0 .Thanks
Android系统下载管理DownloadManager功能介绍及使用示例
1 .概述
DowanloadManger：系统的服务，系统开放给第三方应用使用的类，用于管理下载。
DownloadManager.Query：用来查询下载信息
DownloadManager.Request：用来请求一个下载
2 .DownloadManager.Request
addRequestHeader(String header, String value)
Add an HTTP header to be included with the download request.
添加一个Http的头到下载的请求。
allowScanningByMediaScanner()
If the file to be downloaded is to be scanned by MediaScanner, this method should be called before enqueue(Request) is called.
可以理解为，允许媒体的扫描。需要在任务开始前调用。
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setAllowedNetworkTypes(int flags)
Restrict the types of networks over which this download may proceed.
限制什么类型的网络可以下载：-
DownloadManager.Request.NETWORK_MOBILE-Wifi或者移动网络可以下载 -
DownloadManager.Request.NETWORK_WIFI-只允许Wifi的环境下，下载。
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setAllowedOverMetered(boolean allow)计量网络下载？不懂。默认允许。setAllowedOverRoaming(boolean allowed)允许漫游网络？默认运行。setDescription(CharSequence description)
Set a description of this download, to be displayed in notifications (if enabled)
设置下载的描述，会显示在通知栏，如果允许的话。setDestinationInExternalFilesDir(Context context, String dirType, String subPath)
Set the local destination for the downloaded file to a path within the application's external files directory (as returned by getExternalFilesDir(String).
设置文件的存放目录。这个方法设置的是，应用程序内能访问的。其可以用的路径：context.getExternalFilesDir(String).setDestinationInExternalPublicDir(String dirType, String subPath)
Set the local destination for the downloaded file to a path within the public external storage directory (as returned by getExternalStoragePublicDirectory(String)).
设置文件的存放目录。这个方法设置的是，程序的外部存储。其可以用的路径：Environment.getExternalFilesDir(String).
或者，可以自定义。setDestinationUri(Uri uri)
Set the local destination for the downloaded file.
设置下载地址。为uri.setMimeType(String mimeType)
Set the MIME content type of this download.
设置下载类型：MIME 参考手册
apk的Mime:application/vnd.android-
setNotificationVisibility(int visibility)
Control whether a system notification is posted by the download manager while this download is running or when it is completed.
设置通知栏是否显示和显示的规则：- VISIBILITY_HIDDEN ：不显示在通知栏
- VISIBILITY_VISIBLE ：显示在通知栏，下载完成后，消失。
- VISIBILITY_VISIBLE_NOTIFY_COMPLETED ：显示在通知栏，下载完成后，也显示。
- VISIBILITY_VISIBLE_NOTIFY_ONLY_COMPLETION ：显示在通知栏，只是完成后显示。下载的时候，不显示。
setRequiresCharging(boolean requiresCharging)需要插入才下载？不懂setRequiresDeviceIdle(boolean requiresDeviceIdle)空闲的时候才下载？setTitle(CharSequence title)
设置下载题目，显示在通知栏，如果可以的话。setVisibleInDownloadsUi(boolean isVisible)
Set whether this download should be displayed in the system's Downloads UI.
设置下载的地址URI是否能在通知栏上可见。
3 .DownloadManager.Query
查询任务。
setFilterById(long... ids)
Include only the downloads with the given IDs.
根据下载的ID返回任务：DownloadManager.QuerysetFilterByStatus(int flags)
include only downloads with status matching any the given status flags.
根据Flags去过滤返回：DownloadManager.Query
查询可以通过：
private void queryDownloadStatus() {
DownloadManager.Query query = new DownloadManager.Query();
final DownloadManager downloadManager= (DownloadManager)
this.getSystemService(Context.DOWNLOAD_SERVICE);
query.setFilterById(TaskID);
Cursor c = downloadManager.query(query);
if(c.moveToFirst()) {
int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
switch(status) {
case DownloadManager.STATUS_PAUSED:
case DownloadManager.STATUS_PENDING:
case DownloadManager.STATUS_RUNNING:
case DownloadManager.STATUS_SUCCESSFUL:
}
}
}
去查询任务的状态。
下载的监听：
/**
* 得到下载的状态
* @param context 上下文
* @param downloadId ID
* @return 0 : 已经下载的量(bytes) , 1 : 总的大小， 2 ： 下载的状态
*/
public static int[] getBytesAndStatus(Context context, long downloadId) {
int[] bytesAndStatus = new int[] { -1, -1, -1 };
DownloadManager.Query query = new DownloadManager.Query()
.setFilterById(downloadId);
DownloadManager downloadManager = (DownloadManager)
context.getSystemService(Context.DOWNLOAD_SERVICE);
Cursor c = null;
try {
c = downloadManager.query(query);
if (c != null && c.moveToFirst()) {
bytesAndStatus[0] = c.getInt(c.getColumnIndexOrThrow(DownloadManager
.COLUMN_BYTES_DOWNLOADED_SO_FAR));
bytesAndStatus[1] = c.getInt(c.getColumnIndexOrThrow(DownloadManager
.COLUMN_TOTAL_SIZE_BYTES));
bytesAndStatus[2] = c.getInt(c.getColumnIndex(DownloadManager
.COLUMN_STATUS));
}
} finally {
if (c != null) {
c.close();
}
}
return bytesAndStatus;
}
