HarmonyOS 鸿蒙Next网络文件下载至本地预览出错

首先判断文件是否可预览，而且文件路径是需要转换uri的，预览时还要指定文件类型。

  let uri =  fileUri.getUriFromPath(filePath);
   let uiContext = getContext() ;
   filePreview.canPreview(uiContext, uri).then((result) => {    // 传入支持的文件类型且项目存在时会返回true
     let displayInfo: filePreview.DisplayInfo = {
       x: 100,
       y: 100,
       width: 800,
       height: 800
     };
     let fileInfo: filePreview.PreviewInfo = {
       title: fileName,
       uri: uri,
       mimeType: 'text/html'
     };
     filePreview.openPreview(uiContext, fileInfo, displayInfo).then(() => {
       console.info('Succeeded in opening preview');
     }).catch((err: BusinessError) => {
       console.error(`Failed to open preview, err.code = ${err.code}, err.message = ${err.message}`);
     });

   }).catch((err: BusinessError) => {
     console.error(`Failed to obtain the result of whether it can be previewed, err.code = ${err.code}, err.message = ${err.message}`);
   });