事件传递的顺序：Activity -> ViewGroup -> View

       public class SCApplication extends Application { private static final String TAG = "SCApplication"; private static SCApplication mApplication; private static SecondLevelCache secondLevelCacheKit; public static SecondLevelCache getSecondLevelCacheKit() { return secondLevelCacheKit; } public static synchronized SCApplication getApplicationInstance() { if (mApplication == null) { mApplication = new SCApplication(); } return mApplication; } @Override public void onCreate() { super.onCreate(); mApplication = this; secondLevelCacheKit = SecondLevelCache.getInstance(this);