Question

我用Xamarin在c＃编码。我试图通过NFC将数据从一个设备共享到另一个设备。

打开浏览器 - ＆gt;选项 - ＆gt;分享 - ＆gt; App4到MainActivity

我的两个设备都运行相同的应用程序而我正在将设备点击到其他设备，但没有任何反应。

我认为它无法到达onNewIntent()。

我错过了什么吗？我很困惑，一直在寻找一周。

这是我的代码：

using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Nfc;
using System.Collections.Generic;
using System.Text;
using Xamarin.Forms;

namespace App4
{
    [Activity(Label = "App4", MainLauncher = false, Icon = "@drawable/icon",LaunchMode = Android.Content.PM.LaunchMode.SingleTop)]
    [IntentFilter(new[] { Intent.ActionSend , NfcAdapter.ActionNdefDiscovered }, Categories = new[] {
    Intent.CategoryDefault,
    Intent.CategoryBrowsable
    }, DataMimeType = "text/plain")]
    public class MainActivity : Activity
    {
        string share;
        PendingIntent mPendingIntent;
        IntentFilter ndefDetected;
        IntentFilter[] intentF;
        TextView testTV;
        protected override void OnCreate(Bundle bundle)
        {

            base.OnCreate(bundle);
            SetContentView(Resource.Layout.Main);  

            Intent Myintent = new Intent(this, GetType());
            Myintent.SetFlags(ActivityFlags.SingleTop);
            mPendingIntent = PendingIntent.GetActivity(this, 0, Myintent, 0);
            ndefDetected = new IntentFilter(NfcAdapter.ActionNdefDiscovered);
            try
            {
                ndefDetected.AddDataType("text/plain");
                ndefDetected.AddCategory(Intent.CategoryDefault);
            }
            catch { };

            intentF = new IntentFilter[] { ndefDetected };
            NfcAdapter NA = NfcAdapter.GetDefaultAdapter(this);   

            if (NA!=null && NA.IsEnabled)
            {
                Toast.MakeText(this, "Nfc Found", ToastLength.Long).Show();
            }else
            {
                Toast.MakeText(this, "Nfc Not Found", ToastLength.Long).Show();
            }
            testTV = FindViewById<TextView>(Resource.Id.text_view);
            share = Intent.GetStringExtra(Intent.ExtraText);  
            testTV.Text = share;   
    }

        protected override void OnPause()
        {
            base.OnPause();

            NfcManager manager = (NfcManager)GetSystemService(NfcService);
            NfcAdapter adapter = manager.DefaultAdapter;
            adapter.DisableForegroundNdefPush(this);
            adapter.DisableForegroundDispatch(this);
        }

        protected override void OnResume()
        {
            base.OnResume();


            var result2 = new byte[NdefRecord.RtdText.Count];
            NdefRecord.RtdUri.CopyTo(result2, 0);

            NfcManager manager = (NfcManager)GetSystemService(NfcService);
            NdefRecord record = new NdefRecord(NdefRecord.TnfAbsoluteUri,new byte[0], new byte[0], System.Text.Encoding.Default.GetBytes(share));
            manager.DefaultAdapter.EnableForegroundNdefPush(this, new NdefMessage(record));
            manager.DefaultAdapter.EnableForegroundDispatch(this, mPendingIntent, intentF, null);
        }

        protected override void OnNewIntent(Intent intent)
        {

            base.OnNewIntent(intent);
            testTV.Text = "onNewIntent";        
        }
    }
}

这是我的AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="App4.App4" android:versionCode="1" android:versionName="1.0" android:installLocation="auto">
    <uses-sdk android:minSdkVersion="10" />
    <uses-permission android:name="android.permission.NFC"></uses-permission>
    <application android:label="App4"></application>
</manifest>

Answer 1

是的，你遗漏了一些东西：你注册了前台调度来监听＃34; text / plain＆＃34;类型的NDEF消息，这意味着你要么想要一个文本记录，要么就是一个带有MIME类型文本的记录/纯

ndefDetected = new IntentFilter(NfcAdapter.ActionNdefDiscovered);
ndefDetected.AddDataType("text/plain");
ndefDetected.AddCategory(Intent.CategoryDefault);
intentF = new IntentFilter[] { ndefDetected };
manager.DefaultAdapter.EnableForegroundDispatch(this, mPendingIntent, intentF, null);

但是，您的应用会使用无效（空！）类型名称推送绝对URI记录。

NdefRecord record = new NdefRecord(NdefRecord.TnfAbsoluteUri,new byte[0], new byte[0], System.Text.Encoding.Default.GetBytes(share));
manager.DefaultAdapter.EnableForegroundNdefPush(this, new NdefMessage(record));

为了匹配意图过滤器，您需要改为推送文本记录：

byte[] text = System.Text.Encoding.UTF8.GetBytes(share);
byte[] language = System.Text.Encoding.ASCII.GetBytes("en");
byte[] payload = new byte[1 + language.Count + text.Count];
payload[0] = (byte)language.Count;
System.Array.Copy(language, 0, payload, 1, language.Count);
System.Array.Copy(text, 0, payload, 1 + language.Count, text.Count);
NdefRecord record = new NdefRecord(NdefRecord.TnfWellKnown, new List<byte>(NdefRecord.RtdText).ToArray(), new byte[0], payload);
manager.DefaultAdapter.EnableForegroundNdefPush(this, new NdefMessage(record));

在点击另一个支持NFC的设备后未调用onNewIntent

1 个答案: