Instance Method

tableView(_:estimatedHeightForRowAt:)

Asks the delegate for the estimated height of a row in a specified location.

Declaration

optional func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat

Parameters

tableView

The table-view object requesting this information.

indexPath

An index path that locates a row in tableView.

Return Value

A nonnegative floating-point value that estimates the height (in points) that row should be. Return automaticDimension if you have no estimate.

Discussion

Providing an estimate the height of rows can improve the user experience when loading the table view. If the table contains variable height rows, 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.

See Also

Estimating Heights for the Table's Content

func tableView(UITableView, estimatedHeightForHeaderInSection: Int) -> CGFloat

Asks the delegate for the estimated height of the header of a particular section.

func tableView(UITableView, estimatedHeightForFooterInSection: Int) -> CGFloat

Asks the delegate for the estimated height of the footer of a particular section.