problem with launching whatsapp to send a message with flutter url_launcher - flutter

Question

this is the function to send an WhatsApp message (or just launch the WhatsApp with the message)
in the Cipher.dart
void sendCodeByWhatsApp(
String phone,
String message,
) async {
String url() {
if (Platform.isAndroid) {
return "https://wa.me/$phone/?text=$message";
} else {
return "https://api.whatsapp.com/send?phone=$phone=$message";
}
}
if (await canLaunchUrl(Uri.parse(url()))) {
await launchUrl(Uri.parse(url()));
} else {
throw 'Could not launch ${url()}';
}
}
and here I use it:
ElevatedButton(
child: const Icon(Icons.whatsapp, color: Colors.white,),
onPressed: (){
Cipher().sendCodeByWhatsApp(encrypt.encrypt, phone.text);
},
),
when adding a number and message, just open a page with WhatsApp logo, tells me:
we couldn't find the page you were looking for

Answer 1

Refer to this to get how to use the link properly link
There may also be an error if the number includes the country code like
[phone]
Will give an error. The phone should not include the country code.

Answer 2

after doing some search, finally found the solution:
same code above, but the URL should be like this:
"whatsapp://send?phone=$phone&text=${Uri.parse(message)}";
for android, and it is working like a charm...

Answer 3

Change the ? to & and it will open the WhatsApp page in the browser for you
"https://wa.me/$phone/&text=$message";