如何使用Android DownloadManager？ [英] How to use Android DownloadManager?

问题描述

我想使用Android DownloadManager类将文件下载到SDCard：

 请求请求=新请求（Uri.parse（ URL））; 
 request.setDestinationInExternalPublicDir（Environment.DIRECTORY_DOWNLOADS，filename）; // set destination dir 
 long downloadId = downloader.enqueue（request）;但是我总是得到下载状态= 16（STATUS_FAILED），并且原因= 1008（ERROR_CANNOT_RESUME），
  

我已经在清单中包含了android.permission.WRITE_EXTERNAL_STORAGE。

当我注释出

  request.setDestinationInExternalPublicDir（Environment.DIRECTORY_DOWNLOADS，filename）; 
  

并使用默认的下载文件夹，没关系。但是我不知道文件在哪里，我从结果中得到的地方就是这样：

  content：/ / download / my_downloads / 95 
  

我不知道如何将文件复制到SDCard。 p>

我想要的是将文件下载到SDCard 。有人可以帮忙吗？谢谢！

解决方案

您可以从localUri检索文件路径，如下所示：

  public static String getFilePathFromUri（Context c，Uri uri）{
 String filePath = null; 
 if（content.equals（uri.getScheme（）））{
 String [] filePathColumn = {MediaColumns.DATA}; 
 ContentResolver contentResolver = c.getContentResolver（）; 
 
游标cursor = contentResolver.query（uri，filePathColumn，null，
 null，null）; 
 
 cursor.moveToFirst（）; 
 
 int columnIndex = cursor.getColumnIndex（filePathColumn [0]）; 
 filePath = cursor.getString（columnIndex）; 
 cursor.close（）; 
} else if（file.equals（uri.getScheme（）））{
 filePath = new File（uri.getPath（））。getAbsolutePath（）; 
} 
 return filePath; 
} 
  

I want to download a file to SDCard with Android DownloadManager class:

Request request = new Request(Uri.parse(url));
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename); //set destination dir
long downloadId = downloader.enqueue(request);

But I always get download status=16(STATUS_FAILED), and reason=1008(ERROR_CANNOT_RESUME). I have already included android.permission.WRITE_EXTERNAL_STORAGE in the manifest.

When i commented out the

request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename); 

and use the default download folder, it's OK. But I don't know where is the file goes, the localUri I get from the result is something like:

content://downloads/my_downloads/95

I don't know how to copy the file to SDCard.

What I want is download a file to SDCard. Could someone help? Thanks!

解决方案

You can retrieve file path from localUri like this:

public static String getFilePathFromUri(Context c, Uri uri) {
    String filePath = null;
    if ("content".equals(uri.getScheme())) {
        String[] filePathColumn = { MediaColumns.DATA };
        ContentResolver contentResolver = c.getContentResolver();

        Cursor cursor = contentResolver.query(uri, filePathColumn, null,
                null, null);

        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        filePath = cursor.getString(columnIndex);
        cursor.close();
    } else if ("file".equals(uri.getScheme())) {
        filePath = new File(uri.getPath()).getAbsolutePath();
    }
    return filePath;
}

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