使用NFC打开网页

一、注册:

启动模式使用singleTask，避免每次打开新的activity

<activity
            android:name=".nfc.AutoOpenUriActivity"
            android:launchMode="singleTask">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
                <category android:name="android.intent.category.LAUNCHER" />
                />
            </intent-filter>
        </activity>

​

二、代码：

1、初始化NfcAdapter
2、在onresume时启动
mNfcAdapter.enableForegroundDispatch(this, mIntent, null, null);
3、在onpause时让其失效
mNfcAdapter.disableForegroundDispatch(this);
4、在onnewIntent时，获得Tag
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
然后写入数据
5、数据使用NdefMessage封装
6、通过tag获得ndef实现类，可以数据的写入数据
Ndef ndef = Ndef.get(tag);

package com.app.views.nfc;

import android.app.PendingIntent;
import android.content.Intent;
import android.net.Uri;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

import com.app.views.R;

import java.io.IOException;

public class AutoOpenUriActivity extends AppCompatActivity {

    private NfcAdapter mNfcAdapter;
    private PendingIntent mIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_auto_open_uri);
        mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
        mIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()), 0);
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (mNfcAdapter != null) {
            mNfcAdapter.enableForegroundDispatch(this, mIntent, null, null);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (mNfcAdapter != null) {
            mNfcAdapter.disableForegroundDispatch(this);
        }
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        writeNFCTag(tag);
    }

    private void writeNFCTag(Tag tag) {
        if (tag == null) return;
        NdefMessage msg = new NdefMessage(new NdefRecord[]{NdefRecord.createUri(Uri.parse("http://www.baidu.com"))});
        Ndef ndef = Ndef.get(tag);
        try {
            if (ndef != null) {
                ndef.connect();
                if (!ndef.isWritable()) return;
                if (ndef.getMaxSize() < msg.toByteArray().length) return;
                ndef.writeNdefMessage(msg);
                Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
            } else {
                NdefFormatable formatable = NdefFormatable.get(tag);
                if (formatable != null) {
                    formatable.connect();
                    formatable.format(msg);
                    Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(this, "format error", Toast.LENGTH_LONG).show();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (FormatException e) {
            e.printStackTrace();
        }
    }
}