下拉以显示视图

Question

我有UITableView.我想添加一个UITextField上面的tableView,可以通过拉下tableView来访问它.我想通过拉取tableView来隐藏我的textField.我怎样才能做到这一点？这是我试过的:

[self.messagesTableView addSubview:self.messageField];

- (UITextField*)messageField
{
    if (!_messageField)
    {
        _messageField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, self.messagesTableView.frame.size.width, kMessageFieldHeight)];
        _messageField.autoresizingMask = UIViewAutoresizingFlexibleWidth;
        _messageField.backgroundColor = [UIColor greenColor];
    }
    return _messageField;
}

- (void)scrollViewDidScroll:(UIScrollView*)scrollView
{
    if (scrollView == self.messagesTableView)
    {
        CGRect newFrame = self.messagesTableView.frame;
        newFrame.origin.y = self.messagesTableView.contentOffset.y + kMessageFieldHeight;
        self.messagesTableView.frame = newFrame;
    }
}

Answer 1

我在我的应用程序中完成了这样的功能.我做了什么只是按照步骤.

1)添加one view to negative position of tableView.在此视图中,您可以根据需要随意添加textField或按钮.

UIView *viewForSearchBar = [[UIView alloc]initWithFrame:CGRectMake(0, -50, 320, 50)];
viewForSearchBar.backgroundColor = [UIColor clearColor];
[self._tableView addSubview:viewForSearchBar];
self._tableView.contentInset = UIEdgeInsetsMake(50, 0, 0, 0);

2)现在当用户开始拖动tableview(表视图的实际滚动视图)时,你可以调用scrollview的委托方法来测试它.

当你向下拖动/滚动tableView时,你会得到contentOffset.y将小于0,我在这里用代码解释.

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

    if (decelerate) {
        [txtSearch resignFirstResponder];
    }

    id<UILayoutSupport> topLayoutGuide = self.topLayoutGuide;
    if(scrollView.contentOffset.y < 0)
    {
        UIView* hiddenHeader = ...; // this points to the hidden header view above
        CGRect headerFrame = [hiddenHeader frame];

        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:0.2];
        self._tableView.contentInset = UIEdgeInsetsMake(headerFrame.size.height + [topLayoutGuide length], 0, 0, 0);

        [UIView commitAnimations];
    } else {
        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:0.2];

        self._tableView.contentInset = UIEdgeInsetsMake([topLayoutGuide length], 0, 0, 0);

        [UIView commitAnimations];   
    }
}

正如我已实施的那样,这两个步骤对我来说很好.让我添加图片来验证它.

如果您还有任何疑问,可以问我.