ohho ohho - 5 months ago 78
iOS Question

How to position UITableViewCell at bottom of screen?

There are one to three

UITableViewCell
s in a
UITableViewView
. Is there a way to always position the cell(s) at the bottom of screen after
reloadData
?

+----------------+ +----------------+ +----------------+
| | | | | |
| | | | | |
| | | | | |
| | | | | +------------+ |
| | | | | | cell 1 | |
| | | | | +------------+ |
| | | +------------+ | | +------------+ |
| | | | cell 1 | | | | cell 2 | |
| | | +------------+ | | +------------+ |
| +------------+ | | +------------+ | | +------------+ |
| | cell 1 | | | | cell 2 | | | | cell 3 | |
| +------------+ | | +------------+ | | +------------+ |
+----------------+ +----------------+ +----------------+

Answer

I've create a new sample solution since the previous answer is not outdated for modern use.

The latest technique uses autolayout and self-sizing cells so the previous answer would no longer work. I reworked the solution to work with the modern features and created a sample project to put on GitHub.

Instead of counting up the height of each row, which is causes additional work, this code instead gets the frame for the last row so that the content inset from the top can be calculated. It leverages what the table view is already doing so no additional work is necessary.

This code also only sets the top inset in case the bottom inset is set for the keyboard or another overlay.

Please report any bugs or submit improvements on GitHub and I will update this sample.

GitHub: https://github.com/brennanMKE/BottomTable

- (void)updateContentInsetForTableView:(UITableView *)tableView animated:(BOOL)animated {
    NSUInteger lastRow = [self tableView:tableView numberOfRowsInSection:0];
    NSUInteger lastIndex = lastRow > 0 ? lastRow - 1 : 0;

    NSIndexPath *lastIndexPath = [NSIndexPath indexPathForItem:lastIndex inSection:0];
    CGRect lastCellFrame = [self.tableView rectForRowAtIndexPath:lastIndexPath];

    // top inset = table view height - top position of last cell - last cell height
    CGFloat topInset = MAX(CGRectGetHeight(self.tableView.frame) - lastCellFrame.origin.y - CGRectGetHeight(lastCellFrame), 0);

    UIEdgeInsets contentInset = tableView.contentInset;
    contentInset.top = topInset;

    UIViewAnimationOptions options = UIViewAnimationOptionBeginFromCurrentState;
    [UIView animateWithDuration:animated ? 0.25 : 0.0 delay:0.0 options:options animations:^{
        tableView.contentInset = contentInset;
    } completion:^(BOOL finished) {
    }];
}
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