Protocol

UIPickerViewDelegate

The delegate of a UIPickerView object must adopt this protocol and implement at least some of its methods to provide the picker view with the data it needs to construct itself.

Declaration

protocol UIPickerViewDelegate

Overview

The delegate implements the required methods of this protocol to return height, width, row title, and the view content for the rows in each component. It must also provide the content for each component’s row, either as a string or a view. Typically the delegate implements other optional methods to respond to new selections or deselections of component rows.

See UIPickerView for a discussion of components, rows, row content, and row selection.

Topics

Setting the Dimensions of the Picker View

func pickerView(UIPickerView, rowHeightForComponent: Int) -> CGFloat

Called by the picker view when it needs the row height to use for drawing row content.

func pickerView(UIPickerView, widthForComponent: Int) -> CGFloat

Called by the picker view when it needs the row width to use for drawing row content.

Setting the Content of Component Rows

The methods in this group are marked @optional. However, to use a picker view, you must implement either the pickerView(_:titleForRow:forComponent:) or the pickerView(_:viewForRow:forComponent:reusing:) method to provide the content of component rows.