如何在用户在ios中查看视图之前加载数据？

Question

In my case i have two views in tab bar controller (categories and Home), one with collection view and one with table view. In the table view, It starts to load data when only user taps(Home) on its tab bar item.I want to load data , when app launch. I am using AFNetworking , and I have called to my data loading method in viewDidLoad. same thing happen with collection view.please help me with this.hope your help thank you. I have attached part of my code, which I used to load data to table view.

- (void)viewDidLoad {
    [super viewDidLoad];

    [self.view addSubview:self.homeTableView];
//    [self homeviewData];

    SWRevealViewController *revealController = self.revealViewController;
    if (revealController) {
        [self.sidebarButton setTarget:self.revealViewController];
        [self.sidebarButton setAction:@selector(revealToggle:)];
        [self.view addGestureRecognizer:self.revealViewController.panGestureRecognizer];
    }
    // Do any additional setup after loading the view.
}

- (void)viewWillAppear:(BOOL)animated
{
    [self homeTableView];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)homeviewData
{
    homepost = nil;
    NSString *mogohomeWebserviceUrl = [NSString stringWithFormat:@"some url"];
    AFHTTPRequestOperationManager *homeManager = [AFHTTPRequestOperationManager manager];
    [homeManager GET:mogohomeWebserviceUrl parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {

        homeposts = (NSDictionary *)responseObject;
        homepost = [NSMutableArray array];
        NSArray *results = [homeposts objectForKey:@"posts"];
        for (NSDictionary *all in results)
        {
            Home *sweetHome = [Home new];
            sweetHome.homeImage = [NSString stringWithFormat:@"%@", [all objectForKey:@"thumbnail"]];
            sweetHome.homeTitle = [NSString stringWithFormat:@"%@", [all objectForKey:@"title"]];
            sweetHome.homewebUrl = [NSString stringWithFormat:@"%@", [all objectForKey:@"url"]];
            sweetHome.modifiedTime = [NSString stringWithFormat:@"%@", [all objectForKey:@"modified"]];

            [homepost addObject:sweetHome];
            [self.homeTableView reloadData];

        }

    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {

    }];

}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [homepost count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    HomeTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"homereuseIdentifier"];
    Home *mogoHome = [homepost objectAtIndex:indexPath.row];

    NSString *homeimageurlname = [NSString stringWithFormat:@"%@", mogoHome.homeImage];
    NSURL *homeimageurl = [NSURL URLWithString:homeimageurlname];

    cell.hometitleLabel.text = mogoHome.homeTitle;
    [cell.homeimageView setImageWithURL:homeimageurl placeholderImage:nil];
    cell.timeLabel.text = [[mogoHome.modifiedTime componentsSeparatedByString:@" "] objectAtIndex:1];
    return cell;
}

Answer 1

You got to understand that the data will only be loaded and displayed after the API request to fetch the data is completed...

This implies you should either be ready with data before the screen appears. This is possible only if the data is independent of user action or Master Data, and you can fetch it right at App Launch. If user action is responsible for the fetched data, you have no option but to wait, and show an Activity Indicator. If you decide to do this, you will find a relevant answers how to do that..

All the best...