關(guān)鍵字： 應(yīng)用統(tǒng)計 Android源碼 應(yīng)用使用時長 應(yīng)用使用次數(shù)

上篇文章講到關(guān)于Android系統(tǒng)應(yīng)用數(shù)據(jù)統(tǒng)計的結(jié)果及其相關(guān)的數(shù)據(jù)結(jié)構(gòu)，接下來主要從源碼方面分析系統(tǒng)是如何記錄相關(guān)數(shù)據(jù)的。

首先，我們可以找到這樣一個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());

        //正如第一篇文章所闡述的那樣，建立相關(guān)的文件目錄
        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();
        }
        //這里的時間，也可以稍微注意下，因為每次記錄都會就愛那個相關(guān)時間戳寫入文件中
        mRealTimeSnapshot = SystemClock.elapsedRealtime();
        mSystemTimeSnapshot = System.currentTimeMillis();

        //以下兩行最為關(guān)鍵，注冊了兩個Service
        publishLocalService(UsageStatsManagerInternal.class, new LocalService());
        publishBinderService(Context.USAGE_STATS_SERVICE, new BinderService());
   }

將UsageStatsService的注釋翻譯過來，可知，該Service用于收集，統(tǒng)計，保存相關(guān)的應(yīng)用使用情況的數(shù)據(jù)。在第三方應(yīng)用權(quán)限允許的情況下，可以為該應(yīng)用提供這些數(shù)據(jù)。在檢查了相關(guān)文件目錄，完成對應(yīng)的準(zhǔn)備工作之后，UsageStatsService注冊了兩個Service，分別為 LocalService 和 BinderService。這兩個Service是UsageStatsService的兩個內(nèi)部類。具體如下：

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.
            //其實此處就是調(diào)用下文中提到的flushToDiskLocked()，這一函數(shù)
            shutdown();
        }
    }

正如注釋的那樣，此Service由ActivityManagerService調(diào)用的，不進行I/O等耗時操作的服務(wù)，記錄每一次event和config數(shù)據(jù)。從代碼中可以看出來，reportConfigurationChange（）和reportEvent（）都是new一個Event，然后交由mHandler處理。

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的源碼，針對上面三條message，我們在UsageStatsService中可以找到其最終調(diào)用的函數(shù)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);
    }

//此函數(shù)就不過多注釋了，其目的就是在系統(tǒng)文件目錄中，刪除部分系統(tǒng)用戶，及其目錄下的一系列的Usage數(shù)據(jù)
void removeUser(int userId) {
        synchronized (mLock) {
            Slog.i(TAG, "Removing user " + userId + " and all data.");
            mUserState.remove(userId);
            cleanUpRemovedUsersLocked();
        }
    }

從上面可以得出，上報event，并且寫入磁盤，最終都會調(diào)用UserUsageStatsService 這個類（此類會在下篇文章中講到）。

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調(diào)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調(diào)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調(diào)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詢UsageStats數(shù)據(jù)，包括UsageStats，ConfigurationStats，UsageEvents 。顯然，查詢借口和LocalService一樣，調(diào)用UserUsageStatsService接口，此類將在下一篇文章中繼續(xù)解析。

結(jié)語：

本文主要介紹了系統(tǒng)關(guān)于查詢獲取系統(tǒng)統(tǒng)計信息的api的部分相關(guān)源碼，主要是利用Service，進行數(shù)據(jù)的查詢和記錄。接下來的文章將主要介紹其調(diào)用的UserUsageStatsService 的具體實現(xiàn)及其邏輯。

轉(zhuǎn)載請注明出處。

github：UseTimeStatistic
參考文獻：
相關(guān)源碼鏈接
Android5.1應(yīng)用統(tǒng)計源碼分析
Android5.1應(yīng)用打開次數(shù)獲取

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