http://zhidao.baidu.com/question/198818494.html?fr=ala&device=mobile&ssid=0&from=2001a&uid=66B78AAFED4F538044236072E3A78F87&pu=usm%400%2Csz%401320_1003%2Cta%40iphone_2_4.1_1_9.2&bd_page_type=1&tj=zhidao_1_0_10_title希望这个对你有帮助!