UIActivityIndi​​catorView NSURLConnection，视图未显示

Question

我在使用NSURLConnection请求帮助从服务器收集数据时显示UIActivityIndi​​catorView时出现问题。

我认为请求是异步的，即在新线程中启动。我复制了Apple的AdvancedTableViewCells示例。我在iOS 4.3 iPhone模拟器中的XCode中运行它。我还没有在真正的iPhone上测试它。

此外，我搜索了这个问题并尝试了很多建议，但感觉是我忘记了一些基本的东西。下面是我的RootViewController类的代码。

我只是选择一行，创建并添加activityview，startanimating，然后创建NSUrlConnection对象，该对象开始从另一个线程中的服务器获取数据，我相信。

有什么想法吗？

@interface RootViewController : UITableViewController {
    NSMutableData *receivedData;
    UIActivityIndicatorView *activityView;
}

@end

...

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    // In my rootviewcontroller
    activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

    [self.view addSubview:activityView];
    [activityView startAnimating];
    …

    NSMutableURLRequest *tUrlRequest = [tQuery createUrlRequest:tStatId];
    NSURLConnection *tConnectionResponse = [[NSURLConnection alloc] initWithRequest: tUrlRequest delegate: self];

    if (!tConnectionResponse) {
        NSLog(@"Failed to submit request");
    } else {
        NSLog(@"Request submitted");
        receivedData = [[NSMutableData data] retain];
    }
    return;
}

...

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

    NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);

    NSXMLParser *tParser = [[NSXMLParser alloc] initWithData: receivedData];
    ...

    [tParser parse]; 
    ...

    [connection release];
    [receivedData release];

    [NSThread sleepForTimeInterval: 2.0]; // Just to see if activity view will show up...

    NSUInteger row = 1;  
    if (row != NSNotFound) 
    { 
        // Create the view controller and initialize it with the 
        // next level of data. 
        VivadataTViewController *vivaViewController = [[VivadataTViewController alloc] init];

        if (activityView != nil) {
            [activityView stopAnimating];
        }
    }
}

Answer 1

如果出现同样的问题，请尝试更改属性检查器下的 UIActivityIndi​​catorView 的颜色 - ＆gt; 样式到灰色