pdf_view.dart

Future<File> getFileFromAsset(String asset) async {
    try {
      var data = await rootBundle.load(asset);
      var bytes = data.buffer.asUint8List();
      var dir = await getApplicationDocumentsDirectory();
      File file = File("${dir.path}/mi_archivo.pdf");
      File assetFile = await file.writeAsBytes(bytes);
      return assetFile;
    } catch (e) {
      throw Exception("Error al abrir el archivo");
    }
  }

  Future<File> getFileFromUrl(String url) async {
    try {
      var data = await http.get(url);
      var bytes = data.bodyBytes;
      var dir = await getApplicationDocumentsDirectory();
      File file = File("${dir.path}/mi_archivo_online.pdf");
      File urlFile = await file.writeAsBytes(bytes);
      return urlFile;
    } catch (e) {
      throw Exception("Error al abrir el archivo");
    }
  }