HarmonyOS 鸿蒙Next 线程间如何共享类对象（引用方式）

不支持通过全局函数getContext获取上下文，只能通过传递参数的方法将context传递过去。

参考：

[@Concurrent](/user/Concurrent)

function downloadFile(context: Context) {

 let downloadTask: request.DownloadTask;

 try {

   let filePath = context.cacheDir + “/” + systemDateTime.getTime() + “.png”;

   console.info("[downloadFile] filePath :" + filePath)

   request.downloadFile(context, {

     url: ‘https://www.baidu.com/img/flexible/logo/pc/peak-result.png’,

     filePath: filePath

   }, (err: BusinessError, data: request.DownloadTask) => {

     if (err) {

       console.error([downloadFile] Failed to request the download. Code: ${err.code}, message: ${err.message});

       return;

     }

     downloadTask = data;

     let completeCallback = () => {

       console.info(’[downloadFile] Download task completed.’);

     };

     let pauseCallback = () => {

       console.info(’[downloadFile] Download task pause.’);

     };

     let removeCallback = () => {

       console.info(’[downloadFile] Download task remove.’);

     };

     let failCallback = (err: number) => {

       console.error([downloadFile] Failed to download the task. Code: ${err});

     };

     downloadTask.on(‘fail’, failCallback);

     downloadTask.on(‘remove’, removeCallback);

     downloadTask.on(‘pause’, pauseCallback);

     downloadTask.on(‘complete’, completeCallback);

   });

 } catch (err) {

   console.error([downloadFile] Failed to request the download. err: ${JSON.stringify(err.message)});

 }

}

taskpoolContext() {

 let task: taskpool.Task = new taskpool.Task(downloadFile, getContext(this));

 taskpool.execute(task)

}