Flutter:如何使用“多图像拾取器”来降低图像质量并输出为“文件”？

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Multi Image Picker Example')),
        body: ImagePickerExample(),
      ),
    );
  }
}

class ImagePickerExample extends StatefulWidget {
  @override
  _ImagePickerExampleState createState() => _ImagePickerExampleState();
}

class _ImagePickerExampleState extends State<ImagePickerExample> {
  List<XFile> _images = [];

  Future<void> _pickImages() async {
    try {
      final pickedFiles = await ImagePicker().pickMultiImage(source: ImageSource.gallery);
      if (pickedFiles != null) {
        setState(() {
          _images.addAll(pickedFiles.map((e) => XFile(e.path)));
        });
      }
    } catch (e) {
      print(e);
    }
  }

  Future<void> _processImages() async {
    for (var image in _images) {
      final bytes = await image.readAsBytes();
      final codec = await instantiateImageCodec(bytes);
      final frame = await codec.getNextFrame();
      final resizedImage = await Image(image: frame.image).resize(800, 600);
      final resizedBytes = await resizedImage.toByteData(format: ImageByteFormat.jpeg);
      final quality = 50; // 设置图像质量，范围为 0-100
      final jpegEncoder = JPEGEncoder.withQuality(quality);
      final encodedBytes = jpegEncoder.encodeBytes(resizedBytes!.buffer.asUint8List());
      final outputFile = File('${DateTime.now()}.jpg');
      await outputFile.writeAsBytes(encodedBytes);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        ElevatedButton(
          onPressed: _pickImages,
          child: Text('Pick Images'),
        ),
        ElevatedButton(
          onPressed: _images.isNotEmpty ? _processImages : null,
          child: Text('Process Images'),
        ),
        Expanded(
          child: ListView.builder(
            itemCount: _images.length,
            itemBuilder: (context, index) {
              return ListTile(
                title: Text(_images[index].name),
              );
            },
          ),
        ),
      ],
    );
  }
}