network_file_cached 0.0.7

A flutter library to download and cache files in the cache directory of the app.

Usage

Usage example with PDFView to display cached pdf files.

class FileCacheSample extends StatefulWidget {
  const FileCacheSample({super.key, required this.url});

  final String url;

  @override
  State<FileCacheSample> createState() => _FileCacheSampleState();
}

class _FileCacheSampleState extends State<FileCacheSample> {
  Future<File>? file;

  @override
  void initState() {
    super.initState();
    file = getFile();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Plugin example apps'),
      ),
      body: FutureBuilder(
        future: file,
        builder: (context, snapshot) {
          if (snapshot.hasData) {
            return PDFView(
              pdfData: snapshot.data?.readAsBytesSync(),
            );
          }
          if (snapshot.hasError) {
            return Text(snapshot.error.toString());
          }
          return const Text('LOADING...');
        },
      ),
    );
  }

  Future<File> getFile() {
    return NetworkFileCached.downloadFile(widget.url);
  }
}

---

Usage example with loading indicator to display cached pdf files.

await NetworkFileCached.downloadFile(url, onReceiveProgress: (rcv, total) {
      setState(() {
        progress = ((rcv / total) * 100);
      });
    }).then((value) {
      setState(() {
        file = value;
      });
    }).onError((error, stackTrace) {
      setState(() {
        errorMessage = error.toString();
      });
      throw Exception(error);
    });

Full code

class FileCacheLoadingIndicator extends StatefulWidget {
  const FileCacheLoadingIndicator({super.key, required this.url});

  final String url;

  @override
  State<FileCacheLoadingIndicator> createState() =>
      _FileCacheLoadingIndicatorState();
}

class _FileCacheLoadingIndicatorState extends State<FileCacheLoadingIndicator> {
  bool downloading = false;
  double progress = 0;
  bool isDownloaded = false;
  File? file;
  String errorMessage = '';

  @override
  void initState() {
    load(widget.url);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Plugin example apps'),
      ),
      body: errorMessage.isNotEmpty
          ? Center(
              child: Text(errorMessage),
            )
          : file == null
              ? Center(
                  child: Stack(
                    alignment: AlignmentDirectional.center,
                    children: [
                      CircularProgressIndicator(
                        value: (progress == 0) ? null : progress / 100,
                      ),
                      if (progress != 0)
                        Text(
                          progress.toStringAsFixed(0),
                          style: const TextStyle(fontSize: 12),
                        )
                    ],
                  ),
                )
              : PDFView(
                  pdfData: file!.readAsBytesSync(),
                ),
    );
  }

  Future<void> load(String url) async {
    await NetworkFileCached.downloadFile(url, onReceiveProgress: (rcv, total) {
      setState(() {
        progress = ((rcv / total) * 100);
      });
    }).then((value) {
      setState(() {
        file = value;
      });
    }).onError((error, stackTrace) {
      setState(() {
        errorMessage = error.toString();
      });
      throw Exception(error);
    });
  }
}