Send Whatsapp message to specific group or Number from Android Application

I want to send a whatsapp message to specific number or group of whatsapp from my app with pre-type text Code for Specific Number

button1.addEventListener('click',function(e) {

Ti.Platform.openURL('whatsapp://?send?text=Hello?number=234243243');

});

Code For Group

button1.addEventListener('click',function(e) {

Ti.Platform.openURL('whatsapp://?send?text=Hello?groupname=abcxyz');

});

need help