Xamarin Forms - SMS BroadcastReceiver in Android failing to work - xamarin.forms

Question

This seems to be a simple task, but I`m failing to do it. Saw a bunch of tutorials and stuff. Maybe someone can help me.
I'm starting from a Xamarin Forms App, that will have a task specific for Android (Targeting Android 8.0 - Oreo).
So to test I've made as follow (XF 3.2.0.839982). Told this mainly because it don't have a OnResume, OnPause, On....methods...(or I don't know about them).
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity, Application.IActivityLifecycleCallbacks
{
SMSBroadcastReceiver myreceiver;
IntentFilter intentFilter;
protected override async void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
var buttonbtnsendmessage = (Button)FindViewById(Resource.Id.sendBroadcast);
myreceiver = new SMSBroadcastReceiver();
intentFilter = new IntentFilter(SMSBroadcastReceiver.IntentAction);
intentFilter.Priority = 1000;
RegisterReceiver(myreceiver, intentFilter);
}
}
public class SMSBroadcastReceiver : BroadcastReceiver
{
public static string IntentAction = "android.provider.Telephony.SMS_RECEIVED";
public override void OnReceive(Context context, Intent i)
{
if (i.Action != IntentAction)
{
return;
}
Toast.MakeText(context, "Received broadcast in MyBroadcastReceiver, " +
" value received: " + i.GetStringExtra("key"),
ToastLength.Long).Show();
}
}
and Manifest
<uses-sdk android:minSdkVersion="19" android:targetSdkVersion="26" />
<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.RECEIVE_SMS" />
<uses-permission android:name="android.permission.READ_SMS" />
<uses-permission android:name="android.permission.BROADCAST_SMS" />
But it do not fall in my receiver when I get a SMS.
Just to check if it would work at all, I changed the IntentAction to "MY_TEST", and sent the broadcast from another app, and it was able to Toast.
Any Ideas?

Answer 1

Xamarin Forms - SMS BroadcastReceiver in Android failing to work
You are missing a lot is in your code.
Requesting Runtime Permissions in Android Marshmallow +
Beginning in Android 6.0 (API level 23), users grant permissions to apps while the app is running, not when they install the app. You should request permissions at runtime.
System permissions are divided into two categories, normal and dangerous:
Normal permissions do not directly risk the user's privacy. If your app lists a normal permission in its manifest, the system grants the permission automatically.
Dangerous permissions can give the app access to the user's confidential data. If you list a dangerous permission, the user has to explicitly give approval to your app during the runtime of the app.
READ_SMS is categorized as Dangerous permissions, so you should check this permissions manually for API level 23 and above.
Adorn BroadcastReceiver with the BroadcastReceiverAttribute
For more detail information, please refer to the official document: Broadcast Receivers in Xamarin.Android
Here is an example:
[BroadcastReceiver(Enabled = true)]
[IntentFilter(new[] { "android.provider.Telephony.SMS_RECEIVED" })]
class SMSBroadcastReceiver: BroadcastReceiver
{
public static string IntentAction = "android.provider.Telephony.SMS_RECEIVED";
public override void OnReceive(Context context, Intent i)
{
if (i.Action != IntentAction)
{
return;
}
Toast.MakeText(context, "Received broadcast in MyBroadcastReceiver, " +
" value received: " + i.GetStringExtra("key"),
ToastLength.Long).Show();
}
}