ios键盘高度监听

- (void)keyboardNotifiation{
//注册键盘出现的通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotification object:nil];
//键盘变化
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillChange:)
name:UIKeyboardWillChangeFrameNotification object:nil];
//键盘退出
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillBeHidden:) name:UIKeyboardWillHideNotification object:nil];
}

- (void)keyboardWasShown:(NSNotification *)notification{

}

- (void)keyboardWillChange:(NSNotification *)notification{
NSDictionary *info = [notification userInfo];
CGRect beginKeyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
CGRect endKeyboardRect = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
CGFloat yOffset = endKeyboardRect.origin.y - beginKeyboardRect.origin.y;
CGPoint offset = self.tableView.contentOffset;
if (yOffset < 0) {
offset.y -= yOffset;
if (offset.y < 0) {
offset.y = 0;
}
}
[self.tableView setContentOffset:offset animated:YES];
}

- (void)keyboardWillBeHidden:(NSNotification *)notification{

}