DataObserver

Kotlin |Java

abstract class DataObserver

kotlin.Any
↳	androidx.leanback.widget.ObjectAdapter.DataObserver

A DataObserver can be notified when an ObjectAdapter's underlying data changes. Separate methods provide notifications about different types of changes.

Summary

Public constructors
`<init>()` A DataObserver can be notified when an ObjectAdapter's underlying data changes.

Public methods
open Unit	`onChanged()` Called whenever the ObjectAdapter's data has changed in some manner outside of the set of changes covered by the other range-based change notification methods.
open Unit	`onItemMoved(fromPosition: Int, toPosition: Int)` Called when an item is moved from one position to another position
open Unit	`onItemRangeChanged(positionStart: Int, itemCount: Int)` Called when a range of items in the ObjectAdapter has changed.
open Unit	`onItemRangeChanged(positionStart: Int, itemCount: Int, payload: Any!)` Called when a range of items in the ObjectAdapter has changed.
open Unit	`onItemRangeInserted(positionStart: Int, itemCount: Int)` Called when a range of items is inserted into the ObjectAdapter.
open Unit	`onItemRangeRemoved(positionStart: Int, itemCount: Int)` Called when a range of items is removed from the ObjectAdapter.

Public constructors

<init>

DataObserver()

A DataObserver can be notified when an ObjectAdapter's underlying data changes. Separate methods provide notifications about different types of changes.

Public methods

onChanged

open fun onChanged(): Unit

Called whenever the ObjectAdapter's data has changed in some manner outside of the set of changes covered by the other range-based change notification methods.

onItemMoved

open fun onItemMoved(
    fromPosition: Int, 
    toPosition: Int
): Unit

Called when an item is moved from one position to another position

Parameters
`fromPosition`	Int: Previous position of the item.
`toPosition`	Int: New position of the item.

onItemRangeChanged

open fun onItemRangeChanged(
    positionStart: Int, 
    itemCount: Int
): Unit

Called when a range of items in the ObjectAdapter has changed. The basic ordering and structure of the ObjectAdapter has not changed.

Parameters
`positionStart`	Int: The position of the first item that changed.
`itemCount`	Int: The number of items changed.

onItemRangeChanged

open fun onItemRangeChanged(
    positionStart: Int, 
    itemCount: Int, 
    payload: Any!
): Unit

Called when a range of items in the ObjectAdapter has changed. The basic ordering and structure of the ObjectAdapter has not changed.

Parameters
`positionStart`	Int: The position of the first item that changed.
`itemCount`	Int: The number of items changed.
`payload`	Any!: Optional parameter, use null to identify a "full" update.

onItemRangeInserted

open fun onItemRangeInserted(
    positionStart: Int, 
    itemCount: Int
): Unit

Called when a range of items is inserted into the ObjectAdapter.

Parameters
`positionStart`	Int: The position of the first inserted item.
`itemCount`	Int: The number of items inserted.

onItemRangeRemoved

open fun onItemRangeRemoved(
    positionStart: Int, 
    itemCount: Int
): Unit

Called when a range of items is removed from the ObjectAdapter.

Parameters
`positionStart`	Int: The position of the first removed item.
`itemCount`	Int: The number of items removed.