来自 Firebase 存储的 PDF 未显示在 Flutter 视图中

Question

当用户点击按钮时，我有这段代码可以显示 pdf。但是，它不起作用。 我没有看到我在这里做错了什么。拜托，你能帮我解决这个问题吗？非常感谢。 我得到了一个新的视图，但视图是空白的。 当文件是本地文件时，它工作正常，我的意思是在我的手机上。但是当pdf在firebase上时，我得到一个空白页。 我已经修改了代码。

我再次修改了代码。但仍然无法正常工作。如果你们中的一个人可以帮助我解决这个问题，我们将不胜感激。我的项目现在被阻止了。这让我发疯了。非常感谢。

//on another page

Navigator.pop(context);
              Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => Display_PDF_Selected_Storage(task_Attachments[j].toString())));

import 'dart:io';
import 'dart:typed_data';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_pdfview/flutter_pdfview.dart';
import 'package:path_provider/path_provider.dart';

class Display_PDF_Selected_Storage extends StatefulWidget {
  final int pdfIndex;
  final String selectedPdfPath;

  Display_PDF_Selected_Storage(this.selectedPdfPath, {Key key, this.pdfIndex, }) : super(key: key);
  @override
  _Display_PDF_Selected_StorageState createState() => _Display_PDF_Selected_StorageState(selectedPdfPath,pdfIndex);
}


class _Display_PDF_Selected_StorageState extends State<Display_PDF_Selected_Storage> {
  PDFViewController controller;

  int indexPage = 0, indexPdf, pages = 0, currentPage = 0;
  bool isReady = false;
  String selectedPdfPath;

  _Display_PDF_Selected_StorageState(this.selectedPdfPath,this.indexPdf,);

  @override
  Widget build(BuildContext context) {
    final text = '${indexPage + 1} of $pages';

    return Scaffold(
      appBar: new AppBar(
        title: new Text(selectedPdfPath.split('/').last),
        actions: pages >= 2
        ? [
        Center(child: Text(text)),
        IconButton(
          icon: Icon(Icons.chevron_left, size: 32),
          onPressed: () {
            final page = indexPage == 0 ? pages : indexPage - 1;
            controller.setPage(page);
          },
        ),
        IconButton(
          icon: Icon(Icons.chevron_right, size: 32),
          onPressed: () {
            final page = indexPage == pages - 1 ? 0 : indexPage + 1;
            controller.setPage(page);
          },
        ),
        ]
        : null,
      ),
      body:Stack(
        children: <Widget>[
          PDFView(
            filePath: selectedPdfPath,
            autoSpacing: false,
            swipeHorizontal: true,
            enableSwipe: true,
            pageSnap: false,
            pageFling: true,
            onRender: (pages) => setState(() => this.pages = pages),
            onViewCreated: (controller) =>
                setState(() => this.controller = controller),
            onPageChanged: (indexPage, _) =>
                setState(() => this.indexPage = indexPage),
            //  errorMessage.isEmpty
          ),
        ],
      ),
    );
  }

  Future <String> get _localPath async {
    final directory = await getApplicationDocumentsDirectory();
    return directory.path;
  }

  Future<File> get _localFile async{
    final path = await _localPath;
    return File('$path/guidelines.pdf');
  }

  Future<File> writeToLocal(Uint8List bytes) async {
    final file = await _localFile;
    return file.writeAsBytes(bytes);
  }

}

Answer 1

我遇到了同样的问题。试试这个小部件：

import 'dart:io';
import 'dart:typed_data';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:logger/logger.dart';
import 'package:path_provider/path_provider.dart';
import 'package:pilot_dispatch_app/tools/fs_utils.dart';
import 'package:share/share.dart';
import 'package:syncfusion_flutter_pdfviewer/pdfviewer.dart';

class PdfFromUrl extends StatefulWidget {
  final String url;

  const PdfFromUrl({Key? key, required this.url}) : super(key: key);
  @override
  _PdfFromUrlState createState() => _PdfFromUrlState();
}

class _PdfFromUrlState extends State<PdfFromUrl> {
  //String pathPDF = "";
  String remotePDFpath = "";

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return PDFScreen(path: widget.url);
  }
}

class PDFScreen extends StatefulWidget {
  final String? path;

  PDFScreen({Key? key, this.path}) : super(key: key);

  _PDFScreenState createState() => _PDFScreenState();
}

class _PDFScreenState extends State<PDFScreen> with WidgetsBindingObserver {
  // final Completer<PDFViewController> _controller =
  //     Completer<PDFViewController>();
  int? pages = 0;
  int? currentPage = 0;
  bool isReady = false;
  String errorMessage = '';
  String? getFileName(String? pdfUrl) {
    if (pdfUrl != null) {
      var result = pdfUrl.substring(pdfUrl.lastIndexOf('/') + 1);
      if (result.contains('?')) {
        result = result.substring(0, result.lastIndexOf('?'));
      }
      return result;
    }
  }

  @override
  Widget build(BuildContext context) {
    var title = getFileName(widget.path);
    return Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: true,
        title: Text(title!),
        leading: IconButton(
          icon: Icon(Icons.arrow_back),
          onPressed: () => Navigator.pop(context, false),
        ),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.share),
            onPressed: () async {
              try {
                final pdfUint8List = await FsUtils.getUint8ListFromUrl(
                  widget.path!,
                );
                if (pdfUint8List != null) {
                  final file = await writeToLocal(pdfUint8List);
                  Share.shareFiles([file.path]);
                }
              } catch (e) {
                Logger().e(
                  e.toString(),
                );
              }
              //Share.share(widget.path!);
            },
          ),
        ],
      ),
      body: Container(
        child: SfPdfViewer.network(
          widget.path!,
          //'https://cdn.syncfusion.com/content/PDFViewer/flutter-succinctly.pdf',
          enableDocumentLinkAnnotation: false,
        ),
      ),
    );
  }
}

Future<String> get _localPath async {
  final directory = await getApplicationDocumentsDirectory();

  return directory.path;
}

Future<File> get _localFile async {
  final path = await _localPath;
  return File('$path/guidelines.pdf');
}

Future<File> writeToLocal(Uint8List bytes) async {
  final file = await _localFile;
  // Write the file
  return file.writeAsBytes(bytes);
}