【flutter压缩Uint8List图片大小】

如果没有引入flutter_cache_manager库需要引入

例如flutter_cache_manager: 3.3.0

import 'package:image/image.dart' as image;
import 'package:flutter_cache_manager/flutter_cache_manager.dart';

_compressImage(String mirrorImage){
	Uint8List imageBytes;
    if(mirrorImage.startsWith('http')){
      final File file = await DefaultCacheManager().getSingleFile(mirrorImage);
      final image.Image thumbnail = image.decodeImage(file.readAsBytesSync());
      imageBytes = thumbnail.getBytes();
    }else{
      imageBytes = await File(mirrorImage).readAsBytes();
    }
 	print("图片初始大小：${imageBytes .length/ 1024 /1024}MB");
    if (imageBytes.length > 1024 * 1024 * 0.5) {
      int _quality = 90;
      while(imageBytes.length > 1024 * 1024 * 0.5 && _quality>0){
        imageBytes = Uint8List.fromList(image.encodeJpg(thumbnail,quality: _quality));
        _quality -= 2;
      }
      print("图片压缩后大小：${thumbData.length} ${thumbData.length/ 1024 / 1024}MB");
    }
    }