fast_download_manager 1.2.0

A lightweight Flutter package for downloading files with real-time progress tracking.

example/lib/main.dart

import 'package:fast_download_manager/fast_download_manager.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Fast Download Manager',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: Colors.blue,
        ),
        useMaterial3: true,
      ),
      home: const DownloadScreen(),
    );
  }
}

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

  @override
  State<DownloadScreen> createState() => _DownloadScreenState();
}

class _DownloadScreenState extends State<DownloadScreen> {
  double progress = 0;

  double speed = 0;

  String speedText = '0 B/s';

  String status = 'Ready';

  String? downloadId;

  bool isDownloading = false;

  bool isCompleted = false;

  Future<void> downloadFile() async {
    final dir = await getApplicationDocumentsDirectory();

    setState(() {
      progress = 0;
      speed = 0;
      speedText = '0 B/s';
      status = 'Starting...';
      isDownloading = true;
      isCompleted = false;
    });

    try {
      final file = await FastDownloader.download(
        url:
            'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf',
        savePath: '${dir.path}/sample.pdf',
        retryCount: 3,
        retryDelay: const Duration(seconds: 2),
        onStart: (id) {
          if (!mounted) return;

          setState(() {
            downloadId = id;
            status = 'Downloading...';
          });
        },
        onProgress: (value) {
          if (!mounted) return;

          setState(() {
            progress = value.progress;
            speed = value.speed;
            speedText = value.speedFormatted;

            status = '${value.receivedFormatted} / '
                '${value.totalFormatted}';
          });
        },
        onStatus: (value) {
          if (!mounted) return;

          setState(() {
            status = _statusText(value);
          });
        },
        onComplete: (file) {
          if (!mounted) return;

          setState(() {
            status = 'Download Completed';
            isCompleted = true;
          });
        },
        onError: (error) {
          if (!mounted) return;

          setState(() {
            status = 'Download Failed';
          });
        },
      );

      if (!mounted) return;

      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            'Saved: ${file.path}',
          ),
        ),
      );
    } on DownloadException catch (e) {
      if (!mounted) return;

      setState(() {
        status = 'Download Failed';
      });

      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(e.message),
        ),
      );
    } catch (e) {
      if (!mounted) return;

      setState(() {
        status = 'Download Failed';
      });

      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(e.toString()),
        ),
      );
    } finally {
      // Don't use `return` inside finally.
      if (mounted) {
        setState(() {
          isDownloading = false;
        });
      }
    }
  }

  void cancelDownload() {
    final id = downloadId;

    if (id == null) {
      return;
    }

    FastDownloader.cancel(id);

    setState(() {
      status = 'Cancelling...';
    });
  }

  String _statusText(
    DownloadStatus status,
  ) {
    switch (status) {
      case DownloadStatus.downloading:
        return 'Downloading...';

      case DownloadStatus.retrying:
        return 'Retrying...';

      case DownloadStatus.completed:
        return 'Download Completed';

      case DownloadStatus.cancelled:
        return 'Download Cancelled';

      case DownloadStatus.failed:
        return 'Download Failed';
    }
  }

  @override
  Widget build(
    BuildContext context,
  ) {
    return Scaffold(
      appBar: AppBar(
        title: const Text(
          'Fast Download Manager',
        ),
        centerTitle: true,
      ),
      body: Center(
        child: Card(
          margin: const EdgeInsets.all(20),
          child: Padding(
            padding: const EdgeInsets.all(20),
            child: SizedBox(
              width: 340,
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const Icon(
                    Icons.download_rounded,
                    size: 70,
                    color: Colors.blue,
                  ),
                  const SizedBox(
                    height: 20,
                  ),
                  LinearProgressIndicator(
                    value: progress,
                  ),
                  const SizedBox(
                    height: 12,
                  ),
                  Text(
                    '${(progress * 100).toStringAsFixed(0)}%',
                    style: const TextStyle(
                      fontWeight: FontWeight.bold,
                      fontSize: 20,
                    ),
                  ),
                  const SizedBox(
                    height: 8,
                  ),
                  Text(
                    status,
                    textAlign: TextAlign.center,
                  ),
                  const SizedBox(
                    height: 8,
                  ),
                  if (isDownloading)
                    Text(
                      speedText,
                      style: const TextStyle(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  const SizedBox(
                    height: 25,
                  ),
                  SizedBox(
                    width: double.infinity,
                    child: ElevatedButton.icon(
                      onPressed: isDownloading ? null : downloadFile,
                      icon: Icon(
                        isDownloading ? Icons.downloading : Icons.download,
                      ),
                      label: Text(
                        isDownloading ? 'Downloading...' : 'Download File',
                      ),
                    ),
                  ),
                  if (isDownloading)
                    Padding(
                      padding: const EdgeInsets.only(
                        top: 10,
                      ),
                      child: SizedBox(
                        width: double.infinity,
                        child: OutlinedButton.icon(
                          onPressed: cancelDownload,
                          icon: const Icon(
                            Icons.cancel,
                          ),
                          label: const Text(
                            'Cancel Download',
                          ),
                        ),
                      ),
                    ),
                  if (isCompleted)
                    const Padding(
                      padding: EdgeInsets.only(
                        top: 20,
                      ),
                      child: Column(
                        children: [
                          Icon(
                            Icons.check_circle,
                            color: Colors.green,
                            size: 45,
                          ),
                          SizedBox(
                            height: 8,
                          ),
                          Text(
                            'File downloaded successfully',
                            style: TextStyle(
                              color: Colors.green,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                        ],
                      ),
                    ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}