iOS 键盘的监听 调整view的位置

iOS在处理键盘的出现和消失时需要监听UIKeyboardWillChangeFrameNotifications/UIKeyboardDidHideNotifications

- (void)viewDidLoad
{
    [super viewDidLoad];

//添加监听 键盘消失
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDown) name:UIKeyboardDidHideNotification object:nil];

//添加监听 键盘出现
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
}

- (void)keyboardWillChangeFrame:(NSNotification *)noti{

//取出键盘动画的时间(根据userInfo的key-UIKeyboardAnimationDurationUserInfoKey)

    CGFloat duration = [noti.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue];

 //取得键盘最后的frame(根据userInfo的key----UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 227}, {320, 253}}";)

    CGRect keyboardFrame = [noti.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

//处理键盘出现的是页面的变化。。。。。。
}

- (void)keyboardDown
{
    //处理键盘消失是页面的变化 。。。。。。
}