Asset-App/lib/util/utils.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:http/http.dart' as http;
import 'package:barcode_scan2/barcode_scan2.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:permission_handler/permission_handler.dart' as pHandler;


class Util{

  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){
        showToast('NORMAL', '${permissionType.toString().substring(permissionType.toString().lastIndexOf('.')+1)} permission is needed$customMessage. Please grant the permission!');
        await Future.delayed(Duration(seconds: 3));
        permission = await permissionType.request();
      }
      if(permission== pHandler.PermissionStatus.permanentlyDenied) {
        showToast('ERROR', 'It seems, your system security explicitly denied access to your ${permissionType.toString().substring(permissionType.toString().lastIndexOf('.')+1)} permission. Please MANUALLY enable it in setings!');
        await Future.delayed(Duration(seconds: 3));
        pHandler.openAppSettings();
        SystemChannels.platform.invokeMethod('SystemNavigator.pop');
      }
      if(permission== pHandler.PermissionStatus.denied || permission== pHandler.PermissionStatus.restricted){
        showToast('NORMAL', '${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();
    }
  }

  scan()async{
    String BarcodeText ='';
    try{
      ScanResult result = await BarcodeScanner.scan();
      BarcodeText = result.rawContent;
      return {'STATUS':1,'DATA':BarcodeText};
    }
    catch(e){
      return {'STATUS':0,'DATA':e};
    }
  }

  showLoadingFuture(context,future,{dismiss=false,onWillPop})async {
    var dialogContext;
    showDialog(
      context: context,
      builder: (BuildContext context) {
        dialogContext = context;
        return WillPopScope(
          onWillPop: onWillPop??()async{return true;},
          child: new Center(
            child: new CircularProgressIndicator(),
          ),
        );
      },
      barrierDismissible: dismiss,
    );
    var res = await future;
    Navigator.pop(dialogContext);
    return res;
  }

  JsonDataPostRaw(Map jsonData, String url,{timeout:false,duration:10}) async{
    const JsonDecoder decoder = const JsonDecoder();
    try {
      var headers = {'device':'mobile','Content-type': 'application/json'};
      var response;
      if (timeout)
        response = await http.post(
            Uri.parse(url), headers: headers,
            body: json.encode(jsonData)).timeout(
            Duration(seconds: duration));
      else
        response = await http.post(
            Uri.parse(url), headers: headers,
            body: json.encode(jsonData));
      final Map data = decoder.convert(response.body);
      return data;
    } on TimeoutException catch(e){
      return {"STATUS":"ERROR","ERROR":"Request Timeout"};
    }
    on Exception catch(exception){
      print(url);
//      Toast("Not Connected to Server", Colors.red);
      return {"STATUS":"ERROR","ERROR":"Not Connected to Server. $exception"};
    }
  }

  showToast(type,text)async{
    await Fluttertoast.cancel();
    Fluttertoast.showToast(
        msg: "$text",
        toastLength: Toast.LENGTH_SHORT,
        gravity: ToastGravity.BOTTOM,
        timeInSecForIosWeb: 1,
        backgroundColor: (type=='ERROR')?Colors.red:(type=='SUCCESS')?Colors.green:Colors.black38,
        textColor: Colors.white,
        fontSize: 16.0
    );
  }
  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,
    );
  }

  checkinternet()async{
    try {
      var result = await InternetAddress.lookup('google.com').timeout(Duration(seconds: 3),onTimeout: (){return null;});
      if (result!=null && result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
        return true;
      }
      else return false;
    } on SocketException catch (_) {
      return false;
    }
  }

}