错误消息，UIKit不应该从辅助线程调用 [英] Error message that UIKit should not be called from a secondary thread

问题描述

我有一个应用程序使用 UISearchBar 根据用户输入从外部API动态搜索。

I have an app which uses a UISearchBar to dynamically search from an external API based on user input.

应用程序正在搜索外部API并正确显示结果，但当我从搜索结果中选择任何行时，屏幕冻结，我收到此错误; / p>

The app is searching the external API fine and displaying results correctly, but when I select any row from the search results, the screen freezes and I am getting this error;

尝试从主线程或网络线程之外的线程获取Web锁
UIKit不应从次要线程

Tried to obtain the web lock from a thread other than the main thread or the web thread UIKit should not be called from a secondary thread

我完全不知道如何解决这个问题。

I have absolutely no idea how I can fix this.

以下是代码：

- (void) run: (id) param  {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL: [self URL]];
    [parser setDelegate: self];
    [parser parse];
    [parser release];
    [delegate parseDidComplete];
    [pool release];
} 

- (void) parseXMLFile: (NSURL *) url
{ 
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    [self setURL: url];
    NSThread* myThread = [[NSThread alloc] initWithTarget:self
                                                 selector:@selector(run
   object: nil];
    [myThread start];
    [pool release];
}

推荐答案

尝试从
线程而不是主线程或
获取Web锁UIKit不应该是从辅助线程调用

"Tried to obtain the web lock from a thread other than the main thread or the web thread UIKit should not be called from a secondary thread"

修复在概念上很简单;不要从您的线程更新UI。

The fix is conceptually simple; don't update the UI from your thread.

parseDidComplete 是消息来源，那么这样的东西将工作：

Assuming the parseDidComplete is where the message is sourced, then something like this will "work":

[delegate performSelectorOnMainThread: @selector(parseDidComplete) withObject: nil waitUntilDone: YES];

Work，因为线程很难，这个答案完全忽略了你可能遇到的任何同步问题。

"Work" because threading is hard and this answer completely ignores any synchronization issues you might have.

注意你最好使用 NSOperation 和 NSOperationQueue 。他们有很多文件，有很多例子。

Note that you'd be better off using NSOperation and NSOperationQueue. They are well documented and there are a bunch of examples.

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