基于WebDownloadDelegate的PDF下载预览

try { 
  if (event) { 
    const webResponse = new WebResourceResponse(); 
    let url = event.request.getRequestUrl() 
    let headers = event.request.getRequestHeader() 
    if(headers['content-disposition']){ 
      AlertDialog.show({ 
        title: '文件下载', cancel: () => { 
          console.log('取消下载'); 
        }, 
        message: '是否下载', confirm: { 
          value: '确认', action: () => { 
            this.setDownloadDelegate() 
            this.controller.startDownload('https://example.com'); 
          } 
        }, 
 
      }) 
    } 
  } 
}

setDownloadDelegate() { 
  try { 
    this.delegate.onBeforeDownload((webDownloadItem: web_webview.WebDownloadItem) => { 
      console.log('will start a download'); 
      // 传入一个下载路径（沙溪路径），并开始下载。 
      webDownloadItem.start((getContext(this) as common.UIAbilityContext).filesDir + '/test.pdf'); 
    }) 
    // 下载过程中的回调，通过该回调的参数可以了解下载进度等信息。 
    this.delegate.onDownloadUpdated((webDownloadItem: web_webview.WebDownloadItem) => { 
      console.log('download update guid: ' + webDownloadItem.getGuid()); 
    }) 
    // 下载失败的通知。 
    this.delegate.onDownloadFailed((webDownloadItem: web_webview.WebDownloadItem) => { 
      console.log('download failed guid: ' + webDownloadItem.getGuid()); 
    }) 
    // 下载完成的通知。 
    this.delegate.onDownloadFinish(async (webDownloadItem: web_webview.WebDownloadItem) => { 
      console.log('download finish guid: ' + webDownloadItem.getGuid()); 
      let file = fs.statSync((getContext(this) as common.UIAbilityContext).filesDir + '/test.pdf') 
      console.log('testTag - size: ' + file.size + 'path:'); 
    }) 
    let fileuri = 'file://’ + (getContext(this) as common.UIAbilityContext).filesDir + ‘/test.pdf' 
    console.log('testTag - ' + fileuri); 
    this.controller.setDownloadDelegate(this.delegate); 
    web_webview.WebDownloadManager.setDownloadDelegate(this.delegate) 
    this.controller.loadUrl(fileuri) 
  } catch (error) { 
    console.log(JSON.stringify(error)) 
  } 
}

let httpRequest = http.createHttp(); 
let promise = httpRequest.request(url, { 
  method: http.RequestMethod.GET, 
  connectTimeout: 60000, 
  readTimeout: 60000, 
  header:headers 
}); 
promise.then((data:http.HttpResponse) => { 
  let result = data?.result as ArrayBuffer 
  webResponse.setResponseCode(200); 
  webResponse.setReasonMessage('OK'); 
  webResponse.setResponseData(result); 
  webResponse.setResponseEncoding('UTF_8') 
}).catch((err:Error) => { 
  console.info('error:' + JSON.stringify(err)); 
});