Asks the delegate for the estimated height of the header of a particular section.
- iOS 7.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
The table-view object requesting this information.
An index number identifying a section of
A nonnegative floating-point value that specifies the height (in points) of the header for
Providing an estimate the height of section headers can improve the user experience when loading the table view. If the table contains variable height section headers, it might be expensive to calculate all their heights and so lead to a longer load time. Using estimation allows you to defer some of the cost of geometry calculation from load time to scrolling time.