Objective c UIRefreshControl不刷新xml数据

我是新来的，尝试添加一个pull-to-refresh控件来更新我的xml表视图时遇到了麻烦。我得到了刷新动画的正确拉力，但数据没有刷新。请帮忙

- (void)viewDidLoad {
    [super viewDidLoad];
    feeds = [[NSMutableArray alloc] init];
    NSURL *url = [NSURL URLWithString:@"http://www.PLACEHOLDER.rss.xml"];
    parser = [[NSXMLParser alloc] initWithContentsOfURL:url];
    [parser setDelegate:self];
    [parser setShouldResolveExternalEntities:NO];
    [parser parse];
    UIRefreshControl *refreshControl = [UIRefreshControl new];
    [refreshControl addTarget:self action:@selector(refresh:) 
        forControlEvents:UIControlEventValueChanged];
    refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"Pull 
        to refresh..."];
    self.refreshControl = refreshControl;

}

- (void)refresh:(UIRefreshControl *)sender {
    // ...refresh code
    NSURL *url = [NSURL URLWithString:@"http://www.PLACEHOLDER.rss.xml"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    (void)[[NSURLConnection alloc] initWithRequest:request delegate:self];

    [sender endRefreshing];
}

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当下载完成或XML已完成解析时，您没有包含相关的委托方法。当您的请求完成时，是否在委托方法中调用[self.tableView reloadData]？我对此不熟悉。你能提供更多关于如何做到这一点的细节吗。谢谢你们两位的更新。