tablet-app/lib/Screens/PDF/pdf_view.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
//import 'dart:html';
import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_pdfview/flutter_pdfview.dart';
import 'package:manager_api/api.dart';
import 'package:path_provider/path_provider.dart';
import 'package:provider/provider.dart';
import 'package:tablet_app/Components/loading_common.dart';
import 'package:tablet_app/Models/tabletContext.dart';
import 'package:tablet_app/app_context.dart';
import 'package:tablet_app/constants.dart';


class PDFViewWidget extends StatefulWidget {
  final SectionDTO? section;
  PDFViewWidget({this.section});

  @override
  _PDFViewWidget createState() => _PDFViewWidget();
}

class _PDFViewWidget extends State<PDFViewWidget> {
  PdfDTO pdfDTO = PdfDTO();
  String remotePDFpath = "";
  final Completer<PDFViewController> _controller = Completer<PDFViewController>();
  int? pages = 0;
  int? currentPage = 0;
  bool isReady = false;
  String errorMessage = '';
  ValueNotifier<Map<String, int>> currentState = ValueNotifier<Map<String, int>>({'page': 0, 'total': 1});

  @override
  void initState() {
    print(widget.section!.data);
    pdfDTO = PdfDTO.fromJson(jsonDecode(widget.section!.data!))!;
    print(pdfDTO);
    super.initState();

    /*createFileOfPdfUrl(pdfDTO.source_!).then((f) {
      setState(() {
        remotePDFpath = f.path;
        print("paaath");
        print(remotePDFpath);
      });
    });*/
  }

  Future<File> createFileOfPdfUrl(TabletAppContext tabletAppContext, PdfDTO pdfDTO) async {
    Completer<File> completer = Completer();

    var file = await _checkIfLocalResourceExists(tabletAppContext, pdfDTO.resourceId!);

    if(file == null) {
      print("Start download file from internet!");
      try {
        // "https://berlin2017.droidcon.cod.newthinking.net/sites/global.droidcon.cod.newthinking.net/files/media/documents/Flutter%20-%2060FPS%20UI%20of%20the%20future%20%20-%20DroidconDE%2017.pdf";
        // final url = "https://pdfkit.org/docs/guide.pdf";
        final url = pdfDTO.resourceUrl!;
        final filename = url.substring(url.lastIndexOf("/") + 1);
        var request = await HttpClient().getUrl(Uri.parse(url));
        var response = await request.close();
        var bytes = await consolidateHttpClientResponseBytes(response);
        var dir = await getApplicationDocumentsDirectory();
        print("Download files");
        print("${dir.path}/$filename");
        File file = File("${dir.path}/$filename");

        await file.writeAsBytes(bytes, flush: true);
        completer.complete(file);
      } catch (e) {
        throw Exception('Error parsing asset file!');
      }
    } else {
      print("FOUND FILE PDF");
      completer.complete(file);
    }

    return completer.future;
  }

  @override
  void dispose() {
    //_webView = null;
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final appContext = Provider.of<AppContext>(context);
    TabletAppContext tabletAppContext = appContext.getContext();

    return pdfDTO.resourceUrl != null && pdfDTO.resourceUrl!.length > 0 ?
      Padding(
        padding: const EdgeInsets.all(12.5),
        child: FutureBuilder(
          future: createFileOfPdfUrl(tabletAppContext, pdfDTO),
          builder: (context, AsyncSnapshot<dynamic> snapshot) {
            print("snapshot.data");
            print(snapshot.data);
            if (snapshot.connectionState == ConnectionState.done) {
              return Stack(
                children: [
                  PDFView(
                    filePath: snapshot.data.path,
                    enableSwipe: true,
                    swipeHorizontal: true,
                    autoSpacing: true,
                    pageFling: true,
                    fitPolicy: FitPolicy.HEIGHT,
                    onRender: (_pages) {
                      //setState(() {
                        pages = _pages;
                        isReady = true;
                      //});
                    },
                    onError: (error) {
                      print(error.toString());
                    },
                    onPageError: (page, error) {
                      print('$page: ${error.toString()}');
                    },
                    onViewCreated: (PDFViewController pdfViewController) {
                      //_controller.complete(pdfViewController);
                    },
                    onPageChanged: (int? page, int? total) {
                      currentPage = page;
                      pages = total;
                      currentState.value = {'page': page!, 'total': total!};

                      print('page change: $page/$total');
                    },
                  ),
                  Positioned(
                      bottom: 20,
                      right: 20,
                      child: ValueListenableBuilder<Map<String, int>>(
                        valueListenable: currentState,
                        builder: (context, value, _) {
                          return Container(
                            //color: Colors.blueAccent,
                            child: Text("${value["page"]!+1}/${value["total"]!}",
                                style: TextStyle(color: Colors.black, fontSize: 30))
                          );
                        },
                      ),
                  ),
                ],
              );
            } else {
              return Center(
                  child: Container(
                      child: LoadingCommon()
                  )
              );
            }
          }
        ),
      ) :
      Center(child: Text("Le PDF ne peut pas être affiché, il n'existe pas", style: TextStyle(fontSize: kNoneInfoOrIncorrect)));
  }
} //_webView

Future<File?> _checkIfLocalResourceExists(TabletAppContext tabletAppContext, String resourceId) async {
  try {
    Directory? appDocumentsDirectory = Platform.isIOS ? await getApplicationDocumentsDirectory() : await getDownloadsDirectory();
    String localPath = appDocumentsDirectory!.path;
    Directory configurationDirectory = Directory('$localPath/${tabletAppContext.configuration!.id}');
    List<FileSystemEntity> fileList = configurationDirectory.listSync();

    if(fileList.any((fileL) => fileL.uri.pathSegments.last.contains(resourceId))) {
      File file = File(fileList.firstWhere((fileL) => fileL.uri.pathSegments.last.contains(resourceId)).path);
      return file;
    }
  } catch (e) {
    print("ERROR _checkIfLocalResourceExists PDF");
    print(e);
  }

  return null;
}