ios - 如何在 Objective-C 中异步获取 API 数据？

Question

我所有的工作都很顺利，但是有一点问题。我在 -(void)viewDidLoad{} 中有我的 NSURLRequest，它花了一些时间从服务器获取数据。我希望它以异步方式完成。

以下是我的代码，请建议我应该实现什么。？在此先感谢大家。 :)

- (void)viewDidLoad {
[super viewDidLoad];
[[self tableView2]setDelegate:self ];
[[self tableView2]setDataSource:self];
array=[[NSMutableArray alloc]init];

NSString *castString = [NSString stringWithFormat:@"https://api.themoviedb.org/3/movie/%@/credits?api_key=c4bd81709e87b12e6c74a08609433c49",movieIDinString];
NSURL *url=[NSURL URLWithString:castString];

NSURLRequest *request=[NSURLRequest requestWithURL:url];
connection=[NSURLConnection connectionWithRequest:request delegate:self];
if (connection)
{
    webData=  [[NSMutableData alloc]init];
}

Answer 1

试试这个..

  dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
        //Background Thread

       NSString *castString = [NSString stringWithFormat:@"https://api.themoviedb.org/3/movie/%@/credits?api_key=c4bd81709e87b12e6c74a08609433c49",movieIDinString];
        NSURL *url=[NSURL URLWithString:castString];

        NSURLRequest *request=[NSURLRequest requestWithURL:url];
        connection=[NSURLConnection connectionWithRequest:request delegate:self];
        if (connection)
        {
            webData=  [[NSMutableData alloc]init];
        }

        dispatch_async(dispatch_get_main_queue(), ^(void){
            //Run UI Updates

// reload table view here
            [_activityIndicatorImageView stopAnimating];
        });
    });