Android下载管理DownloadManager功能扩展和bug修改

2022-03-21 05:46:06

本文主要介绍如何修改Android系统下载管理，以支持更多的功能及部分bug修改和如何编译生效。目前内容包括暂停下载、继续下载、通知设置NotiExtra和NotiClass、wifi切换到3g自动暂停、Bug修改。

更多下载相关开源项目可见 Android 下载。

PS: 很多童鞋不是自己做rom，所以就算修改了系统源码编译出来的包在其他系统上也不通用
这里推荐DownloadProvider@Github(并不是我的开源项目，我的项目为TrineaAndroidCommon@Github，包含图片缓存，下拉刷新，静默安装等，欢迎关注)，系统下载管理的独立版，可整合进自己的应用，感谢@DONG童鞋提供地址。

下面需要修改的DownloadManager.java所在目录为frameworks/base/core/java/android/app
DownloadInfo.java, DownloadProvider.java,DownloadThread.java文件所在目录为packages/providers/DownloadProvider/src/com/android/providers/downloads

1、暂停、继续下载功能
(1) DownloadProvider类修改

Java

1	public int update(final Uri uri, final ContentValues values, final String where, final String[] whereArgs)

函数，修改后代码如下(只增加了一行有效代码)：

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if (Binder.getCallingPid() != Process.myPid()) {
 filteredValues = new ContentValues();
 copyString(Downloads.Impl.COLUMN_APP_DATA, values, filteredValues);
 copyInteger(Downloads.Impl.COLUMN_VISIBILITY, values, filteredValues);
 Integer i = values.getAsInteger(Downloads.Impl.COLUMN_CONTROL);
 if (i != null) {
 filteredValues.put(Downloads.Impl.COLUMN_CONTROL, i);
 startService = true;
 }
 // trinea BEGIN, added by trinea@trinea.cn 2013/03/01
 copyInteger(Downloads.Impl.COLUMN_STATUS, values, filteredValues);
 // trinea END
 copyInteger(Downloads.Impl.COLUMN_CONTROL, values, filteredValues);
 copyString(Downloads.Impl.COLUMN_TITLE, values, filteredValues);
 copyString(Downloads.Impl.COLUMN_MEDIAPROVIDER_URI, values, filteredValues);
 copyString(Downloads.Impl.COLUMN_DESCRIPTION, values, filteredValues);
 copyInteger(Downloads.Impl.COLUMN_DELETED, values, filteredValues);
} else {

其中以// trinea BEGIN开头，// trinea END结尾为修改部分，下面代码示例同样如此。因为DownloadProvider安全策略对非该进程id的修改会过滤掉COLUMN_STATUS状态，所以我们需要添加该行。

(2) DownloadThread类修改

Java

1	private void setupDestinationFile(State state, InnerState innerState)

函数中这个注释掉一个else if，如下：

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// trinea BEGIN, noted by trinea@trinea.cn 2013/03/01
//} else if (mInfo.mETag == null && !mInfo.mNoIntegrity) {
// // This should've been caught upon failure
// if (Constants.LOGVV) {
// Log.d(TAG, "setupDestinationFile() unable to resume download, deleting "
// + state.mFilename);
// }
// f.delete();
// throw new StopRequestException(Downloads.Impl.STATUS_CANNOT_RESUME,
// "Trying to resume a download that can't be resumed");
// trinea END

上面一段代码表示一个验证过程，可以去掉。

mETag为数据库中的etag字段值，代码中没有解释，感觉是一个验证值，类似hashcode。
mNoIntegrity为数据中no_integrity字段值，表示启动下载的应用程序能否验证下载的文件的完整性。不过坑爹的是对于etag和no_integrity都没有提供设置的接口

(3) DownloadManager类中添加对外接口

DownloadManager中添加暂停、继续接口

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/**
 * pause download, added by trinea@trinea.cn 2013/03/01
 * 
 * @param ids the IDs of the downloads to be paused
 * @return the number of downloads actually paused
 */
public int pauseDownload(long... ids) {
 if (ids == null || ids.length == 0) {
 // called with nothing to remove!
 throw new IllegalArgumentException("input param 'ids' can't be null");
 }
 ContentValues values = new ContentValues();
 values.put(Downloads.Impl.COLUMN_CONTROL, Downloads.Impl.CONTROL_PAUSED);
 values.put(Downloads.Impl.COLUMN_STATUS, Downloads.Impl.STATUS_PAUSED_BY_APP);
 if (ids.length == 1) {
 return mResolver.update(ContentUris.withAppendedId(mBaseUri, ids[0]), values,
 null, null);
 } 
 return mResolver.update(mBaseUri, values, getWhereClauseForIds(ids),
 getWhereArgsForIds(ids));
}
/**
 * resume download, added by trinea@trinea.cn 2013/03/01
 * 
 * @param ids the IDs of the downloads to be resumed
 * @return the number of downloads actually resumed
 */
public int resumeDownload(long... ids) {
 if (ids == null || ids.length == 0) {
 // called with nothing to remove!
 throw new IllegalArgumentException("input param 'ids' can't be null");
 }
 ContentValues values = new ContentValues();
 values.put(Downloads.Impl.COLUMN_CONTROL, Downloads.Impl.CONTROL_RUN);
 values.put(Downloads.Impl.COLUMN_STATUS, Downloads.Impl.STATUS_RUNNING);
 if (ids.length == 1) {
 return mResolver.update(ContentUris.withAppendedId(mBaseUri, ids[0]), values,
 null, null);
 } 
 return mResolver.update(mBaseUri, values, getWhereClauseForIds(ids),
 getWhereArgsForIds(ids));
}

无论是暂停还是继续我们都是同时把Downloads.Impl.COLUMN_CONTROL和Downloads.Impl.COLUMN_STATUS字段进行修改，因为在DownloadInfo的private boolean isReadyToStart(long now)函数中,会对COLUMN_CONTROL字段进行判断，如果是用户手动暂停的话，是不会自动继续的，部分代码如下：

点击展开代码

之后我们直接调用DownloadManager的pauseDownload和resumeDownload接口即可

PS：也可以试试不做第二步的修改，而将第一步DownloadProvider的update函数修改变为

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// trinea BEGIN, added by trinea@trinea.cn 2013/03/01
copyInteger(Downloads.Impl.COLUMN_STATUS, values, filteredValues);
copyInteger(Downloads.Impl.COLUMN_NO_INTEGRITY, values, filteredValues);
// trinea END

第二步修改变为在public int resumeDownload(long… ids)加入

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values.put(Downloads.Impl.COLUMN_CONTROL, Downloads.Impl.CONTROL_RUN);
values.put(Downloads.Impl.COLUMN_STATUS, Downloads.Impl.STATUS_RUNNING);
values.put(Downloads.Impl.COLUMN_NO_INTEGRITY, true);

没有亲自试，不过按照逻辑应该也可以。

2、通知栏可以设置NotiExtra和NotiClass

(1) DownloadProvider类中修改private void checkInsertPermissions(ContentValues values)函数

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values.remove(Downloads.Impl.COLUMN_IS_VISIBLE_IN_DOWNLOADS_UI);
values.remove(Downloads.Impl.COLUMN_MEDIA_SCANNED);
// BEGIN, added by trinea@trinea.cn 2013/03/01
values.remove(Downloads.Impl.COLUMN_NOTIFICATION_CLASS);
values.remove(Downloads.Impl.COLUMN_NOTIFICATION_EXTRAS);
// trinea END

在DownloadProvider insert之前会调用checkInsertPermissions检查不能被插入的字段插入，这里我们需要允许这两个字段存在。

(2) DownloadManager.Request添加对外接口

DownloadManager.Request支持setNotiClass、setNotiExtras

在Request中添加接口以及允许字段修改。通过允许设置NotiExtra和NotiClass，我们可以给系统传递更丰富的参数，在通知栏点击相应或是DownloadUi中通过broadcast将这些参数传递出来方便应用调用。

3、wifi切换到3g自动暂停
(1) 修改DownloadInfo.java

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private int checkIsNetworkTypeAllowed(int networkType) {
 if (mIsPublicApi) {
 final int flag = translateNetworkTypeToApiFlag(networkType);
 final boolean allowAllNetworkTypes = mAllowedNetworkTypes == ~0;
 if (!allowAllNetworkTypes && (flag & mAllowedNetworkTypes) == 0) {
 return NETWORK_TYPE_DISALLOWED_BY_REQUESTOR;
 }
 // trinea BEGIN
 if (mStatus == Downloads.Impl.STATUS_WAITING_FOR_NETWORK 
 && flag != DownloadManager.Request.NETWORK_WIFI) {
 return NETWORK_TYPE_DISALLOWED_BY_REQUESTOR;
 }
 // trinea END
 }
 return checkSizeAllowedForNetwork(networkType);
}

表示等待网络时始终只等待wifi

(2) 修改DownloadReceiver.java

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} else if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
 NetworkInfo info = (NetworkInfo)
 intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
 if (info != null && info.isConnected()) {
 startService(context);
 }
} else if (action.equals(Constants.ACTION_RETRY)) {

修改为：

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} else if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
 NetworkInfo info = (NetworkInfo)
 intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
 // trinea BEGIN
 /** 
	 * modified by trinea@trinea.cn @2013/04/01, resume download only when network type is wifi
	 */
 if (info != null && info.isConnected() && info.getType() == ConnectivityManager.TYPE_WIFI) {
 // trinea END
 startService(context);
 }
} else if (action.equals(Constants.ACTION_RETRY)) {

表示只有连接wifi时才唤醒service去检查是否下载

(3) 修改DownloadThread.java

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/**
 * Check if the download has been paused or canceled, stopping the request appropriately if it
 * has been.
 */
private void checkPausedOrCanceled(State state) throws StopRequestException {
 synchronized (mInfo) {
 if (mInfo.mControl == Downloads.Impl.CONTROL_PAUSED) {
 Xlog.i(Constants.DL_ENHANCE, "DownloadThread: checkPausedOrCanceled: user pause download");
 throw new StopRequestException(
 Downloads.Impl.STATUS_PAUSED_BY_APP, "download paused by owner");
 }
 if (mInfo.mStatus == Downloads.Impl.STATUS_CANCELED) {
 throw new StopRequestException(Downloads.Impl.STATUS_CANCELED, "download canceled");
 }
 }
 // if policy has been changed, trigger connectivity check
 if (mPolicyDirty) {
 // trinea BEGIN
 /** 
		 * add by trinea@trinea.cn @2013/04/01, when switched from wifi to 3g, pause all download
		 */
 NetworkInfo info = mSystemFacade.getActiveNetworkInfo(mInfo.mUid);
 if (info != null && !info.isConnected()) {
 mInfo.mStatus = Downloads.Impl.STATUS_WAITING_FOR_NETWORK;
 }
 // trinea END
 checkConnectivity();
 }
}

表示如果网络变化并且表示网络断开时，下载状态变为等待网络。

4、Bug修改
(1) 当存储空间不足时，利用DownloadManager下载，只显示通知栏提示，在下载管理UI中不显示
DownloadManager的Cursor runQuery(ContentResolver resolver, String[] projection, Uri baseUri)函数修改如下：

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if ((mStatusFlags & STATUS_RUNNING) != 0) {
 parts.add(statusClause("=", Downloads.Impl.STATUS_RUNNING));
 // trinea BEGIN
 parts.add(statusClause("=", Downloads.Impl.STATUS_INSUFFICIENT_SPACE_ERROR));
 // trinea END
}

DownloadManager的CursorTranslator类的private int translateStatus(int status) 函数修改如下：

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// trinea BEGIN
case Downloads.Impl.STATUS_INSUFFICIENT_SPACE_ERROR:
// trinea END
case Downloads.Impl.STATUS_RUNNING:
 return STATUS_RUNNING;

5、编译安装

修改后是需要重新编译的，需同时编译framweork和DownloadProvider。

framework编译命令为：./makeMtk model mm frameworks/base/core/
编译后apk所在路径为out\target\product\model\system\framework\secondary_framework.jar，之后push到system/framework重启即可。编译命令中model为机型，非mtk平台命令有所不同

DownloadProvider编译命令为./makeMtk model mm packages/providers/DownloadProvider/
编译后apk所在路径为out\target\product\model\system\app\DownloadProvider.apk，之后push到system/app即可(可能需要先删除/system/app/目录下的DownloadProvider.odex)

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