/// 使用 File api
import 'dart:io';/// 使用 Uint8List 数据类型
import 'dart:typed_data';/// 图片缓存管理
import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/services.dart';/// 使用 DefaultCacheManager 类（可能无法自动引入，需要手动引入）
import 'package:flutter_cache_manager/flutter_cache_manager.dart';/// 保存文件或图片到本地
import 'package:image_gallery_saver/image_gallery_saver.dart';/// 授权管理
import 'package:permission_handler/permission_handler.dart';class ImageUtil {/// 保存图片到相册////// 默认为下载网络图片，如需下载资源图片，需要指定 [isAsset] 为 `true`。static Future<bool> saveImage(String imageUrl, {bool isAsset: false}) async {try {if (imageUrl == null) throw '保存失败，图片不存在！';/// 权限检测PermissionStatus storageStatus = await Permission.storage.status;if (storageStatus != PermissionStatus.granted) {storageStatus = await Permission.storage.request();if (storageStatus != PermissionStatus.granted) {throw '无法存储图片，请先授权！';}}/// 保存的图片数据Uint8List imageBytes;if (isAsset == true) {/// 保存资源图片ByteData bytes = await rootBundle.load(imageUrl);imageBytes = bytes.buffer.asUint8List();} else {/// 保存网络图片CachedNetworkImage image = CachedNetworkImage(imageUrl: imageUrl);DefaultCacheManager manager =image.cacheManager ?? DefaultCacheManager();Map<String, String> headers = image.httpHeaders;File file = await manager.getSingleFile(image.imageUrl,headers: headers,);imageBytes = await file.readAsBytes();}/// 保存图片final result = await ImageGallerySaver.saveImage(imageBytes);if (result == null || result == '') throw '图片保存失败';return true;} catch (e) {return false;}}/// 获取阿里云上图片缩略图static getOssImageThumbUrl(String url,{double width = 350.0, double height, int quality = 80}) {if (url.contains('?Size=') || url.contains('?size=')) {List<String> strList =url.contains('?Size=') ? url.split('?Size=') : url.split('?size=');url = strList.first;if (height == null) {String sizeStr = strList.last;List<String> sizeList = sizeStr.split('x');double oldImgWid = double.parse(sizeList.first);double oldImgHei = double.parse(sizeList.last);double newImgWid = width;double proportion = oldImgHei / oldImgWid;if (proportion > 1) {proportion = 4 / 3;} else {proportion = 3 / 4;}double newImgHei = proportion * newImgWid;url +='?x-oss-process=image/resize,m_fill,w_${newImgWid.floor()},h_${newImgHei.floor()}/quality,q_$quality';} else {url +='?x-oss-process=image/resize,m_fill,w_${width.floor()},h_${height.floor()}/quality,q_$quality';}} else {if (height != null) {url +='?x-oss-process=image/resize,m_fill,w_${width.floor()},h_${height.floor()}/quality,q_$quality';}}return url;}
}