iOS11键盘弹出bug

iOS11下键盘弹出覆盖输入框
打印出获得键盘高度为0
解决：
CGSize keySize = [[dic objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
换成
CGSize keySize = [[dic objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;