I followed this link and this is my code
Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(\"content://com.android.contacts/data/\" + \"MYNUMBER@s.whatsapp
I found the right way to do this and is just simple after you read this article: http://howdygeeks.com/send-whatsapp-message-unsaved-number-android/
phone and message are both String.
Source code:
try {
PackageManager packageManager = context.getPackageManager();
Intent i = new Intent(Intent.ACTION_VIEW);
String url = "https://api.whatsapp.com/send?phone="+ phone +"&text=" + URLEncoder.encode(message, "UTF-8");
i.setPackage("com.whatsapp");
i.setData(Uri.parse(url));
if (i.resolveActivity(packageManager) != null) {
context.startActivity(i);
}
} catch (Exception e){
e.printStackTrace();
}
Enjoy!