Friday, October 9, 2015

Android NFC example, to read tag info of RFID key and card


A simple Android example to read info of RFID tag (key and card in this demo) using NFC.

Edit src/main/AndroidManifest.xml to add <intent-filter> with action of "android.nfc.action.TAG_DISCOVERED" and category of "android.intent.category.DEFAULT", such that the app will be started when RFID tag place near NFC; if no other apps registered.

And add <uses-permission> of "android.permission.NFC", and <uses-feature> of "android.hardware.nfc"

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.blogspot.android_er.androidnfctagdiscovered" >

    <uses-permission android:name="android.permission.NFC"/>
    <uses-feature android:name="android.hardware.nfc"
        android:required="true"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" >
        <activity android:name=".MainActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.nfc.action.TAG_DISCOVERED"/>
                <category android:name="android.intent.category.DEFAULT"/>
            </intent-filter>
        </activity>
    </application>

</manifest>


In MainActivity.java:

In onCreate():
Create NfcAdapter object by calling NfcAdapter.getDefaultAdapter(this). And check if NFC supported and enabled.

Override onResume():
Check if intent is ACTION_TAG_DISCOVERED. if yes, we can obtain a Tag object from the intent, by calling intent.getParcelableExtra(NfcAdapter.EXTRA_TAG).

package com.blogspot.android_er.androidnfctagdiscovered;

import android.content.Intent;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private NfcAdapter nfcAdapter;
    TextView textViewInfo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textViewInfo = (TextView)findViewById(R.id.info);

        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        if(nfcAdapter == null){
            Toast.makeText(this,
                    "NFC NOT supported on this devices!",
                    Toast.LENGTH_LONG).show();
            finish();
        }else if(!nfcAdapter.isEnabled()){
            Toast.makeText(this,
                    "NFC NOT Enabled!",
                    Toast.LENGTH_LONG).show();
            finish();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        Intent intent = getIntent();
        String action = intent.getAction();

        if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
            Toast.makeText(this,
                    "onResume() - ACTION_TAG_DISCOVERED",
                    Toast.LENGTH_SHORT).show();

            Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
            if(tag == null){
                textViewInfo.setText("tag == null");
            }else{
                String tagInfo = tag.toString() + "\n";

                tagInfo += "\nTag Id: \n";
                byte[] tagId = tag.getId();
                tagInfo += "length = " + tagId.length +"\n";
                for(int i=0; i<tagId.length; i++){
                    tagInfo += Integer.toHexString(tagId[i] & 0xFF) + " ";
                }
                tagInfo += "\n";

                String[] techList = tag.getTechList();
                tagInfo += "\nTech List\n";
                tagInfo += "length = " + techList.length +"\n";
                for(int i=0; i<techList.length; i++){
                    tagInfo += techList[i] + "\n ";
                }

                textViewInfo.setText(tagInfo);
            }
        }else{
            Toast.makeText(this,
                    "onResume() : " + action,
                    Toast.LENGTH_SHORT).show();
        }

    }
}


layout/activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/info"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>




Tag info of RFID card

Tag info of RFID key
reference: http://developer.android.com/guide/topics/connectivity/nfc/nfc.html

Next:
Android NFC read MifareClassic RFID tag, with android.nfc.action.TECH_DISCOVERED
Android NFC: readBlock() for MifareClassic, to dump data in RFID tag

8 comments:

Armin said...

I failed to read the tag as NfcAdapter.ACTION_TECH_DISCOVERED.equals(action) always return false

mbdroid said...

How to read nfc in ndk environment (native c++)? Thank You.

Anonymous said...

Thanks, it works :)

lodosunprensi said...

it works but can not read 0 (zero)

Sajed Mendoza said...

it goes to choose an action and when i selected new tag collected it says empty tag. i use SAMSUNG GALAXY S4

Bharath Kumar said...

if we need to scan 10,000 RFID's at a time and display as list then it should read or it leads to application not responding. Please tell me, thankU...

ilango gurusamy said...

What are the product details for RFID key and card? Where would i get that?

Andr.oid Eric said...

hello ilango gurusamy.

The key and card come with MFRC-522 RFID reader (http://arduino-er.blogspot.com/2015/10/arduino-uno-rfid-rc522-mfrc522-library.html). I bought from China online store taobao.com. It's a old model.