基础迁移-键盘弹起 收回

//监听当键盘将要出现时
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];

//监听当键将要退出时
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillHide:)
                                             name:UIKeyboardWillHideNotification
                                           object:nil];

//当键盘出现

• (void)keyboardWillShow:(NSNotification *)notification
  {
  //获取键盘的高度
  NSDictionary *userInfo = [notification userInfo];
  NSValue *value = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
  CGRect keyboardRect = [value CGRectValue];
  int height = keyboardRect.size.height;
  }

//当键退出

• (void)keyboardWillHide:(NSNotification *)notification
  {
  //获取键盘的高度
  NSDictionary *userInfo = [notification userInfo];
  NSValue *value = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
  CGRect keyboardRect = [value CGRectValue];
  int height = keyboardRect.size.height;

}