Use preview3.

[kbagchiGWC]

https://www.twilio.com/docs/voice/voip-sdk/android/changelog#300-preview3

3.0.0-preview3

• Programmable Voice Android SDK 3.0.0-preview3 [bintray], [docs]

Enhancements

API Changes:

• Nullability annotations have been added. Methods that expect @NonNull parameters throw NullPointerException. Methods that validate parameters for a specified input throw IllegalStateException if invalid.
• Moved CallState to Call.State
• Provide a stateless mechanism for processing push messages related to call invites and call invite cancellations. This API no longer raises errors when processing invalid messages, instead a boolean value is returned when handleMessage(context, data) is called. The boolean value is true when the provided data results in a CallInvite or CancelledCallInvite. If handleMessage(context, data) returns false it means the data provided was not a Twilio Voice push message. The CallInvite has an accept() and reject() method. While the CancelledCallInvite simply provides the to, from, and callSid fields also available in the CallInvite. The method getCallSid() can be used to associate a CallInvite with a CancelledCallInvite.
  • Migrated the API CallInvite to CallInvite and CancelledCallInvite.

       // Processing push messages in 2.X
       handleMessage(context, data, new MessageListener() {
           @Override
           void onCallInvite(CallInvite callInvite) {
                 // Check state and process invite
                 if (callInvite.getState().equals(PENDING)) {
                     // Show notification to answer or reject call
                 } else if(callInvite.getState().equals(CANCELLED)) {
                     // Hide notification
                 }
           }

           @Override
           void onError(MessageException messageException) {
               // Invalid data was provided
           }
       });

       // Processing push messages in 3.X
       boolean handled = handleMessage(context, data, new MessageListener() {
           @Override
           void onCallInvite(CallInvite callInvite) {
               // Show notification to answer or reject call
           }

           @Override
           void onCancelledCallInvite(CancelledCallInvite callInvite) {
               // Hide notification
           }
       });

       if(!handled) {
           // This message is not a Twilio voice push message
       }

• Introduced call.getStats() method that returns a list of StatsReport with metrics for all the audio tracks in a call.

	call.getStats(new StatsListener() {
        @Override
        public void onStats(@NonNull List<StatsReport> statsReports) {
            // Process statsReports
        }
	});