flutter_image_compress errors example code issue directory

import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:io';

import 'package:flutter/services.dart';
import 'package:flutter_image_compress/flutter_image_compress.dart';
import 'package:simple_permissions/simple_permissions.dart';

 import 'package:path_provider/path_provider.dart';
 import 'package:image_picker/image_picker.dart';

void main() => runApp(new MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {




  @override
  void initState() {
    super.initState();
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> compress() async {
    var img = AssetImage("images/background1.jpg");
    print("pre compress");
    var config = new ImageConfiguration();

    AssetBundleImageKey key = await img.obtainKey(config);
    final ByteData data = await key.bundle.load(key.name);

    var beforeCompress = data.lengthInBytes;
    print("beforeCompress = $beforeCompress");

    var result =
    await FlutterImageCompress.compressWithList(data.buffer.asUint8List());

    print("after = ${result?.length ?? 0}");
  }

  ImageProvider provider;

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new Scaffold(
        appBar: new AppBar(
          title: const Text('Plugin example app'),
        ),
        body: new Center(
          child: Column(
            children: <Widget>[
              Image(
                image: provider ?? AssetImage("images/background1.jpg"),
              ),
              FlatButton(
                child: Text('capture'),
                onPressed: _capture,
              ),
              FlatButton(
                child: Text('file image'),
                onPressed: getFileImage,
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          child: Icon(Icons.computer),
          onPressed: _capture,
        ),
      ),
    );
  }

  Future<Directory> getTemporaryDirectory() async {
    return Directory.current;
  }

  Future _capture() async {

//    final dir = await getTemporaryDirectory();
    final tempDir = await getTemporaryDirectory();
    String path = tempDir.path.toString();

    requestPermission() async {
      final res = await SimplePermissions.requestPermission(Permission.WriteExternalStorage);
      print("permission request result is " + res.toString());
    }
    requestPermission();



    var img = AssetImage("images/background1.jpg");
    print("pre compress");
    var config = new ImageConfiguration();

    AssetBundleImageKey key = await img.obtainKey(config);
    final ByteData data = await key.bundle.load(key.name);



    print(path);

    File file = File("${path}/test.png");
    file.writeAsBytesSync(data.buffer.asUint8List());

    List<int> list = await testCompressFile(file);
    ImageProvider provider = MemoryImage(list);
    this.provider = provider;
    setState(() {});
    return;
  }



  void getFileImage() async {
    var img = AssetImage("images/background1.jpg");
    print("pre compress");
    var config = new ImageConfiguration();

    AssetBundleImageKey key = await img.obtainKey(config);
    final ByteData data = await key.bundle.load(key.name);
    var dir = await getTemporaryDirectory();

    File file = File("${dir.absolute.path}/test.png");
    file.writeAsBytesSync(data.buffer.asUint8List());

    var targetPath = dir.absolute.path + "/temp.png";
    var imgFile = await testCompressAndGetFile(file, targetPath);

    provider = FileImage(imgFile);
    setState(() {});
  }

  Future<List<int>> testCompressFile(File file) async {
    var result = await FlutterImageCompress.compressWithFile(
      file.absolute.path,
      minWidth: 2300,
      minHeight: 1500,
      quality: 94,
    );
    print(file.lengthSync());
    print(result.length);
    return result;
  }

  Future<File> testCompressAndGetFile(File file, String targetPath) async {
    var result = await FlutterImageCompress.compressAndGetFile(
        file.absolute.path, targetPath,
        quality: 88);

    print(file.lengthSync());
    print(result.lengthSync());

    return result;
  }

  Future<List<int>> testCompressAsset(String assetName) async {
    var list = await FlutterImageCompress.compressAssetImage(
      assetName,
      minHeight: 1920,
      minWidth: 1080,
      quality: 96,
    );

    return list;
  }

  Future<List<int>> testComporessList(List<int> list) async {
    var result = await FlutterImageCompress.compressWithList(
      list,
      minHeight: 1920,
      minWidth: 1080,
      quality: 96,
    );
    print(list.length);
    print(result.length);
    return result;
  }

  void writeToFile(List<int> list, String filePath) {
    var file = File(filePath);
    file.writeAsBytes(list, flush: true, mode: FileMode.write);
  }
}