为什么加载完成后要多次执行操作,为什么要对所有事件进行排队?

在加载时,当我们单击返回按钮或表格的任何单元格时,加载完成后会多次调用该操作。这里是我在开始加载和停止加载时所做的代码片段。

+(void)showLoader_OnView{
      APP_DELEGATE.window.userInteractionEnabled = NO;
     [MBProgressHUD showHUDAddedTo:APP_DELEGATE.window animated:YES];
}

要停止加载:-

+(void)hideLoader {
    APP_DELEGATE.window.userInteractionEnabled =YES;
    [MBProgressHUD hideAllHUDsForView:APP_DELEGATE.window animated:YES];
}

请帮帮我。

使现代化

实际上,我正在从服务器获取数据。每当用户进入下一个窗口时,在viewWillAppear函数中,我调用一个函数,该函数将调用api来获取数据。

-(void)performAutoSync
{
    @try
    {
        if(self.shouldPerformAutoSync)//Necessary conditions to check the auto sync
        {
            [AppConstants showLoader_OnView];  //here i call the loader.
            self.shouldPerformAutoSync  = NO;
            if(!self.isSyncing)
            {
                if(!syncBl)
                {
                    syncBl = [[SyncBL alloc] init];
                    syncBl.delegate = self;
                }

                if(!syncDl)
                    syncDl = [[SyncDL alloc] init];

                //            [self saveModifiedDataForCurrentViewController];


                [self delayToAutoSync];


                NSMutableDictionary *dictMainData = [NSMutableDictionary new];
                [dictMainData setObject:[syncDl fetchCompleteDataAndPrepareDictionary:YES] forKey:@"data"];//@"MainData"];
                [syncBl performAutoSync:dictMainData];
            }
        }
    }
    @catch (NSException *exception) {
        BILog(@"%@",exception);
    }

}