Picker

Kotlin |Java

open class Picker : FrameLayout

kotlin.Any
↳	android.view.View
	↳	android.view.ViewGroup
		↳	android.widget.FrameLayout
			↳	androidx.leanback.widget.picker.Picker

Known Direct Subclasses DatePicker, PinPicker, TimePicker DatePicker DatePicker is a directly subclass of Picker. PinPicker Picker subclass for allowing the user to enter a numerical PIN. TimePicker TimePicker is a direct subclass of Picker.

Picker is a widget showing multiple customized PickerColumns. The PickerColumns are initialized in setColumns(List). Call setColumnAt(int, PickerColumn) if the column value range or labels change. Call setColumnValue(int, int, boolean) to update the current value of PickerColumn.

Picker has two states and will change height:

isActivated() is true: Picker shows typically three items vertically (see getActivatedVisibleItemCount()}. Columns other than getSelectedColumn() still shows one item if the Picker is focused. On a touch screen device, the Picker will not get focus so it always show three items on all columns. On a non-touch device (a TV), the Picker will show three items only on currently activated column. If the Picker has focus, it will intercept DPAD directions and select activated column.

isActivated() is false: Picker shows one item vertically (see getVisibleItemCount()) on all columns. The size of Picker shrinks.

Summary

Nested classes
abstract	PickerValueListener Listener for Picker value changes.

Public constructors
<init>(context: Context!, attributeSet: AttributeSet!) Creates a Picker widget.
<init>(context: Context!, attrs: AttributeSet!, defStyleAttr: Int) Creates a Picker widget.

Public methods
open Unit	addOnValueChangedListener(listener: Picker.PickerValueListener!) Register a callback to be invoked when the picker's value has changed.
open Boolean	dispatchKeyEvent(event: KeyEvent!)
open Float	getActivatedVisibleItemCount() Returns number of visible items showing in a column when it's activated.
open PickerColumn!	getColumnAt(colIndex: Int) Get nth PickerColumn.
open Int	getColumnsCount() Get number of PickerColumns.
Int	getPickerItemLayoutId() Classes extending Picker can call setPickerItemLayoutId(int) to supply the Picker's item's layout id
Int	getPickerItemTextViewId() Returns the Picker's item's TextView's id from within the layout provided by Picker#getPickerItemLayoutId() or 0 if the layout provided by Picker#getPickerItemLayoutId() is a {link TextView}.
open Int	getSelectedColumn() Get current activated column index.
CharSequence!	getSeparator() Gets separator string between columns.
MutableList<CharSequence!>!	getSeparators() Returns the list of separators that will be populated between the picker column fields.
open Float	getVisibleItemCount() Returns number of visible items showing in a column when it's not activated.
open Unit	onColumnValueChanged(columnIndex: Int, newValue: Int) Classes extending Picker can override this function to supply the behavior when a list has been scrolled.
open Unit	removeOnValueChangedListener(listener: Picker.PickerValueListener!) Remove a previously installed value changed callback
open Unit	requestChildFocus(child: View!, focused: View!)
open Unit	setActivated(activated: Boolean)
open Unit	setActivatedVisibleItemCount(visiblePickerItems: Float) Changes number of visible items showing in a column when it's activated.
open Unit	setColumnAt(columnIndex: Int, column: PickerColumn!) When column labels change o