滚动时如何使 UITableView 从下到上显示？

Question

I'm looking just for general scenario.The idea is when app launches user can see only first cell of UITableView at the bottom of UIViewController. When user scrolls up full table appears and when scrolls down only first cell is displayed again. Something similar like keyboard in Facebook messenger app, but with tableView. For now I added tableView as subview to scrollView, but problem is tableView appears from top to bottom, and I'm looking for solution how to make this work upside down.. So, tableView have to appear from bottom to top of UIViewController.

Answer 1

My idea would be:

• Give your UITableView the desired frame at viewDiDLoad (probably the height of 1 cell, at the bottom of your UIView )
• Let your UIViewController implement UIScrollViewDelegate
• At - (void)scrollViewDidScroll:(UIScrollView *)scrollView of UIScrollViewDelegate check which element is scrolling (if its your UITableView ) and also check which direction user is scrolling
• Change the frame of the UITableView as you wish, you will also have to come up with some logic to block further changing of the UITableView 's frame (a BOOL would do good here I guess)

Answer 2

Not sure I understand your correctly but, maybe, this will be helpful

I believe you can try to add zero cell (or first section header view of your UITableView ) with transparent background. So that your first cell will be placed on the bottom of screen and UITableView height will be equal to screen height.

In this case, you will have only one scrolling view ( UITableView , in particularly). Following method can be used to perform expandable animation and scroll table to top to hide zero cell when user taps on first cell:

[UITableView scrollRectToVisible:animated:]

After that you can leave UITableView as it is and "constrict" your table whenever you need in the same way as it was expanded before.

Answer 3

I understand what you want to do. In general, UITableView shows cells from top to bottom.

You can add transform in tableview:

tableView.transform = CGAffineTransform(scaleX: 1, y: -1)

Then your tableview will show the cells from bottom to top and you can scroll tableview from bottom to top. But cells will be transformed as tableview, so you have to add same transform to cells also.

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    var cell: UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "cell")

    **cell.transform = tableView.transform**

    return cell
}

All done. Hope to helpful!