ios pop界面 键盘弹起又收回

UItextFiled:
添加UITextFieldDelegate
并使alert调用出来的textField的delegate ＝ self；
最后在alert的点击事件处添加[[alertView textFieldAtIndex:buttonIndex]resignFirstResponder];
亲测可行

1. [代码]键盘popViewControllerAnimated后再次弹起
   //返回到上一界面
   -(void)customBackBtnPressed:(id)send{

         UIAlertView *alertView=  [[UIAlertView alloc] initWithTitle:@"温馨提示" message:@"还差一步就完成注册！  确定放弃？"  delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"确定",nil];
          [alertView show];
      

   }
   //通常用的这个代理方法来做 发现键盘在popViewControllerAnimated后会重新出现
   -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{

      if (buttonIndex==1) {
          [self.navigationController popViewControllerAnimated:YES];
      }

   }

   //百思不得其姐后，后了下面这个代理方法，竟然键盘不出现了！
   -(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
   {

      if (buttonIndex==1) {
          [self.navigationController popViewControllerAnimated:YES];
      }

   }