如何从Android应用程序开放Viber公共聊天?

Here ):

var viberPackageName = "com.viber.voip";
var phone = "5757575757";

try
{
    StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse("viber://add?number=$phone")));
}
catch
{
    try
    {
        StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse("market://details?id=$viberPackageName")));
    }
    catch
    {
        StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse("https://play.google.com/store/apps/details?id=$viberPackageName")));
    }
 }