Creating UITableViewCells with dynamic height based upon Auto Layout constraints with iOS 8

gistfile1.m

# pragma mark - Cell Setup

- (void)setUpCell:(DynamicTableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath {
    cell.label.text = [self.dataSource objectAtIndex:indexPath.row];
}

# pragma mark - UITableViewControllerDelegate

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.dataSource.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    DynamicTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    [self setUpCell:cell atIndexPath:indexPath];

    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    static DynamicTableViewCell *cell = nil;
    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{
        cell = [self.tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    });

    [self setUpCell:cell atIndexPath:indexPath];

    return [self calculateHeightForConfiguredSizingCell:cell];
}

- (CGFloat)calculateHeightForConfiguredSizingCell:(UITableViewCell *)sizingCell {
    [sizingCell layoutIfNeeded];

    CGSize size = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    return size.height;
}