Question

我的代码：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSString *prePath = [[spineArray objectAtIndex:spineIndex - 1] spinePath];
        NSURL *preURL = [NSURL fileURLWithPath:prePath];
        UIWebView *tmpWebView = [self createWebView:preURL];
        dispatch_async(dispatch_get_main_queue(), ^{
            self.preWebView = tmpWebView;
        });

});

- (UIWebView *)createWebView:(NSURL *)url
{
UIWebView *tmpWebView = [[[UIWebView alloc] initWithFrame:CGRectMake(0, 0,kRootViewWidth, kRootViewHeight)] autorelease];
tmpWebView.delegate = self;
[tmpWebView setBackgroundColor:[UIColor whiteColor]];


currentTextSize = 100;

UISwipeGestureRecognizer *rightSwipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(gotoNextPage)];
[rightSwipeRecognizer setDirection:UISwipeGestureRecognizerDirectionLeft];

UISwipeGestureRecognizer *leftSwipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(gotoPrevPage)];
[leftSwipeRecognizer setDirection:UISwipeGestureRecognizerDirectionRight];

[tmpWebView addGestureRecognizer:rightSwipeRecognizer];
[tmpWebView addGestureRecognizer:leftSwipeRecognizer];

[rightSwipeRecognizer release];
[leftSwipeRecognizer release];

[tmpWebView loadRequest:[NSURLRequest requestWithURL:url]];
return tmpWebView;

}

当我们运行它时，提示错误是：

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...

Answer 1

您的错误确切地告诉您问题是什么This may be a result of calling to UIKit from a secondary thread.在您的createWebView方法中，您调用UIKit。当您没有在主线程上运行时，这是不允许的，在此代码示例中，您从另一个线程调用该方法。

为什么不将对该方法的调用移动到主线程上的调度？

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSString *prePath = [[spineArray objectAtIndex:spineIndex - 1] spinePath];
    NSURL *preURL = [NSURL fileURLWithPath:prePath];
    dispatch_async(dispatch_get_main_queue(), ^{
        UIWebView *tmpWebView = [self createWebView:preURL];
        self.preWebView = tmpWebView;
    });

});

GCD错误：尝试从主线程或Web线程以外的线程获取Web锁定

1 个答案: