iOS获取系统键盘高度和动画时间

//添加通知
-(void)addKeyBoardShowAndHideNotification
{
    //注册键盘出现的通知
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification object:nil];
    //注册键盘消失的通知
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification object:nil];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

//键盘显示回调方法
- (void)keyboardWillShow:(NSNotification *)notification {
    //获取系统键盘rect
    NSDictionary* userInfo = [notification userInfo];
    NSValue* keyboardFrameValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardRect = [keyboardFrameValue CGRectValue];
    //获得系统键盘弹出时间
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];

}

//键盘隐藏回调方法
- (void)keyboardWillHide:(NSNotification *)notification {
    //获得系统键盘弹出时间
    NSDictionary* userInfo = [notification userInfo];
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];
    
}