private async Task QueryActivity()
        {
            UserContentProvider user = new UserContentProvider();
            List<ActivityResult> result = await user.QueryFriendActivities(0, GlobalValue.CurrentUserContext.UserId, GlobalValue.CurrentUserContext.MobileToken);


            ActivityResult = new ObservableCollection<ActivityItem>();

            foreach (var item in result)
            {
                ActivityResult.Add(ConvertToActivityItem(item));
            }

            //循环添加数据到20条
            while(ActivityResult.Count <20)
            {
                List<ActivityResult> loop = await user.QueryFriendActivities(ActivityResult[ActivityResult.Count - 1].ActivityId - 1, 
                    GlobalValue.CurrentUserContext.UserId, GlobalValue.CurrentUserContext.MobileToken);

                if (loop.Count == 0) break;

                foreach (var item in loop)
                {
                    ActivityResult.Add(ConvertToActivityItem(item));
                }
            }
        }
 public async Task QueryFriendActivitiesTest()
 {
     UserContentProvider mine = new UserContentProvider();
     LoginResult result = await mine.Login(Config.username, Config.password);
     List<ActivityResult> nr = await mine.QueryFriendActivities(0, result.Id.ToString(), result.MobileToken);
     Assert.IsNotNull(nr);
 }
        private async Task MoreActivity()
        {
            UserContentProvider user = new UserContentProvider();
            List<ActivityResult> result = await user.QueryFriendActivities(
                ActivityResult[ActivityResult.Count - 1].ActivityId - 1, GlobalValue.CurrentUserContext.UserId, GlobalValue.CurrentUserContext.MobileToken);

            foreach (var item in result)
            {
                ActivityResult.Add(ConvertToActivityItem(item));
            }
        }