如何获取文件的网络URI正从Android的下载管理器下载 [英] How to get the network uri of a file being downloaded from the Download Manager in Android

问题描述

我写一个应用程序，其中我想如果下载已开始检测和检索下载文件的URI，然后取消从下载管理器中下载。我这样做，这样我可以在别处发送此URI。

I am writing an application wherein I want to detect if a download has started and retrieve the URI of the file being downloaded and then cancel the download from the Download Manager. I am doing this so that I can send this URI somewhere else.

麻烦的是，当下载通过查询下载管理器开始我可以检测，但有下载的方法还是在下载管理器中的常量变量从中我还可以得到该文件的URL

The trouble is that I can detect when a download begins by querying the Download Manager, but is there a method or a constant variable in Download Manager from which I can also get the URL of the file being downloaded

推荐答案

确定其怪异的回答自己的问题，但我终于想通了如何做到这一点。有下载管理类android.app，其中存储发起的所有HTTP下载及其状态的列表。这些可以根据下载是否为正在运行，待处理，PAUSED等被过滤掉。

Ok its weird answering your own question, but I finally figured out how to do this. There is a DownloadManager class in android.app, which stores a list of all http downloads initiated and their statuses. These can be filtered out based on whether the download is 'RUNNING', 'PENDING', 'PAUSED' and so on.

这个名单可以读入一光标和结果的列中的一个是COLUMN_URI'，这是从文件正在下载，其中的URL。样本code，其中我已经用它作为如下：

This list can be read into a cursor and one of the columns of the result is 'COLUMN_URI', which is the url from where the file is being downloaded. A sample code where I have used it is as given below:

public void readDownloadManager() {
                DownloadManager.Query query = null;
                DownloadManager downloadManager = null;
                Cursor c = null;
                try {
                    query = new DownloadManager.Query();
                    downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);

                    //Just for testing I initiated my own download from this url. When an http
                    // reuest for this url is made, since download is taking place, it gets saved in
                    // the download manager.
                    Request request = new Request(Uri.parse("http://ocw.mit.edu/courses" +
                            "/aeronautics-and-astronautics/16-100-aerodynamics-fall-2005" +
                            "/lecture-notes/16100lectre1_kvm.pdf"));
                    downloadManager.enqueue(request);
                    query.setFilterByStatus(DownloadManager.STATUS_PENDING);
                    c = downloadManager.query(query);

                    if(true){
                        int statusColumnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
                        int urlColumnIndex = c.getColumnIndex(DownloadManager.COLUMN_URI);
                        long downloadProcessIdColumnNo = c.getColumnIndex(DownloadManager.COLUMN_ID);
                        Log.d("Column Count", ((Integer)c.getCount()).toString());
                        if(c.getCount() > 0){
                            String url="";
                            c.moveToLast();
                            if(c.isLast()){
                                url = c.getString(urlColumnIndex);
                                downloadManager.remove(downloadProcessIdColumnNo);
                                Log.d("Count after remove", ((Integer)c.getCount()).toString());
                            }
                            Log.d("After", "Stopped Working");

                            //Here I am sending the url to another activity, where I can work with it.
                            Intent intent = new Intent(EasyUploadMainMenu.this, EasyUploadActivity.class);
                            Bundle b = new Bundle();
                            b.putString("url", url);
                            intent.putExtras(b);
                            startActivity(intent);
                            Log.d("url:", url);
                        }
                    }

                } catch (NullPointerException ex) {
                    ex.printStackTrace();
                }
            }

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