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Read /Write NFC Tag With Android.

                                                               NFC  App Tutorial 
NFC :-  NFC is  the Near field communication, NFC short range wireless technology. NFC allows you to share small payload of Data between an NFC tag and an Android device.
The spectrum range from simple sticker and key ring to complex cards with integrated cryptographic hardware. Tag also differ in their chip technology.

NFC Access in the Android Manifest.
To get access to the NFC hardware, you have to apply for permission in the manifest. The  element so that your application shows up in google paly only for devices that have NFC Hardware.
<uses-permission android:name="android.permission.NFC" />
<uses-feature android:name="android.hardware.nfc" android:required="true" />


Filtering for NFC Intents :- Used only three filter for tag.

1.ACTION_NDEF_DISCOVERED
2.ACTION_TAG_DISCOVERED
3ACTION_TECH_DISCOVERED

ACTION_NDEF_DISCOVERED
<intent-filter>
    <action android:name="android.nfc.action.NDEF_DISCOVERED" />
    <category android:name="android.intent.category.DEFAULT" />
    <data android:mimeType="text/plain" />
</intent-filter>

ACTITON_TECH_DISCOVERED
Create nfc_tech_filter .xml inside res folder…
xml version="1.0" encoding="utf-8"?>
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
    <tech-list>
        <tech>android.nfc.tech.Ndef</tech>
       
    </tech-list>
</resources>

ACTION_TAG_DISCOVERED
<intent-filter>
    <action android:name="android.nfc.action.TAG_DISCOVERED" />
 </intent-filter>

EXPLAIN HOW TO USED ALL THOSE REQUIRED PERMISSIONS AND FUCTION.
1. First you have to Enable you NFC  Option in android device.
2. Create new android project in android studio.
3. Add some required permission in manifest.
Manifest.xml
xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.project.example.nfcreader">

    <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:roundIcon="@mipmap/ic_launcher_round"
        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.NDEF_DISCOVERED" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="text/plain" />
            </intent-filter>
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech_filter" />

        </activity>
        <activity android:name=".SecondActivity"></activity>
    </application>

</manifest>

4 Create nfc _tech_filter.xml inside res/xml directory.
xml version="1.0" encoding="utf-8"?>
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
    <tech-list>
        <tech>android.nfc.tech.Ndef</tech>
       
    </tech-list>
</resources>

5 Create activity_main.xml layout inside layout folder.
xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20sp"
        android:visibility="gone">

        <EditText
            android:id="@+id/edit_message"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:hint="message" />

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Write" />

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

</LinearLayout>

6 Add Main_activity.java.
package com.project.example.nfcreader;

import android.app.Activity;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
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.os.Parcelable;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

public class MainActivity extends Activity {

    public static final String ERROR_DETECTED = "No NFC tag detected!";
    public static final String WRITE_SUCCESS = "Text written to the NFC tag successfully!";
    public static final String WRITE_ERROR = "Error during writing, is the NFC tag close enough to your device?";
    NfcAdapter nfcAdapter;
    PendingIntent pendingIntent;
    IntentFilter writeTagFilters[];
    boolean writeMode;
    Tag myTag;
    Context context;

    TextView tvNFCContent;
    TextView message;
    Button btnWrite;
   
    public static String Id_Value;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context = this;

        tvNFCContent = (TextView) findViewById(R.id.nfc_contents);
        message = (TextView) findViewById(R.id.edit_message);
        btnWrite = (Button) findViewById(R.id.button);

      
      
        btnWrite.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v) {
                try {
                    if(myTag ==null) {
                        Toast.makeText(context, ERROR_DETECTED, Toast.LENGTH_LONG).show();
                    } else {
                        write(message.getText().toString(), myTag);
                        Toast.makeText(context, WRITE_SUCCESS, Toast.LENGTH_LONG ).show();
                    }
                } catch (IOException e) {
                    Toast.makeText(context, WRITE_ERROR, Toast.LENGTH_LONG ).show();
                    e.printStackTrace();
                } catch (FormatException e) {
                    Toast.makeText(context, WRITE_ERROR, Toast.LENGTH_LONG ).show();
                    e.printStackTrace();
                }
            }
        });

        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        if (nfcAdapter == null) {
            // Stop here, we definitely need NFC
            Toast.makeText(this, "This device doesn't support NFC.", Toast.LENGTH_LONG).show();
            finish();
        }
        readFromIntent(getIntent());

        pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
        IntentFilter tagDetected = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
        tagDetected.addCategory(Intent.CATEGORY_DEFAULT);
        writeTagFilters = new IntentFilter[] { tagDetected };
    }


    /**************Read From NFC Tag**********************************/
    private void readFromIntent(Intent intent) {
        String action = intent.getAction();
        if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action) || NfcAdapter.ACTION_TECH_DISCOVERED.equals(action) || NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {
            Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
            NdefMessage[] msgs = null;
            if (rawMsgs != null) {
                msgs = new NdefMessage[rawMsgs.length];
                for (int i = 0; i < rawMsgs.length; i++) {
                    msgs[i] = (NdefMessage) rawMsgs[i];
                }
            }
            buildTagViews(msgs);
        }
    }
    private void buildTagViews(NdefMessage[] msgs) {
        if (msgs == null || msgs.length == 0) return;

        String text = "";
//        String tagId = new String(msgs[0].getRecords()[0].getType());
        byte[] payload = msgs[0].getRecords()[0].getPayload();
        String textEncoding = ((payload[0] & 128) == 0) ? "UTF-8" : "UTF-16"; // Get the Text Encoding
        int languageCodeLength = payload[0] & 0063; // Get the Language Code, e.g. "en"
        // String languageCode = new String(payload, 1, languageCodeLength, "US-ASCII");

        try {
            // Get the Text
            text = new String(payload, languageCodeLength + 1, payload.length - languageCodeLength - 1, textEncoding);
        } catch (UnsupportedEncodingException e) {
            Log.e("UnsupportedEncoding", e.toString());
        }

        tvNFCContent.setText("NFC Content: " + text);
    
    }


    /****Write to NFC Tag**************************************************/
    private void write(String text, Tag tag) throws IOException, FormatException {
        NdefRecord[] records = { createRecord(text) };
        NdefMessage message = new NdefMessage(records);
        // Get an instance of Ndef for the tag.
        Ndef ndef = Ndef.get(tag);
        // Enable I/O
        ndef.connect();
        // Write the message
        ndef.writeNdefMessage(message);
        // Close the connection
        ndef.close();
    }
    private NdefRecord createRecord(String text) throws UnsupportedEncodingException {
        String lang       = "en";
        byte[] textBytes  = text.getBytes();
        byte[] langBytes  = lang.getBytes("US-ASCII");
        int    langLength = langBytes.length;
        int    textLength = textBytes.length;
        byte[] payload    = new byte[1 + langLength + textLength];

        // set status byte (see NDEF spec for actual bits)
        payload[0] = (byte) langLength;

        // copy langbytes and textbytes into payload
        System.arraycopy(langBytes, 0, payload, 1,              langLength);
        System.arraycopy(textBytes, 0, payload, 1 + langLength, textLength);

        NdefRecord recordNFC = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,  NdefRecord.RTD_TEXT,  new byte[0], payload);

        return recordNFC;
    }



    @Override
    protected void onNewIntent(Intent intent) {
        setIntent(intent);
        readFromIntent(intent);
        if(NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())){
            myTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        }
    }

    @Override
    public void onPause(){
        super.onPause();
        WriteModeOff();
    }

    @Override
    public void onResume(){
        super.onResume();
        WriteModeOn();
    }



    /********Enable Write**********************/
    private void WriteModeOn(){
        writeMode = true;
        nfcAdapter.enableForegroundDispatch(this, pendingIntent, writeTagFilters, null);
    }
    /* *****Disable Write**********************************************/
    private void WriteModeOff(){
        writeMode = false;
        nfcAdapter.disableForegroundDispatch(this);
    }
}

try this code…



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