How to check user entered own phone number in EditText?

Question

Mobile number will be entered in an edittext by user on registration page in my Android application. How can I check that user entered his/her mobile number not other\'s ?

Answer 1

Getting the phone number using getLine1Number() is not secure nor certain.

It is generally accepted because this whole "getting the phone number" is clash of multiple issues such as user's privacy, carrier's branding, and even the vendor's.

Anyway, unlike ios, android's android.provider.Telephony.SMS_RECEIVED makes the whole process very convenient and seemless to the user: You get to capture the sms and read it without any need of the user's intervention.

What is one way of doing it?

On your server, upon receiving the request to verify a phone number, you should generate a secret code, tokenSent, and send it to the app. Now, your server should send this code by sms to the specified phone number. The app by now should have a registered receiver listening for the android.provider.Telephony.SMS_RECEIVED intent. Once received, the app verifies that the tokenSent is identical to what it received from the server. At this point, phone registration is done and the server can be notified.

What could go wrong?

Generally, such apps are usually paid apps and it is not the user's good to attempt anything. Still, the user might enter a wrong number which he right now has. Then upon receiving the sms, he could forward it to the mobile where the app is registering. The app will then receive the tokenSent and wrongly verify the phone number.

How can we tackle this?

The feasibility of the solution depends on whether the sms provider allows your server to know the sender's phone number. This is probably (AFAIK) not gonna happen but if it does then you're in luck. That way, the app can, upon receiving the tokenSent, send it back to the server along with the sender of the sms. The server then can verify that this is the sms that was originated from your service provider.

Any more feasible solution? (If I am really paranoid)

In this case, the best solution, I believe, would be to request a tokenSent from your server. The server saves a generated tokenSent along with the phone number entered and sends this token to the app. The app notifies the user that registration will cost him 1 sms. Once the user accepts, you can easily send an sms in the background containing this tokenSent to a certain service. The server, once receives this tokenSent verifies the user using the token and the sender of the sms. Of course, this may seem a bit harassing and infringing to the user but it is the most secure way especially for such a paranoid (reading this part).

Formalities :P

Add Permissions in Manifest

<uses-permission android:name="android.permission.RECEIVE_SMS">

Register the receiver (Do this just before you send the sms to the phone)

registerReceiver(new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getExtras() != null)
        {
            Object[] pdus = (Object[]) intent.getExtras().get("pdus");
            SmsMessage[] msgs = new SmsMessage[pdus.length];            
            for (int i=0; i<msgs.length; i++){
                msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);                
               String from = msgs[i].getOriginatingAddress();                     
                String body = msgs[i].getMessageBody().toString();
                //here is the body
                //...
                unregisterReceiver(this); //If you are done with verification
            }
        }  
    }
}, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));

Answer 2

I solved it my self. Here is my working code. MainActivity Class :

   public class MainActivity extends Activity
{    
    Button submit;
    EditText contact;
    static String phNo;
    ProgressDialog progress;
    static Boolean wasMyOwnNumber;
    static Boolean workDone;
    final static int SMS_ROUNDTRIP_TIMOUT = 30000;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        contact = (EditText)findViewById(R.id.mobileNumber);
        submit = (Button) findViewById(R.id.button1);
        wasMyOwnNumber = false;
        workDone = false;
        submit.setOnClickListener(new OnClickListener()
        {
                public void onClick(View v)
                {
                    phNo = contact.getText().toString();
                    new CheckOwnMobileNumber().execute();
                }
        });
    }

    private class CheckOwnMobileNumber extends AsyncTask<String, Void, String>
    {
        @Override
        protected void onPostExecute(String result)
        {
            // TODO Auto-generated method stub
            if(progress.isShowing())
            {
                progress.dismiss();
                if(wasMyOwnNumber)
                {
                    Toast.makeText(getApplicationContext(), "Number matched.", Toast.LENGTH_LONG).show();
                    wasMyOwnNumber = false;
                    workDone = false;
                }
                else
                {
                    Toast.makeText(getApplicationContext(), "Wrong number.", Toast.LENGTH_LONG).show();
                    wasMyOwnNumber = false;
                    workDone = false;
                    return;
                }
            }
            super.onPostExecute(result);
        }

        @Override
        protected String doInBackground(String... params)
        {
            // TODO Auto-generated method stub
            String msg = phNo;
            try
            {
                SmsManager sms = SmsManager.getDefault();
                sms.sendTextMessage(phNo, null, msg, null, null);
                timeout();
            }
            catch(Exception ex)
            {
                Log.v("Exception :", ""+ex);
            }
            return null;
        }

        @Override
        protected void onPreExecute() 
        {
            // TODO Auto-generated method stub
            progress = ProgressDialog.show(MainActivity.this, "","Checking Mobile Number...");
            progress.setIndeterminate(true);
            progress.getWindow().setLayout(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
            super.onPreExecute();
        }
    }

    private boolean timeout()
    {
           int waited = 0;
           while (waited < SMS_ROUNDTRIP_TIMOUT)
           {
              try
              {
                Thread.sleep(100);
              }
              catch (InterruptedException e)
              {
                // TODO Auto-generated catch block
                e.printStackTrace();
              }
              waited += 100;
              if(phoneNumberConfirmationReceived())
              {
                  waited=SMS_ROUNDTRIP_TIMOUT;
                  workDone = true;
              }
           }
           /*Log.v("MainActivity:timeout2: Waited: " , ""+waited);
           Log.v("MainActivity:timeout2:Comparision: ", ""+ phoneNumberConfirmationReceived());
           Log.v("MainActivity:timeout2: WorkDone value after wait complete : ", ""+workDone);*/
        return workDone;
    }

    private boolean phoneNumberConfirmationReceived()
    {
        if(wasMyOwnNumber)
        {
            workDone = true;
        }
        return workDone;
    }
}

SMSReceiver Code :

 public class SMSReceiver extends BroadcastReceiver
{
    private static final String ACTION_SMS_RECEIVED = "android.provider.Telephony.SMS_RECEIVED";
    Context mContext;
    private Intent mIntent;
    static String address, str = null;
    boolean isSame;

    // Retrieve SMS
    public void onReceive(Context context, Intent intent)
    {
        mContext = context;
        mIntent = intent;
        String action = intent.getAction();
        if(action.equals(ACTION_SMS_RECEIVED))
        {
            SmsMessage[] msgs = getMessagesFromIntent(mIntent);
            if (msgs != null)
            {
                for (int i = 0; i < msgs.length; i++)
                {
                    address = msgs[i].getOriginatingAddress();
                    str = msgs[i].getMessageBody().toString();
                }
            }
            Log.v("Originating Address : Sender :", ""+address);
            Log.v("Message from sender :", ""+str);
            isSame = PhoneNumberUtils.compare(str, MainActivity.phNo);
            Log.v("Comparison :", "Yes this true. "+isSame);
            if(isSame)
            {
                 MainActivity.wasMyOwnNumber = isSame;
                 MainActivity.workDone=true;
            }

            // ---send a broadcast intent to update the SMS received in the
            // activity---
            Intent broadcastIntent = new Intent();
            broadcastIntent.setAction("SMS_RECEIVED_ACTION");
            broadcastIntent.putExtra("sms", str);
            context.sendBroadcast(broadcastIntent);
        }
    }

    public static SmsMessage[] getMessagesFromIntent(Intent intent)
    {
        Object[] messages = (Object[]) intent.getSerializableExtra("pdus");
        byte[][] pduObjs = new byte[messages.length][];

        for (int i = 0; i < messages.length; i++)
        {
            pduObjs[i] = (byte[]) messages[i];
        }

        byte[][] pdus = new byte[pduObjs.length][];
        int pduCount = pdus.length;
        SmsMessage[] msgs = new SmsMessage[pduCount];
        for (int i = 0; i < pduCount; i++)
        {
            pdus[i] = pduObjs[i];
            msgs[i] = SmsMessage.createFromPdu(pdus[i]);
        }
        return msgs;
    }
}

No ANR found.

Answer 3

Just want to add a bit here to above explanations in the above answers. Which will save time for others as well.

In my case this method didn't returned any mobile number, an empty string was returned. It was due to the case that I had ported my number on the new sim. So if I go into the Settings>About Phone>Status>My Phone Number it shows me "Unknown".

This is probably because you have ported the number from one network to other.

If you are not able to check the number from API Then:

One way of doing that is you generate a text message to the Number and send a Random Generated no to the Mobile Number. You will have to ask the user to enter this Random generated number into your Application. Once it is entered in the application then you can send it onto the server to check whether the number passed in the text is correct or not (Which you have already saved on server against that mobile number).

I hope this makes sense.

Answer 4

Its not guaranteed that tMgr.getLine1Number(); will always return your SIM card's number. Because it depends on the availability of number in SIM card. Like in my case, my Tre-Sweden SIM card doesn't contain my phone number.

But if you put the SIM card into an old SonyEricsson or Nokia phone, then you would get an option to edit this number (on SIM). Once its done, the android device will recognize the number and will show you.

Besides, if you do get your phone number through the code, then the best way to compare two numbers is:

boolean isSame = PhoneNumberUtils.compare(num1, num2);

---

Alternatively, you may implement some sort of pin-code verification logic (like Viber, WhatsApp or other application does) in which you ask the user to enter their phone number during registration. Later, that phone number is sent to the server and a pin-code is generated against that number which is sent to the user via SMS. Finally, the user has to enter that pin-code (received in SMS) to complete the registration.

Or

Simply send an SMS from user's device (with a consent) to your server/device and get to know their phone number.

Answer 5

public class MainActivity extends Activity{    

    Button submit;
    EditText contact;
    String phNo;
    ProgressDialog progress;
    Boolean wasMyOwnNumber = false;
Boolean workDone = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        contact = (EditText)findViewById(R.id.mobileNumber);
        submit = (Button) findViewById(R.id.button1);

        submit.setOnClickListener(new OnClickListener()
        {
                public void onClick(View v)
                {
                    phNo = contact.getText().toString();
                    new CheckOwnMobileNumber().execute();
                    Toast.makeText(getApplicationContext(), phNo, Toast.LENGTH_LONG).show();
                }
        });



    }

    private class CheckOwnMobileNumber extends AsyncTask<String, Void, String>
    {
        @Override
        protected void onPostExecute(String result)
        {
            // TODO Auto-generated method stub
            if(progress.isShowing())
            {

                progress.dismiss();
                // Check SMS Received or not after that open dialog date
                /*if(SMSReceiver.str.equals(phNo))
                {
                    Toast.makeText(getApplicationContext(), "Thanks for providing your          number.", Toast.LENGTH_LONG).show();
wasMyOwnNumber=true;workDone=true;
                }
                else
                {
                    Toast.makeText(getApplicationContext(), "Provide your own mobile number please.", Toast.LENGTH_LONG).show();
wasMyOwnNumber=false;workDone=true;
                    return;
                }*/


            }
        }

        @Override
        protected String doInBackground(String... params)
        {
            // TODO Auto-generated method stub
            String msg = phNo;
            try
            {
                sendSMS(phNo, msg);
                int count=0;
                     while(!workDone)
                          {count++;}
            }
            catch(Exception ex)
            {
                Log.v("Exception :", ""+ex);
            }
            return null;
        }

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            progress = ProgressDialog.show(MainActivity.this, "","Checking Mobile Number...");
            progress.setIndeterminate(true);
            progress.getWindow().setLayout(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
            super.onPreExecute();
        }

}

    private void sendSMS(String phoneNumber, String message)
        {        
            //PendingIntent pi = PendingIntent.getActivity(getApplicationContext(), 0, new Intent(getApplicationContext(), MainActivity.class), 0);                
            SmsManager sms = SmsManager.getDefault();
            sms.sendTextMessage(phoneNumber, null, message, null, null);        
        }

public class SMSReceiver extends BroadcastReceiver
{
private static final String ACTION_SMS_RECEIVED = "android.provider.Telephony.SMS_RECEIVED";
Context mContext;
private Intent mIntent;
static String address, str = null;

// Retrieve SMS
public void onReceive(Context context, Intent intent) {
    mContext = context;
    mIntent = intent;

    String action = intent.getAction();

    if(action.equals(ACTION_SMS_RECEIVED))
    {
        SmsMessage[] msgs = getMessagesFromIntent(mIntent);
        if (msgs != null)
        {
            for (int i = 0; i < msgs.length; i++)
            {
                address = msgs[i].getOriginatingAddress();
                str = msgs[i].getMessageBody().toString();
            }
        }   

        // ---send a broadcast intent to update the SMS received in the
        // activity---
        workDone=true;
        Intent broadcastIntent = new Intent();
        broadcastIntent.setAction("SMS_RECEIVED_ACTION");
        broadcastIntent.putExtra("sms", str);
        context.sendBroadcast(broadcastIntent);

    }

}

public static SmsMessage[] getMessagesFromIntent(Intent intent)
{
    Object[] messages = (Object[]) intent.getSerializableExtra("pdus");
    byte[][] pduObjs = new byte[messages.length][];

    for (int i = 0; i < messages.length; i++)
    {
        pduObjs[i] = (byte[]) messages[i];
    }

    byte[][] pdus = new byte[pduObjs.length][];
    int pduCount = pdus.length;
    SmsMessage[] msgs = new SmsMessage[pduCount];
    for (int i = 0; i < pduCount; i++)
    {
        pdus[i] = pduObjs[i];
        msgs[i] = SmsMessage.createFromPdu(pdus[i]);
    }
    return msgs;
}
}
    }