android 应用程序使用统计

Class<?> cServiceManager = Class                  .forName("android.os.ServiceManager");          Method mGetService = cServiceManager.getMethod("getService",                  java.lang.String.class);          Object oRemoteService = mGetService.invoke(null, "usagestats");            // IUsageStats oIUsageStats =          // IUsageStats.Stub.asInterface(oRemoteService)          Class<?> cStub = Class                  .forName("com.android.internal.app.IUsageStats$Stub");          Method mUsageStatsService = cStub.getMethod("asInterface",                  android.os.IBinder.class);          Object oIUsageStats = mUsageStatsService.invoke(null,                  oRemoteService);            // PkgUsageStats[] oPkgUsageStatsArray =          // mUsageStatsService.getAllPkgUsageStats();          Class<?> cIUsageStatus = Class                  .forName("com.android.internal.app.IUsageStats");          Method mGetAllPkgUsageStats = cIUsageStatus.getMethod(                  "getAllPkgUsageStats", (Class[]) null);          Object[] oPkgUsageStatsArray = (Object[]) mGetAllPkgUsageStats                  .invoke(oIUsageStats, (Object[]) null);          System.out.println(oPkgUsageStatsArray);            Class<?> cPkgUsageStats = Class                  .forName("com.android.internal.os.PkgUsageStats");            for (Object pkgUsageStats : oPkgUsageStatsArray) {              // get pkgUsageStats.packageName, pkgUsageStats.launchCount,              // pkgUsageStats.usageTime              String packageName = (String) cPkgUsageStats.getDeclaredField(                      "packageName").get(pkgUsageStats);              int launchCount = cPkgUsageStats                      .getDeclaredField("launchCount").getInt(pkgUsageStats);              long usageTime = cPkgUsageStats.getDeclaredField("usageTime")                      .getLong(pkgUsageStats);              System.out.println(packageName + ":" + launchCount + ":"                      + usageTime);  

这个系统权限不知道怎么添加

<uses-permission android:name="android.permission.PACKAGE_USAGE_STATS"/>  

该方法实验没有通过，说是因为没有上面的这个权限，我把该放在manifest中没有效果，后来网上查了一下说是系统权限，自己不会弄就没有继续测试了