1. 使用uni.downloadFile,但是注意下载图片的地址里的域名，需要在微信公众平台里面的downloadFile合法域名进行配置。

export default function downloadAndCacheImage(imageUrl, name) {return new Promise((resolve, reject) => {console.log("imageUrl", imageUrl, name)// 检查本地缓存的更新时间let lastUpdateTime = uni.getStorageSync('lastUpdateTime');let currentDate = new Date().getTime();// if (!lastUpdateTime || currentDate - lastUpdateTime >= 24 * 60 * 60 * 1000) {// 下载最新的背景图片到本地uni.downloadFile({url: imageUrl,success: (res) => {uni.saveFile({tempFilePath: res.tempFilePath,success: (saveRes) => {// 保存图片路径到本地缓存uni.setStorageSync(name, saveRes.savedFilePath);uni.setStorageSync('lastUpdateTime', currentDate);console.log("缓存成功", res)}});},fail: (res) => {console.log("缓存失败", res)}});// }});}// 缓存图片
downloadAndCacheImage('https://www.com.jpg', 'search_page1')
this.list[2].img=uni.getStorageSync('search_page1')