1、注冊
UIKeyboardDidShowNotification/UIKeyboardDidHideNotification通知。

-(id) initWithNibName:(NSString*)nibNameOrNil bundle:nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {

        // 寫在這裡，或者viewDidLoad
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardShown:) name:UIKeyboardDidShowNotification object:nil];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardHidden:) name:UIKeyboardDidHideNotification object:nil];
    }
    return self;
}

-(void) dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidHideNotification object:nil];
}

2、當通知到來，調整frame。

-(void) keyboardShown:(NSNotification*) notification {
    _initialTVHeight = _tableView.frame.size.height;

    CGRect initialFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGRect convertedFrame = [self.view convertRect:initialFrame fromView:nil];
    CGRect tvFrame = _tableView.frame;
    tvFrame.size.height = convertedFrame.origin.y;
    _tableView.frame = tvFrame;
}

-(void) keyboardHidden:(NSNotification*) notification {
    CGRect tvFrame = _tableView.frame;
    tvFrame.size.height = _initialTVHeight;
    [UIView beginAnimations:@TableViewDown context:NULL];
    [UIView setAnimationDuration:0.3f];
    _tableView.frame = tvFrame;
    [UIView commitAnimations];
}

3、觸發文本框，滾動tableView
-(void) textFieldDidBeginEditing:(UITextField *)textField {
NSIndexPath* path = [NSIndexPath indexPathForRow:row inSection:section];
[self performSelector:@selector(scrollToCell:) withObject:path afterDelay:0.5f];
}
-(void) scrollToCell:(NSIndexPath*) path {
[_tableView scrollToRowAtIndexPath:path atScrollPosition:UITableViewScrollPositionNone animated:YES];
}