使用 httpclient 和 asynctask 取消文件下载 [英] Cancelling file download with httpclient and asynctask

问题描述

在我的应用程序中，我需要从 url 位置下载文件.我想在对话框中(或可选地在通知区域中)显示下载进度.我在这个主题上遇到了几个很好的资源(比如 http://progrnotes.blogspot.com/2010/09/c-android.html).不幸的是，所有示例都没有明确说明如何根据用户请求正确取消下载.所以我的问题其实很简单:

In my app I need to download files from url locations. I want to display progress of the download in a dialogbox (or optionally in the notification area). I've come across several good resources on this subject (something like http://progrnotes.blogspot.com/2010/09/c-android.html). Unfortunately, all the examples don't provide a clear indication on how to properly cancel a download per the user's request. So my question is actually quite simple:

给定一个异步任务，它在后台下载文件(使用 httpclient)并显示一个带有下载进度和取消按钮的对话框，我如何在按下按钮时取消下载并停止后台任务?

Given an asynctask which downloads the file in the background (with httpclient) and displays a dialogbox with download progress and a cancel button, how do I can cancel the download and stop the background task when the button is pressed?

我知道终止线程通常不是一个好主意，因此我可能需要在后台线程中使用取消"变量.如何将按钮的停止信号传递给异步任务?

I know killing threads is generally not a good idea, so I will probably need to work with a 'cancel'-variable in my background thread. How do I communicate a stop signal from the button to the asynctask?

问候，伊沃

推荐答案

让你的按钮调用 AsyncTask.cancel(true) 然后从内部检查 isCancelled()代码>doInBackground(Params... params).通过这种方式，您可以通知后台线程应该取消下载，并且您可以采取适当的步骤来停止下载.

Have your button call AsyncTask.cancel(true) and then check isCancelled() from inside doInBackground(Params... params). In this manner, you can communicate to the background thread that the download should be cancelled, and you can take the appropriate steps to stop it.

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