Android如何实现NFC读取卡片信息

    <!--    API 级别 9 仅通过  所以最低是10版本-->
    <uses-sdk android:minSdkVersion="10" />
    <!--    NFC 权限  -->
    <uses-permission android:name="android.permission.NFC" />
    <!--    以便您的应用仅在那些具备 NFC 硬件的设备的 Google Play 中显示：-->
    <uses-feature
        android:name="android.hardware.nfc"
        android:required="true" />

        <!--NFC启动的页面 -->
        <activity android:name=".NFCActivity">
            <!--  配置过滤启动类型-->
            <intent-filter>
                <action android:name="android.nfc.action.TECH_DISCOVERED" />
            </intent-filter>
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech_filter" />
 
            <!--            <intent-filter>-->
            <!--                <action android:name="android.nfc.action.NDEF_DISCOVERED"/>-->
            <!--                <category android:name="android.intent.category.DEFAULT"/>-->
            <!--                <data android:scheme="http"-->
            <!--                    android:host="developer.android.com"-->
            <!--                    android:pathPrefix="/index.html" />-->
            <!--            </intent-filter>-->
 
            <!--            <intent-filter>-->
            <!--                <action android:name="android.nfc.action.NDEF_DISCOVERED"/>-->
            <!--                <category android:name="android.intent.category.DEFAULT"/>-->
            <!--                <data android:mimeType="text/plain" />-->
            <!--            </intent-filter>-->
 
        </activity>

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
    <!-- 可以处理所有Android支持的NFC类型 -->
    <tech-list>
        <tech>android.nfc.tech.IsoDep</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NfcA</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NfcB</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NfcF</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NfcV</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.Ndef</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NdefFormatable</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.MifareUltralight</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.MifareClassic</tech>
    </tech-list>
</resources>

import android.content.Intent
import android.nfc.NdefMessage
import android.nfc.NdefRecord.createMime
import android.nfc.NfcAdapter
import android.nfc.NfcEvent
import android.nfc.Tag
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.DataBindingUtil
import com.wkq.nfc.databinding.ActivityMainBinding
 
/**
 * NFC 拉起页面
 */
class NFCActivity : AppCompatActivity(), NfcAdapter.CreateNdefMessageCallback {
 
    //支持的标签类型
    private var nfcAdapter: NfcAdapter? = null
    private var binding: ActivityMainBinding? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
        nfcAdapter = NfcAdapter.getDefaultAdapter(this)
        if (nfcAdapter==null){
            Toast.makeText(this, "该机型不支持NFC", Toast.LENGTH_LONG).show()   
            finish()
        }
        // Register callback  *设置一个回调，使用Android Beam（TM）动态生成要发送的NDEF消息。
        nfcAdapter?.setNdefPushMessageCallback(this, this)
    }
 
 
    override fun onResume() {
        super.onResume()
        // Check to see that the Activity started due to an Android Beam
        if (NfcAdapter.ACTION_TECH_DISCOVERED == intent.action) {
            processIntent(intent)
        }
    }
 
    override fun onPause() {
        super.onPause()
        nfcAdapter!!.disableReaderMode(this)
    }
 
    override fun onNewIntent(intent: Intent?) {
        super.onNewIntent(intent)
        setIntent(intent)
    }
 
    /**
     * 处理Intent携带的数据
     */
    private fun processIntent(intent: Intent) {
        // 处理北京公交卡的数据
        var tag = intent.extras
        if (tag==null)return
  
        var content = NFCUtil.bytesToHex((tag!!.get("android.nfc.extra.TAG") as Tag).id)
        binding?.tvContent!!.text = content
        Toast.makeText(this, "获取北京地铁卡数据:" + content, Toast.LENGTH_LONG).show()
    }
 
    override fun createNdefMessage(event: NfcEvent?): NdefMessage {
        val text = "Beam me up, Android!\n\n" +
                "Beam Time: " + System.currentTimeMillis()
        return NdefMessage(
            arrayOf(
                createMime("application/vnd.com.example.android.beam", text.toByteArray())
            )
        )
 
    }
}