关键字： 应用统计 Android源码 应用使用时长 应用使用次数
上篇文章讲到关于Android系统应用数据统计的结果及其相关的数据结构，接下来主要从源码方面分析系统是如何记录相关数据的。
首先，我们可以找到这样一个Service。
/**
* A service that collects, aggregates, and persists application usage data.
* This data can be queried by apps that have been granted permission by AppOps.
*/
public class UsageStatsService extends SystemService implements
UserUsageStatsService.StatsUpdatedListener {
@Override
public void onStart() {
mAppOps = (AppOpsManager) getContext().getSystemService(Context.APP_OPS_SERVICE);
mUserManager = (UserManager) getContext().getSystemService(Context.USER_SERVICE);
mHandler = new H(BackgroundThread.get().getLooper());
//正如第一篇文章所阐述的那样，建立相关的文件目录
File systemDataDir = new File(Environment.getDataDirectory(), "system");
mUsageStatsDir = new File(systemDataDir, "usagestats");
mUsageStatsDir.mkdirs();
if (!mUsageStatsDir.exists()) {
throw new IllegalStateException("Usage stats directory does not exist: "
+ mUsageStatsDir.getAbsolutePath());
}
getContext().registerReceiver(new UserRemovedReceiver(),
new IntentFilter(Intent.ACTION_USER_REMOVED));
synchronized (mLock) {
cleanUpRemovedUsersLocked();
}
//这里的时间，也可以稍微注意下，因为每次记录都会就爱那个相关时间戳写入文件中
mRealTimeSnapshot = SystemClock.elapsedRealtime();
mSystemTimeSnapshot = System.currentTimeMillis();
//以下两行最为关键，注册了两个Service
publishLocalService(UsageStatsManagerInternal.class, new LocalService());
publishBinderService(Context.USAGE_STATS_SERVICE, new BinderService());
}
将UsageStatsService的注释翻译过来，可知，该Service用于收集，统计，保存相关的应用使用情况的数据。在第三方应用权限允许的情况下，可以为该应用提供这些数据。在检查了相关文件目录，完成对应的准备工作之后，UsageStatsService注册了两个Service，分别为 LocalService 和 BinderService。这两个Service是UsageStatsService的两个内部类。具体如下：
LocalService
/**
* This local service implementation is primarily used by ActivityManagerService.
* ActivityManagerService will call these methods holding the 'am' lock, which means we
* shouldn't be doing any IO work or other long running tasks in these methods.
*/
private class LocalService extends UsageStatsManagerInternal {
@Override
public void reportEvent(ComponentName component, int userId, int eventType) {
if (component == null) {
Slog.w(TAG, "Event reported without a component name");
return;
}
UsageEvents.Event event = new UsageEvents.Event();
event.mPackage = component.getPackageName();
event.mClass = component.getClassName();
// This will later be converted to system time.
event.mTimeStamp = SystemClock.elapsedRealtime();
event.mEventType = eventType;
mHandler.obtainMessage(MSG_REPORT_EVENT, userId, 0, event).sendToTarget();
}
@Override
public void reportConfigurationChange(Configuration config, int userId) {
if (config == null) {
Slog.w(TAG, "Configuration event reported with a null config");
return;
}
UsageEvents.Event event = new UsageEvents.Event();
event.mPackage = "android";
// This will later be converted to system time.
event.mTimeStamp = SystemClock.elapsedRealtime();
event.mEventType = UsageEvents.Event.CONFIGURATION_CHANGE;
event.mConfiguration = new Configuration(config);
mHandler.obtainMessage(MSG_REPORT_EVENT, userId, 0, event).sendToTarget();
}
@Override
public void prepareShutdown() {
// This method *WILL* do IO work, but we must block until it is finished or else
// we might not shutdown cleanly. This is ok to do with the 'am' lock held, because
// we are shutting down.
//其实此处就是调用下文中提到的flushToDiskLocked()，这一函数
shutdown();
}
}
正如注释的那样，此Service由ActivityManagerService调用的，不进行I/O等耗时操作的服务，记录每一次event和config数据。从代码中可以看出来，reportConfigurationChange（）和reportEvent（）都是new一个Event，然后交由mHandler处理。
mHandler
class H extends Handler {
public H(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_REPORT_EVENT:
reportEvent((UsageEvents.Event) msg.obj, msg.arg1);
break;
case MSG_FLUSH_TO_DISK:
flushToDisk();
break;
case MSG_REMOVE_USER:
removeUser(msg.arg1);
break;
default:
super.handleMessage(msg);
break;
}
}
}
以上是mHandler的源码，针对上面三条message，我们在UsageStatsService中可以找到其最终调用的函数如下
void reportEvent(UsageEvents.Event event, int userId) {
synchronized (mLock) {
final long timeNow = checkAndGetTimeLocked();
convertToSystemTimeLocked(event);
final UserUsageStatsService service =
getUserDataAndInitializeIfNeededLocked(userId, timeNow);
service.reportEvent(event);
}
}
private void flushToDiskLocked() {
final int userCount = mUserState.size();
for (int i = 0; i < userCount; i++) {
UserUsageStatsService service = mUserState.valueAt(i);
service.persistActiveStats();
}
mHandler.removeMessages(MSG_FLUSH_TO_DISK);
}
//此函数就不过多注释了，其目的就是在系统文件目录中，删除部分系统用户，及其目录下的一系列的Usage数据
void removeUser(int userId) {
synchronized (mLock) {
Slog.i(TAG, "Removing user " + userId + " and all data.");
mUserState.remove(userId);
cleanUpRemovedUsersLocked();
}
}
从上面可以得出，上报event，并且写入磁盘，最终都会调用UserUsageStatsService 这个类（此类会在下篇文章中讲到）。
BinderService
private class BinderService extends IUsageStatsManager.Stub {
private boolean hasPermission(String callingPackage) {
final int callingUid = Binder.getCallingUid();
if (callingUid == Process.SYSTEM_UID) {
return true;
}
final int mode = mAppOps.checkOp(AppOpsManager.OP_GET_USAGE_STATS,
callingUid, callingPackage);
if (mode == AppOpsManager.MODE_DEFAULT) {
// The default behavior here is to check if PackageManager has given the app
// permission.
return getContext().checkCallingPermission(Manifest.permission.PACKAGE_USAGE_STATS)
== PackageManager.PERMISSION_GRANTED;
}
return mode == AppOpsManager.MODE_ALLOWED;
}
@Override
public ParceledListSlice<UsageStats> queryUsageStats(int bucketType, long beginTime,
long endTime, String callingPackage) {
if (!hasPermission(callingPackage)) {
return null;
}
final int userId = UserHandle.getCallingUserId();
final long token = Binder.clearCallingIdentity();
try {
final List<UsageStats> results = UsageStatsService.this.queryUsageStats(
userId, bucketType, beginTime, endTime);
if (results != null) {
return new ParceledListSlice<>(results);
}
} finally {
Binder.restoreCallingIdentity(token);
}
return null;
}
@Override
public ParceledListSlice<ConfigurationStats> queryConfigurationStats(int bucketType,
long beginTime, long endTime, String callingPackage) throws RemoteException {
if (!hasPermission(callingPackage)) {
return null;
}
final int userId = UserHandle.getCallingUserId();
final long token = Binder.clearCallingIdentity();
try {
final List<ConfigurationStats> results =
UsageStatsService.this.queryConfigurationStats(userId, bucketType,
beginTime, endTime);
if (results != null) {
return new ParceledListSlice<>(results);
}
} finally {
Binder.restoreCallingIdentity(token);
}
return null;
}
@Override
public UsageEvents queryEvents(long beginTime, long endTime, String callingPackage) {
if (!hasPermission(callingPackage)) {
return null;
}
final int userId = UserHandle.getCallingUserId();
final long token = Binder.clearCallingIdentity();
try {
return UsageStatsService.this.queryEvents(userId, beginTime, endTime);
} finally {
Binder.restoreCallingIdentity(token);
}
}
@Override
protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
if (getContext().checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
!= PackageManager.PERMISSION_GRANTED) {
pw.println("Permission Denial: can't dump UsageStats from pid="
+ Binder.getCallingPid() + ", uid=" + Binder.getCallingUid()
+ " without permission " + android.Manifest.permission.DUMP);
return;
}
UsageStatsService.this.dump(args, pw);
}
}
/**
* 被上述BinderService调用
* Called by the Binder stub.
*/
List<UsageStats> queryUsageStats(int userId, int bucketType, long beginTime, long endTime) {
synchronized (mLock) {
final long timeNow = checkAndGetTimeLocked();
if (!validRange(timeNow, beginTime, endTime)) {
return null;
}
final UserUsageStatsService service =
getUserDataAndInitializeIfNeededLocked(userId, timeNow);
return service.queryUsageStats(bucketType, beginTime, endTime);
}
}
/**
* 被上述BinderService调用
* Called by the Binder stub.
*/
List<ConfigurationStats> queryConfigurationStats(int userId, int bucketType, long beginTime,
long endTime) {
synchronized (mLock) {
final long timeNow = checkAndGetTimeLocked();
if (!validRange(timeNow, beginTime, endTime)) {
return null;
}
final UserUsageStatsService service =
getUserDataAndInitializeIfNeededLocked(userId, timeNow);
return service.queryConfigurationStats(bucketType, beginTime, endTime);
}
}
/**
* 被上述BinderService调用
* Called by the Binder stub.
*/
UsageEvents queryEvents(int userId, long beginTime, long endTime) {
synchronized (mLock) {
final long timeNow = checkAndGetTimeLocked();
if (!validRange(timeNow, beginTime, endTime)) {
return null;
}
final UserUsageStatsService service =
getUserDataAndInitializeIfNeededLocked(userId, timeNow);
return service.queryEvents(beginTime, endTime);
}
}
BinderService，可以看出主要用于查询UsageStats数据，包括UsageStats，ConfigurationStats，UsageEvents 。显然，查询借口和LocalService一样，调用UserUsageStatsService接口，此类将在下一篇文章中继续解析。
结语：
本文主要介绍了系统关于查询获取系统统计信息的api的部分相关源码，主要是利用Service，进行数据的查询和记录。接下来的文章将主要介绍其调用的UserUsageStatsService 的具体实现及其逻辑。
转载请注明出处。
github：UseTimeStatistic
参考文献：
相关源码链接
Android5.1应用统计源码分析
Android5.1应用打开次数获取
