Asks the delegate for the size of the footer view in the specified section.
- macOS 10.11+
The collection view object displaying the flow layout.
The layout object requesting the information.
The index of the section whose footer size is requested.
The size of the footer. Return
NSZero if you do not want a footer added to the section.
If you implement this method, the flow layout object calls it to obtain the size of the footer in each section and uses that information to set the size of the corresponding views. If you do not implement this method, the footer size is obtained from the properties of the flow layout object.
The flow layout object uses only one of the returned size values. For a vertically scrolling layout, the layout object uses the height value. For a horizontally scrolling layout, the layout object uses the width value. The other value is sized appropriately to match the opposing dimension of the collection view itself. Set the size of the footer to
0 to prevent it from being displayed.