iphone - bool _WebTryThreadLock(bool) 与 UITableView 崩溃

Question

我正在尝试在 UITableView 中显示推文。

代码:-

- (void)requestTimeline:(int)count
{    
    NSURL *url = [NSURL URLWithString:@"http://api.twitter.com/1/statuses/user_timeline.json"];

    NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
    [parameters setObject:@"abc" forKey:@"screen_name"];
    [parameters setObject:@"20" forKey:@"count"];
    [parameters setObject:@"1" forKey:@"include_entities"];

    TWRequest *request = [[TWRequest alloc] initWithURL:url parameters:parameters requestMethod:TWRequestMethodGET];

    [request performRequestWithHandler:^(NSData *responseData1, NSHTTPURLResponse *urlResponse, NSError *error)
    {
        if (responseData1 != nil)
        {
            NSError *error = nil;
            self.itemsToDisplay = [NSJSONSerialization JSONObjectWithData:responseData1 options:NSJSONReadingMutableLeaves error:&error];

            if (self.itemsToDisplay != nil)
            {
                [self.tableView reloadData];
            }
            else
            {
                NSLog(@"Error serializing response data %@ with user info %@.", error, error.userInfo);
            }
        }
        else
        {
            NSLog(@"Error requesting timeline %@ with user info %@.", error, error.userInfo);
        }
    }];
}

self 是 UITableViewController 的子类。

由于阻塞，twitter 请求将在另一个线程而不是主线程上执行。这就是它崩溃的原因。

//TWRequest.h

// Issue the request. This block is not guaranteed to be called on any particular thread.
- (void)performRequestWithHandler:(TWRequestHandler)handler;

崩溃报告:-

bool _WebTryThreadLock(bool), 0xa8e4f50: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now...

如何解决这个问题？

谢谢...

Answer 1

Web View 只能在主线程中使用。大部分 UIKit —— tableView reloadData 命令也不是线程安全的

dispatch_async(dispatch_get_main_queue(), ^{ 
    //all you ever do with UIKit.. in your case the reloadData call
    [self.tableView reloadData];
});