Question

我的应用程序崩溃并提供如下输出：

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...
1   WebThreadLock
2   -[UIWebDocumentView(UIWebDocumentViewTextSelecting) selectionBaseWritingDirection]
3   -[UITextField _resignFirstResponder]
4   -[UIResponder _finishResignFirstResponder]
5   -[UIResponder resignFirstResponder]
6   -[UITextField resignFirstResponder]
7   -[UIView(UITextField) endEditing:]
8   -[UIWindowController _prepareKeyboardForTransition:fromView:]
9   -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:]
10  -[UIViewController presentViewController:withTransition:completion:]
11  -[UIViewController presentViewController:animated:completion:]
12  -[UIViewController presentModalViewController:animated:]
13  -[studentlogViewController parse]
14  -[NSThread main]
15  __NSThread__main__
16  _pthread_start
17  thread_start

任何人都可以让我知道，我忘记了，我不知道这里发生了什么

Answer 1

你正在后台解析一些数据（这很好）然后你从后台线程更新UI，这是错误的。您必须从主线程更新UI：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    [studentLogViewController parse];
    dispatch_async(dispatch_get_main_queue(), ^{
        // now present the new view controller
    });
});

Answer 2

如果您要进行任何UI操作，则必须在主线程上完成..

只需将编码粘贴在以下语法

中

dispatch_sync(dispatch_get_main_queue(), ^{
    //Your code goes here
});

或者您可以使用以下语法调用您的方法

[self performSelectorOnMainThread:@selector(yourmethod:)withObject:obj waitUntilDone:YES]

为什么我的代码会因某些UIWebView异常而崩溃？

2 个答案: