Ios dispatch\u async UITableView重载数据

我有一个问题，当启动viewDidLoad方法时，数据会在UITableView中正确加载和显示，但当我必须通过clickPopular方法重新加载数据时，TableView不会更新

有什么办法可以做到这一点吗

视图加载方法

-(void)viewDidLoad
{
Name = [[NSMutableArray alloc] init];
slug = [[NSMutableArray alloc] init];
Immagine = [[NSMutableArray alloc] init];
visite = [[NSMutableArray alloc] init];
categorie = [[NSMutableArray alloc] init];

[[NSUserDefaults standardUserDefaults] setObject:@"recent" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(IBAction)clickPopular:(id)sender{
    [tableView reloadData];

    [[NSUserDefaults standardUserDefaults] setObject:@"popular" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];
    [self StartCaricamento];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(void)LoadJson
{

    NSString *filtro = [[NSUserDefaults standardUserDefaults] objectForKey:@"settings_home_filter"];

    NSString *stringachiamata = [NSString stringWithFormat:@"https://www.mywebsite.com/videos/latest?count=100&ln=en&result_type=%@", filtro];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:stringachiamata]];
    [request setHTTPMethod:@"GET"];
    [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

    NSError *err;
    NSURLResponse *response;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

    if(err != nil)
    {
        NSLog(@"Error Parsing JSON: %@", err);
    }
    else
    {
        NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];
        array = [jsonArray objectForKey:@"videos"];

        NSLog(@"%d", [array count]);

        for (int i = 0; i < [array count]; i++)
        {            
            [Name addObject:[[array objectAtIndex:i] objectForKey:@"name"]];
            [slug addObject:[[array objectAtIndex:i] objectForKey:@"slug_video"]];
            [Immagine addObject:[[array objectAtIndex:i] objectForKey:@"thumbnail_video_original"]];
            [visite addObject:[[array objectAtIndex:i] objectForKey:@"views_video"]];
            [categorie addObject:[[array objectAtIndex:i] objectForKey:@"category_name_video"]];
        }

    }
}

流行方法

-(void)viewDidLoad
{
Name = [[NSMutableArray alloc] init];
slug = [[NSMutableArray alloc] init];
Immagine = [[NSMutableArray alloc] init];
visite = [[NSMutableArray alloc] init];
categorie = [[NSMutableArray alloc] init];

[[NSUserDefaults standardUserDefaults] setObject:@"recent" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(IBAction)clickPopular:(id)sender{
    [tableView reloadData];

    [[NSUserDefaults standardUserDefaults] setObject:@"popular" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];
    [self StartCaricamento];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(void)LoadJson
{

    NSString *filtro = [[NSUserDefaults standardUserDefaults] objectForKey:@"settings_home_filter"];

    NSString *stringachiamata = [NSString stringWithFormat:@"https://www.mywebsite.com/videos/latest?count=100&ln=en&result_type=%@", filtro];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:stringachiamata]];
    [request setHTTPMethod:@"GET"];
    [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

    NSError *err;
    NSURLResponse *response;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

    if(err != nil)
    {
        NSLog(@"Error Parsing JSON: %@", err);
    }
    else
    {
        NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];
        array = [jsonArray objectForKey:@"videos"];

        NSLog(@"%d", [array count]);

        for (int i = 0; i < [array count]; i++)
        {            
            [Name addObject:[[array objectAtIndex:i] objectForKey:@"name"]];
            [slug addObject:[[array objectAtIndex:i] objectForKey:@"slug_video"]];
            [Immagine addObject:[[array objectAtIndex:i] objectForKey:@"thumbnail_video_original"]];
            [visite addObject:[[array objectAtIndex:i] objectForKey:@"views_video"]];
            [categorie addObject:[[array objectAtIndex:i] objectForKey:@"category_name_video"]];
        }

    }
}

加载JSON方法

-(void)viewDidLoad
{
Name = [[NSMutableArray alloc] init];
slug = [[NSMutableArray alloc] init];
Immagine = [[NSMutableArray alloc] init];
visite = [[NSMutableArray alloc] init];
categorie = [[NSMutableArray alloc] init];

[[NSUserDefaults standardUserDefaults] setObject:@"recent" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(IBAction)clickPopular:(id)sender{
    [tableView reloadData];

    [[NSUserDefaults standardUserDefaults] setObject:@"popular" forKey:@"settings_home_filter"];
    [[NSUserDefaults standardUserDefaults] synchronize];
    [self StartCaricamento];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self LoadJson];

        dispatch_async(dispatch_get_main_queue(), ^{
            [tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationNone];

            [tableView reloadData];
            [self StopCaricamento];
        });
    });
}

-(void)LoadJson
{

    NSString *filtro = [[NSUserDefaults standardUserDefaults] objectForKey:@"settings_home_filter"];

    NSString *stringachiamata = [NSString stringWithFormat:@"https://www.mywebsite.com/videos/latest?count=100&ln=en&result_type=%@", filtro];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:stringachiamata]];
    [request setHTTPMethod:@"GET"];
    [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

    NSError *err;
    NSURLResponse *response;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

    if(err != nil)
    {
        NSLog(@"Error Parsing JSON: %@", err);
    }
    else
    {
        NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];
        array = [jsonArray objectForKey:@"videos"];

        NSLog(@"%d", [array count]);

        for (int i = 0; i < [array count]; i++)
        {            
            [Name addObject:[[array objectAtIndex:i] objectForKey:@"name"]];
            [slug addObject:[[array objectAtIndex:i] objectForKey:@"slug_video"]];
            [Immagine addObject:[[array objectAtIndex:i] objectForKey:@"thumbnail_video_original"]];
            [visite addObject:[[array objectAtIndex:i] objectForKey:@"views_video"]];
            [categorie addObject:[[array objectAtIndex:i] objectForKey:@"category_name_video"]];
        }

    }
}

---

重新加载时，您永远不会清除阵列

这意味着在分派\u async之前重新加载时，旧条目仍会保留

[Name removeAllObjects];
[slug removeAllObjects];
[Immagine removeAllObjects];
[visit eremoveAllObjects];
[categorie removeAllObjects];

---

实际上。。作为-（iAction）clickPopular:（id）sender的第一行执行此操作{

在

viewdiload

中不要调用

startcaricanto

。最好不要在

viewdiload

中初始化

NSMutableArray

startcaricanto是一个启动activityImageView的无效方法。我应该把init NSMutableArray放在哪里？@simonly在视图中初始化

NSMutableArray

有什么问题DidLoad？将data init方法放在viewController init中会更好。因为在iOS6之前，如果内存警告出现，当视图再次出现时，viewDidLoad将被调用，并且您可能会得到一个空白界面。[myArray removeAllObjects]；添加新的，然后重新加载数据也重新考虑您的命名…变量以小写字母开头，我会使用复数作为数组名称。我尝试过，但它返回一个错误：

***由于未捕获的异常“NSRangeException”终止应用程序，原因：'***-[\uu NSArrayM objectAtIndex:]：索引0超出空数组“***

很抱歉，无法了解您正在执行的操作。但这就是问题所在。您没有向我们展示的某些代码可能正在尝试读取旧数据。某些情况下，这些数据访问也应在主线程中完成（在

调度异步（调度获取主队列（），^{

）。否则，当后台队列（DISPATCH_QUEUE_PRIORITY_DEFAULT）正在清除并向这些数组添加新对象。如果UITableView试图使用其持有的旧数据，它将崩溃。