Get unique device ID (IMEI, MEID or ESN) of Android phones.

The method getDeviceId() of TelephonyManager returns the unique device ID, for example, the IMEI for GSM and the MEID or ESN for CDMA phones. Return null if device ID is not available.Permission READ_PHONE_STATE is required.

package com.AndroidTelephonyManager;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.widget.TextView;

public class AndroidTelephonyManager extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    TextView textDeviceID = (TextView)findViewById(R.id.deviceid);

    //retrieve a reference to an instance of TelephonyManager
    TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);

    textDeviceID.setText(getDeviceID(telephonyManager));

}

String getDeviceID(TelephonyManager phonyManager){

 String id = phonyManager.getDeviceId();
 if (id == null){
  id = "not available";
 }

 int phoneType = phonyManager.getPhoneType();
 switch(phoneType){
 case TelephonyManager.PHONE_TYPE_NONE:
  return "NONE: " + id;

 case TelephonyManager.PHONE_TYPE_GSM:
  return "GSM: IMEI=" + id;

 case TelephonyManager.PHONE_TYPE_CDMA:
  return "CDMA: MEID/ESN=" + id;

 /*
  *  for API Level 11 or above
  *  case TelephonyManager.PHONE_TYPE_SIP:
  *   return "SIP";
  */

 default:
  return "UNKNOWN: ID=" + id;
 }

}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<TextView
android:id="@+id/deviceid"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

The returned unique device ID is not the randomly generted 64-bit number, ANDROID_ID. For ANDROID_ID refer to the post: Get ANDROID_ID