The dialer is not showing full ussd code eg: *123*1# - dart

Question

I am using the url_launcher plugin for call, but the dialer is not showing the # character:
String url = 'tel:*123#';
if (await canLaunch(url)) {
await launch(url);
} else {
throw 'Could not launch $url';
}

Answer 1

You need to use URL encoding for special character in a URL.
So # equals %23
This will work launch('tel:\*123\%23');
Other Way is to encode the number typed by user and pass it through Uri.encodeFull(urlString) or Uri.encodeComponent(urlString)
Like this.
launch("tel:" + Uri.encodeComponent('*123#'));

Answer 2

Disclaimer: plugin author here.
Do you want the phone call user interface to open or would you rather make the request silently? If you prefer to do it without popping the phone call UI, Android introduced in API level 26 the method sendUssdRequest.
I made a Flutter plugin called ussd_service to be able to easily access it from dart in a Flutter application. It can be used in the following manner:
import 'package:ussd_service/ussd_service.dart';
makeMyRequest() async {
int subscriptionId = 1; // sim card subscription Id
String code = "*21#"; // ussd code payload
try {
String ussdSuccessMessage = await UssdService.makeRequest(subscriptionId, code);
print("succes! message: $ussdSuccessMessage");
} on PlatformException catch (e) {
print("error! code: ${e.code} - message: ${e.message}");
}
};
makeMyRequest();
Hope this helps! Let me know on the Github repo's issues if you have any issue with it.