How can I open WhatsApp's conversation activity using contact data?

Question

I want open what\'s app conversation activity cmp=com.whatsapp/.Conversation from my app.

How can I do this? I have contact phone number, contact id, c

Answer 1

 String KEY_QUICK_REPLY_TEXT = "Dear Valued Customer Thank you for contacting us your reference Number is "+refernceNumber ;
   Intent intent = new Intent(Intent.ACTION_SEND);
intent.setData(Uri.parse("http://api.whatsapp.com/send?phone="+phone +"&text="+KEY_QUICK_REPLY_TEXT));
                            startActivity(intent);

Toast.makeText(MainActivity.this, response, Toast.LENGTH_SHORT).show();