IOS 中弹框的实现方法整理 #define iOS8Later ([UIDevice currentDevice].systemVersion.doubleValue >= 8.0) ios 8以前的弹框 @interface RootViewController () @end UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@登陆失败 message:@请重新输入用户名和密码 delegate:self cancelButtonTitle:@取消 otherB