlexChow，转载请注明原文链接：https://www.cnblogs.com/densen2014/p/17653114.html
AlexChow
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