异步加载加载web网页

dispatch_queue_t queue = dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0

);

   

dispatch_async

(queue, ^{

       

NSURLRequest *request =[ NSURLRequest requestWithURL:[ NSURL URLWithString: @" http:// "

]];

        [

_webView loadRequest

:request];

       

NSLog( @" 使用异步函数执行主队列中的任务 1--%@",[ NSThread currentThread

]);

       

dispatch_async( dispatch_get_main_queue

(), ^{

            [

self. view addSubview: _webView

];

           

NSLog( @" 使用异步函数执行主队列中的任务 2--%@",[ NSThread currentThread

]);

        });

    });