代码：
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//在后台进行网址的解析操作
NSURL * url = [NSURL URLWithString:@"http://www.baidu.com"];
NSError * error;
NSString * data = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
if (data != nil) {
dispatch_async(dispatch_get_main_queue(), ^{
//成功，跳转回主界面
NSLog(@"call back, the data is: %@", data);
});
} else {
//失败，返回失败提示。
NSLog(@"error when download:%@", error);
}
});
}
输出：
2015-07-15 21:51:37.902 CGD-使用[1719:81744] call back, the data is: <html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head><body style='margin:0px;overflow-x:hidden;overflow-y:hidden;'><iframe id='i' src="http://www.baidu.com/?tn=96181616_hao_pg" scrolling=auto width='100%' height='100%' frameborder='no' onload=''style='position:fixed;'></iframe></body></html>
参考资料
http://www.cnblogs.com/pure/archive/2013/03/31/2977420.html