project_telephony/lib/ui/home/call.dart

import 'dart:async';
import 'dart:ui';

import 'package:call_log/call_log.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter_background_service/flutter_background_service.dart';
import 'package:telephony/telephony.dart';



Future<void> initializeService() async {
  // SharedPreferences preferences = await SharedPreferences.getInstance();
     final service = FlutterBackgroundService();

     await service.configure(
       androidConfiguration: AndroidConfiguration(
         // this will be executed when app is in foreground or background in separated isolate
         onStart: onStart,
         // auto start service
         autoStart: false,
         isForegroundMode: true,
       ),
       iosConfiguration: IosConfiguration(
         // auto start service
         autoStart: true,
         // this will be executed when app is in foreground in separated isolate
         onForeground: onStart,
         // you have to enable background fetch capability on xcode project
         onBackground: onIosBackground,
       ),
     );
  service.startService();
   }
// }

bool onIosBackground(ServiceInstance service) {
  WidgetsFlutterBinding.ensureInitialized();
  print('FLUTTER BACKGROUND FETCH');
  return true;
}


void onStart(ServiceInstance service ) async {
  DartPluginRegistrant.ensureInitialized();
  int flag = 0;
  String phoneNum="";
  String   callState;
 Timer.periodic(const Duration(seconds: 1), (timer)  async {
    CallState state = await Telephony.instance.callState;
    callState = state.name;
    // print(callState!+" $flag");
    if (callState == "IDLE") {
      if (flag != 0) {
        flag = 0;
        // print("object");
        final Iterable<CallLogEntry> result = await CallLog.query();
        phoneNum = result.first.number!;
        if(phoneNum.isEmpty){
          print("At Least 1 Person or Message Required");
        }else{
          print("你好$phoneNum");
          // final inbox = telephony.getInboxSms();
          Telephony.backgroundInstance.sendSms(to: phoneNum, message: "啦啦啦啦啦");
          // telephony.sendSms(to: phoneNum, message: "感谢来电");
           // _sendSMS('',[phoneNum]);
          // print("你好123123$phoneNum");
        }
      }
    } else if (callState == "RINGING") {
      flag++;
      print('flag $flag');
    } else if (callState == "OFFHOOK") {
      flag++;
      print('flag $flag');
    }
 });
}