Receive verification token as sms in Xamarin.Android

Question

I need to create the registration for my application. I have created the sms sending server, so I can:

1. Click on the button "Send SMS"
2. After that, I receive the SMS with the token.
3. I can enter this token into EditText element.
4. Click the button "Verify".
5. And the token will be verified.

But now I need this token automatically placed from SMS into application's text box.

1. Click on the button "Send SMS"
2. After that, I receive the SMS with the token.
3. The token automatically places into EditText.
4. And the token is verified automatically too.

I try to use BroadcastReceiver, and it works for SMS. I can show the text like following:

using Android.App;
using Android.Content;
using Android.Telephony;
using Android.Widget;

namespace ReceiveMsg
{
    [BroadcastReceiver]
    [IntentFilter(
    new[] { "android.provider.Telephony.SMS_RECEIVED" }, Priority =(int)IntentFilterPriority.HighPriority)]
public class SmsReceiver : BroadcastReceiver
{

    public static readonly string INTENT_ACTION = "android.provider.Telephony.SMS_RECEIVED";
    protected string message, address = "";

    public override void OnReceive(Context context, Intent intent)
    {
        if(intent.HasExtra("pdus"))
        {
            var smsArray = (Java.Lang.Object[])intent.Extras.Get("pdus");
            foreach(var item in smsArray)
            {
                var sms = SmsMessage.CreateFromPdu((byte[])item);
                address = sms.OriginatingAddress;
                message = sms.MessageBody;
                Toast.MakeText(context, "Number: " + address + "Message: " + message, ToastLength.Short).Show();

            }
        }
    }
}

}

But how can I put the token from SMS into the token place automatically?

I need at first place to show the user Permission manager window for the confirmation, right?

So I added this in my AndroidManifest:

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

The user allows use this SMS.
The token parsed from SMS and will be stored inside the variable and will be shown inside the Textbox.

There is a token variable in the viewmodel.cs.
So I add public interface SmsListener here:

    private string _token;
    private bool _isSuccessed, _isInvalid;
    private readonly IMvxNavigationService _navigationService;

    public bool IsSucceeded
    {
        get
        {
            return _isSuccessed;
        }
        set
        {
            _isSuccessed = value;
            RaisePropertyChanged(() => IsSucceeded);
        }
    }
    public bool IsInvalid
    {
        get
        {
            return _isInvalid;
        }
        set
        {
            _isInvalid = value;
            RaisePropertyChanged(() => IsInvalid);
        }
    }

    public string Token
    {
        get
        {
            return _token;
        }
        set
        {
            _token = value;
            RaisePropertyChanged(() => Token);
        }
    }

    public VerificationViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;

        VerifyCommand = new MvxAsyncCommand(async () => {
            IsSucceeded = await RegistrationService.VerifyToken(Token);
            IsInvalid = !IsSucceeded;
        });

    }

    public IMvxAsyncCommand VerifyCommand { get; private set; }

    public interface SmsListener
        {
        void MessageReceived(string messageText);
        }

But I still don't understand how to use listener inside SmsReceiver

How can I summarize it? In order, the user will be able to allow to use this SMS and trust the automated process?

Answer 1

I need at first place to show the user Permission manager window for the confirmation, right?

Yes, if your target version >6.0, you need Request App Permissions.

how can I put the token from SMS into the token place automatically?

You can use Interface to achieve it. Please refer to this article.

---

1) You need define an interface, like the SmsListener:

public interface SmsListener {
        public void messageReceived(string messageText);
}

2) In your SmsReceiver, you need call it when you get the MessageBody;

3) Implement the interface in your Activity which contain the EditText, and in the interface's messageReceived method to update the EditText's text.

Note:

Don't forget use bindListener method or other method to instantiate your interface.

Update

SmsReceiver:

namespace ReceiveMsg
{
    [BroadcastReceiver]
    [IntentFilter(new[] { "android.provider.Telephony.SMS_RECEIVED" }, Priority =(int) IntentFilterPriority.HighPriority)] 
    public class SmsReceiver : BroadcastReceiver
    {

        public static readonly string INTENT_ACTION = "android.provider.Telephony.SMS_RECEIVED";
        protected string message, address = "";
        private OnReceiveSMSListener mOnReceiveSMSListener;//add interface
        public override void OnReceive(Context context, Intent intent)
        {
            if (intent.HasExtra("pdus"))
            {
                var smsArray = (Java.Lang.Object[])intent.Extras.Get("pdus");
                foreach (var item in smsArray)
                {
                    var sms = SmsMessage.CreateFromPdu((byte[])item);
                    address = sms.OriginatingAddress;
                    message = sms.MessageBody;
                    Toast.MakeText(context, "Number: " + address + "Message: " + message, ToastLength.Short).Show();
                    // call the interface if you get the message
                    mOnReceiveSMSListener.onReceived(message);
                }
            }
        }

        // interface
        public interface OnReceiveSMSListener
        {
            void onReceived(String message);
        }
        //used in activity
        public void setOnReceiveSMSListener(OnReceiveSMSListener onReceiveSMSListener)
        {
            mOnReceiveSMSListener = onReceiveSMSListener;
        }
    }
}

Activity:

   public class MainActivity : Activity,SmsReceiver.OnReceiveSMSListener
    {
        private SmsReceiver mSMSBroadcastReceiver = new SmsReceiver();
        private EditText mEt_code;
        public void onReceived(string message)
        {
            mEt_code.Text=message + "";
        }

        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);
            mEt_code = (EditText)FindViewById(Resource.Id.et_code);
            mSMSBroadcastReceiver.setOnReceiveSMSListener(this);
        }
    }

Manifest:

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