- (void)registerForKeyboardNotifications{    //使用NSNotificationCenter 鍵盤出現時    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillShown:)                                                name:UIKeyboardWillChangeFrameNotification object:nil];    //使用NSNotificationCenter 鍵盤隐藏時    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillBeHidden:)                                                 name:UIKeyboardWillHideNotification object:nil];}//实现当键盘出现的时候计算键盘的高度大小。用于输入框显示位置- (void)keyboardWillShown:(NSNotification*)aNotification{

NSDictionary *info = [notification userInfo];

    CGFloat duration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];

    NSValue *value = [info objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGSize keyboardSize = [value CGRectValue].size;

    

 

//输入框位置动画加载

 

    [UIView animateWithDuration:duration animations:^{

//do something

 

    }];

}

//当键盘隐藏的时候- (void)keyboardWillBeHidden:(NSNotification*)aNotification{ //do something}