Login Method with API

loginMethod.dart

  var usernameController = TextEditingController();
  var passwordController = TextEditingController();
  
  Future<void> loginMethod() async {
    if (usernameController.text.isNotEmpty && passwordController.text.isNotEmpty) {
      var response = await http.post(
        Uri.parse(
            // your API
            ""),
        body: ({
          'username': usernameController.text,
          'password': passwordController.text,
        }),
      );


      if (response.statusCode == 200) {
        // check the response
        print("Response Status: ${response.statusCode}");
      } else {
        // ignore: use_build_context_synchronously
        ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text("Your data is incorrect!")));
      }
      
    } else {
      ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text("Username and password must be written!")));
    }
  }