键盘弹出的时间

    // 键盘最终的frame
    CGRect keyboardF = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    
    // 动画时间
    CGFloat duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    
    [UIView animateWithDuration:duration animations:^{
        
    }];