How to get ByteData from a File - dart

Question

I want to convert a File to a ByteData object in flutter.
Something like this:
import 'dart:io';
File file = getSomeCorrectFile(); //This file is correct
ByteData bytes = ByteData(file.readAsBytesSync()); //Doesnt compile
return bytes;
I understood that ByteData constructor receives the length of the amount of bytes and initialize them with 0, so I could do something like ByteData(file.readAsBytesStync().length); but then how do I fill them?
What am I missing?

Answer 1

In Dart 2.5.0 or later, I believe that the following should work:
import 'dart:io';
import 'dart:typed_data';
...
File file = getSomeCorrectFile();
Uint8List bytes = file.readAsBytesSync();
return ByteData.view(bytes.buffer);
(Prior to Dart 2.5.0, the file.readAsBytesSync() line should be:
Uint8List bytes = file.readAsBytesSync() as Uint8List;
File.readAsBytes/File.readAsBytesSync used to be declared to return a List<int>, but the returned object was actually a Uint8List subtype.)
Once you have the bytes as a Uint8List, you can extract its ByteBuffer and construct a ByteData from that.

Answer 2

in Dart 2.9:
import 'dart:io';
import 'dart:typed_data';
final file = getSomeCorrectFile(); // File
final bytes = await file.readAsBytes(); // Uint8List
final byteData = bytes.buffer.asByteData(); // ByteData
return byteData;

Answer 3

this is worked for me ...
Uint8List uint8list = Uint8List.fromList(File(path).readAsBytesSync())

Answer 4

Try this:
File file = getSomeCorrectFile();
ByteData bytes = await file.readAsBytes().then((data) => ByteData.view(data as ByteBuffer));
return bytes;

Answer 5

here is my class to handle this:
import 'dart:io';
import 'dart:typed_data';
class FileHandler {
final String _filePath;
FileHandler(this._filePath);
Future<Uint8List> _readToBytes() async {
var file = File.fromUri(Uri.parse(_filePath));
return await file.readAsBytes();
}
Future<Map<String, dynamic>> get data async {
var byte = await _readToBytes();
var ext = _filePath.split('.').last;
return {'byte': byte, 'extension': ext};
}
}

Answer 6

here is my class to handle this:
import 'dart:io';
import 'dart:typed_data';
class FileHandler {
final String _filePath;
FileHandler(this._filePath);
Future<Uint8List> _readToBytes() async {
var file = File.fromUri(Uri.parse(_filePath));
return await file.readAsBytes();
}
Future<Map<String, dynamic>> get data async {
var byte = await _readToBytes();
var ext = _filePath.split('.').last;
return {'byte': byte, 'extension': ext};
}
}