Unit-App/lib/Util/Util.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:flutter/services.dart';
import 'package:http/http.dart';
import 'package:flutter/material.dart';
import 'package:flushbar/flushbar.dart';
import 'package:http/io_client.dart';
import '../main.dart';
import 'package:location/location.dart';
import 'package:permission_handler/permission_handler.dart' as pHandler;
// import 'package:app_settings/app_settings.dart';

class Util{
  bool useLocal = false;
  JsonDataPostRaw(Map jsonData, String url,{timeout:false}) async{
    const JsonDecoder decoder = const JsonDecoder();
    try {
      var response;
      if (timeout)
        response = await http.post(
            Uri.parse(url), headers: {'Content-type': 'application/json'},
            body: json.encode(jsonData)).timeout(
            const Duration(seconds: 10));
      else
        response = await http.post(
            Uri.parse(url), headers: {'Content-type': 'application/json'},
            body: json.encode(jsonData));
      final Map data = decoder.convert(response.body);
      return data;
    } on TimeoutException catch(e){
      return {"STATUS":0,"DATA":"Request Timeout"};
    }
    on HandshakeException catch(e){
      if(useLocal){
        return {"STATUS":0,"DATA":"Not Connected to Server. $e"};
      }
      else{
        useLocal = true;
        http = IOClient(HttpClient(context: clientContext));
        return await JsonDataPostRaw(jsonData, url,timeout:timeout);
      }

    }
    on Exception catch(exception){
      print(url);
//      Toast("Not Connected to Server", Colors.red);
      return {"STATUS":0,"DATA":"Not Connected to Server. $exception"};
    }
  }

  showLoading(context,{dissmissable=false,onwillpop}){
    showDialog(
        context: context,
        builder: (BuildContext context) {
      return WillPopScope(
        onWillPop: onwillpop??()async{return true;},
        child: new Center(
          child: new CircularProgressIndicator(),
        ),
      );
    },
    barrierDismissible: dissmissable,
    );
  }
  permissionCheck(context,pHandler.Permission permissionType,ifGranted,{customMessage=''})async{
    pHandler.PermissionStatus permission = await permissionType.status;
    if(permission!= pHandler.PermissionStatus.granted){
      if(permission== pHandler.PermissionStatus.denied || permission== pHandler.PermissionStatus.restricted){
        showFlushbar(context,'${permissionType.toString().substring(permissionType.toString().lastIndexOf('.')+1)} permission is needed$customMessage. Please grant the permission!');
        await Future.delayed(Duration(seconds: 3));
        permission = await permissionType.request();
      }
      if(permission== pHandler.PermissionStatus.permanentlyDenied) {
        showFlushbar(context,'It seems, your system security explicitly denied access to your ${permissionType.toString().substring(permissionType.toString().lastIndexOf('.')+1)} permission. Please MANUALLY enable it in setings!');
        await Future.delayed(Duration(seconds: 3));
        pHandler.openAppSettings();
        SystemChannels.platform.invokeMethod('SystemNavigator.pop');
      }
      if(permission== pHandler.PermissionStatus.denied || permission== pHandler.PermissionStatus.restricted){
        showFlushbar(context,'${permissionType.toString().substring(permissionType.toString().lastIndexOf('.')+1)} permission is needed$customMessage. Please grant the permission!');
        await Future.delayed(Duration(seconds: 3));
        permission = await permissionType.request();
      }
      await permissionCheck(context,permissionType,ifGranted);
    }
    else{
      await ifGranted();
    }
  }
  showFlushbar(context,text,{color:Colors.grey}){
    Flushbar(
        message:  "$text",
        backgroundColor: color,
        duration:  Duration(seconds: 5),
      )..show(context);
  }
  streamLocation(context)async{
    print('checking location');
    await permissionCheck(context,pHandler.Permission.locationWhenInUse,()async{
      location.changeSettings(accuracy: LocationAccuracy.high);
      bool gpsEnabled = false;
      if(await location.serviceEnabled()){
        gpsEnabled = await location.serviceEnabled();
      }
      else{
        print('requesting gps');
        gpsEnabled = await location.requestService();
        await streamLocation(context);
      }
//    print([gpsEnabled,permissionEnabled]);
      if(gpsEnabled){
          if(locationStream==null){
            locationStream = location.onLocationChanged.listen((LocationData event) {
              currentPosisiton = event;
            });
          }
      }
    },customMessage: " to locate your REAL location");
  }
}