摘要：
问题起因于一个UITextField获取到了焦点但键盘没有弹出(ios4.3以及ios5.1都有此问题), 折腾几小时后终于发现了原因.stackoverflow原帖:http://stackoverflow.com/questions/8669627/uitextviews-becomefirstresponsder-not-working-proprly"There's a known bug in iOS with resigning and becoming first responder within the same runloop. Try the follow 阅读全文