How to start Viber call from an Android app [new version]?

Question

A while ago I created this post, and my colleague and I have found two different answers to it (both of them worked):

1. First solution was to use

   Int

Answer 1

According to Viber's manifest, there is activity "com.viber.voip.phone.PhoneActivity" that is responsible for action "com.viber.voip.action.CALL". In new version of Viber (4.2.1.1) this activity is marked by android:exported="false". As result, it's not possible anymore to start this activity from external applications...

Edit

This code opens welcome screen for specified contact

String sphone = "12345678";
Uri uri = Uri.parse("tel:" + Uri.encode(sphone)); 
Intent intent = new Intent("android.intent.action.VIEW");
intent.setClassName("com.viber.voip", "com.viber.voip.WelcomeActivity");
intent.setData(uri); 
context.startActivity(intent);

but user should click button "free call" to start call.