iOS 关于键盘弹起收起的问题

1.添加监听键盘的通知

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

2.实现方法

/**
 *  键盘即将显示的时候调用
 */
- (void)keyboardWillShow:(NSNotification *)note
{
    // 1.取出键盘的frame
    CGRect begin = [note.userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue];
    
    CGRect end = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    
    // 2.取出键盘弹出的时间
    CGFloat duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    
    //3.输入框弹起后的Y
    CGFloat y_board = 0;
    
    //4.处理键盘（包括第三方键盘）
    if(begin.size.height > 0 && (begin.origin.y - end.origin.y > 0)){
        
      //处理逻辑

        y_board = end.origin.y - self.view_comment.frame.size.height;
        
        [UIView animateWithDuration:duration animations:^{
            self.view_comment.transform = CGAffineTransformMakeTranslation(0, -end.size.height);
            
            //5.让tableView上移
            if (self.tableView.contentSize.height >= y_board - self.view_comment.frame.size.height)//tableview内容的高度 > 键盘上面工具栏的Y
            {
                self.tableView.contentOffset = CGPointMake(0, self.tableView.contentSize.height - self.tableView.frame.size.height + end.size.height + self.view_comment.frame.size.height);
            }
            else if (self.tableView.contentSize.height + 80 >= y_board - self.view_comment.frame.size.height)
            {
                self.tableView.contentOffset = CGPointMake(0, 80 - (y_board - self.view_comment.frame.size.height - self.tableView.contentSize.height));
            } else
            {
                self.tableView.contentOffset = CGPointMake(0, 0);
            }
        }];
    }
    
}

/**
 *  键盘即将退出的时候调用
 */
- (void)keyboardWillHide:(NSNotification *)note
{
    // 1.取出键盘弹出的时间
    CGFloat duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    
    // 2.执行动画
    [UIView animateWithDuration:duration animations:^{
        //如果高度超过了本身高度，要让最后一个cell在底部
        [self scrollToRow];
        self.view_comment.transform = CGAffineTransformIdentity;
    }];
}

- (void)scrollToRow
{
    if (self.tableView.contentSize.height <= self.tableView.frame.size.height) {
        self.tableView.contentOffset = CGPointMake(0, 0);
    } else {
        self.tableView.contentOffset = CGPointMake(0, self.tableView.contentSize.height - self.tableView.frame.size.height);
    }
    
}