如何在Android应用程序中全局读取NFC标签数据

Question

I would like to read the NFC tag data inside my application. Basically I have different NFC tags associated with different actions to perform inside my application. I know declaring the IntentFilter inside the Service is a bad idea. I don't want to associate this to any Activity .

Here is my manifest:

 <service android:name="com.yo.helpers.NFCReaderHelper"
        android:enabled="true"
        android:exported="true" >
        <intent-filter>
            <action android:name="android.nfc.action.NDEF_DISCOVERED" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:scheme="http" />
        </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>
 </service>

Here is my Service class:

@Override
protected void onHandleIntent(Intent intent) {
    Log.d("yoyo", "Service");
    Tag mTag = null;
    if(intent.getAction()!=null)
    {
        if(intent.getAction().equals("android.nfc.action.NDEF_DISCOVERED"))
            Log.d("yoyo", "Intent call");

        mTag = (Tag) intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        Log.i("tag ID", bytesToHexString(mTag.getId()));            
    }
}

I don't get the call inside the onHandleIntent method. If I do the same inside an Activity then I receive the intent inside the onNewIntent method.

Answer 1

You can't receive the NFC discovery intents ( NDEF_DISCOVERED , TECH_DISCOVERED , TAG_DISCOVERED ) with a service (or a broadcast receiver). NFC on Android is designed as a means of user interaction and, hence, these intents are only delivered to activities.

A trick that you could use is to use an invisible/transparent activity to handle the intent. See How to run android program without open the app?