ios - 网络请求数据重复的可能

Question

看代码：

#viewDidLoad

    [self getActivityListFromNetwork];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(refreshActivityListFromNetwork)
                                                 name:@"backRefresh"
                                               object:nil];

#refreshActivityListFromNetwork
- (void)refreshActivityListFromNetwork{
    [self.dataArray removeAllObjects];
    [self getActivityListFromNetwork];
    [self.mainTableView headerEndRefreshing];
}                                             
                                       
                                               

问题是：如果注销后重新登录的话会有一定概率出现重复数据。
分析原因是点击登录后，页面加载执行了getActivityListFromNetwork这个方法。这时候去请求数据。在没有返回数据前执行了refreshActivityListFromNetwork又一次去请求了数据。导致两次请求获得的数据都加载出来了。。。

Answer 1

Execute removeAllObjects and reloadData after each data request is successful. In addition, it is best to provide a corresponding caching mechanism for your network request method. When there is no new data, there is no need to update the data source.

Answer 2

Ask and answer your own questions. . . .

Answer 3

Why is it not executed after the network request comes back to obtain the data[self.dataArray removeAllObjects];?

Answer 4

I agree with you upstairs, the data source removeAllObjects should be placed in the successful network request

Answer 5

Um, why are you writing it in such a disgusting way? Agent, block deserves your own