To save and open a PDF file that is received in a base64 format

main.dart

// ignore_for_file: use_build_context_synchronously

import 'dart:convert';
import 'dart:io';
import 'package:advance_pdf_viewer2/advance_pdf_viewer.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:pdf_viewer_project/pages/pdf_viewer_page.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter PDF Viewer',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final String base64String =
      "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";

  Future<File> saveBase64ToFile(String base64String, String fileName) async {
    try {
      final directory = await getApplicationDocumentsDirectory();
      final filePath = '${directory.path}/$fileName';
      final bytes = base64Decode(base64String);
      final file = File(filePath);
      await file.writeAsBytes(bytes);
      return file;
    } catch (e) {
      print("Error saving file: $e");
      rethrow;
    }
  }

  Future<void> saveAndOpenPdf(String base64String, String fileName, BuildContext context) async {
    try {
      final file = await saveBase64ToFile(base64String, fileName);
      Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => PdfViewerPage(filePath: file.path),
        ),
      );
    } catch (e) {
      print("Error opening PDF: $e");
      rethrow;
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Home Page"),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: () async {
            try {
              await saveAndOpenPdf(base64String, "example.pdf", context);
            } catch (e) {
              if (kDebugMode) {
                print("Error: $e");
              }
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(content: Text("Error opening PDF: $e")),
              );
            }
          },
          child: const Text("Open PDF"),
        ),
      ),
    );
  }
}




// 'JVBERi0xLjEKJcKlwrHDqwoKMSAwIG9iagogIDw8IC9UeXBlIC9DYXRhbG9nCiAgICAgL1BhZ2VzIDIgMCBSCiAgPj4KZW5kb2JqCgoyIDAgb2JqCiAgPDwgL1R5cGUgL1BhZ2VzCiAgICAgL0tpZHMgWzMgMCBSXQogICAgIC9Db3VudCAxCiAgICAgL01lZGlhQm94IFswIDAgMzAwIDE0NF0KICA+PgplbmRvYmoKCjMgMCBvYmoKICA8PCAgL1R5cGUgL1BhZ2UKICAgICAgL1BhcmVudCAyIDAgUgogICAgICAvUmVzb3VyY2VzCiAgICAgICA8PCAvRm9udAogICAgICAgICAgIDw8IC9GMQogICAgICAgICAgICAgICA8PCAvVHlwZSAvRm9udAogICAgICAgICAgICAgICAgICAvU3VidHlwZSAvVHlwZTEKICAgICAgICAgICAgICAgICAgL0Jhc2VGb250IC9UaW1lcy1Sb21hbgogICAgICAgICAgICAgICA+PgogICAgICAgICAgID4+CiAgICAgICA+PgogICAgICAvQ29udGVudHMgNCAwIFIKICA+PgplbmRvYmoKCjQgMCBvYmoKICA8PCAvTGVuZ3RoIDU1ID4+CnN0cmVhbQogIEJUCiAgICAvRjEgMTggVGYKICAgIDAgMCBUZAogICAgKEhlbGxvIFdvcmxkKSBUagogIEVUCmVuZHN0cmVhbQplbmRvYmoKCnhyZWYKMCA1CjAwMDAwMDAwMDAgNjU1MzUgZiAKMDAwMDAwMDAxOCAwMDAwMCBuIAowMDAwMDAwMDc3IDAwMDAwIG4gCjAwMDAwMDAxNzggMDAwMDAgbiAKMDAwMDAwMDQ1NyAwMDAwMCBuIAp0cmFpbGVyCiAgPDwgIC9Sb290IDEgMCBSCiAgICAgIC9TaXplIDUKICA+PgpzdGFydHhyZWYKNTY1CiUlRU9GCg=='

pdf_viewer_page.dart

import 'dart:io';

import 'package:advance_pdf_viewer2/advance_pdf_viewer.dart';
import 'package:flutter/material.dart';

class PdfViewerPage extends StatefulWidget {
  final String filePath;

  PdfViewerPage({required this.filePath});

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

class _PdfViewerPageState extends State<PdfViewerPage> {
  bool _isLoading = true;
  late PDFDocument document;

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

  loadDocument() async {
    try {
      document = await PDFDocument.fromFile(File(widget.filePath));
      setState(() {
        _isLoading = false;
      });
    } catch (e) {
      print("Error loading document: $e");
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text("Error loading PDF: $e")),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("PDF Viewer"),
      ),
      body: _isLoading ? const Center(child: CircularProgressIndicator()) : PDFViewer(document: document),
    );
  }
}

pubspec.yaml

#Add these as dependencies along with the other configurations that are present in the pubspec.yaml file

dependencies:
  flutter:
    sdk: flutter
  advance_pdf_viewer2: ^2.0.1
  path_provider: ^2.0.8