FilePickerResult? result = await FilePicker.platform.pickFiles();

if (result != null) {
  File file = File(result.files.single.path!);
} else {
  // User canceled the picker
}

FilePickerResult? result = await FilePicker.platform.pickFiles(allowMultiple: true);

if (result != null) {
  List<File> files = result.paths.map((path) => File(path!)).toList();
} else {
  // User canceled the picker
}

FilePickerResult? result = await FilePicker.platform.pickFiles(
  type: FileType.custom,
  allowedExtensions: ['jpg', 'pdf', 'doc'],
);

String? selectedDirectory = await FilePicker.platform.getDirectoryPath();

if (selectedDirectory == null) {
  // User canceled the picker
}

String? outputFile = await FilePicker.platform.saveFile(
  dialogTitle: 'Please select an output file:',
  fileName: 'output-file.pdf',
);

if (outputFile == null) {
  // User canceled the picker
}

FilePickerResult? result = await FilePicker.platform.pickFiles();

if (result != null) {
  PlatformFile file = result.files.first;

  print(file.name);
  print(file.bytes);
  print(file.size);
  print(file.extension);
  print(file.path);
} else {
  // User canceled the picker
}

FilePickerResult? result = await FilePicker.platform.pickFiles();

if (result != null) {
  // All files
  List<XFile> xFiles = result.xFiles;

  // Individually
  XFile xFile = result.files.first.xFile;
} else {
  // User canceled the picker
}

FilePickerResult? result = await FilePicker.platform.pickFiles();

if (result != null) {
  Uint8List fileBytes = result.files.first.bytes;
  String fileName = result.files.first.name;
  
  // Upload file
  await FirebaseStorage.instance.ref('uploads/$fileName').putData(fileBytes);
}