added in version 24.1.0
belongs to Maven artifact com.android.support:recyclerview-v7:28.0.0-alpha1

ItemTouchHelper

public class ItemTouchHelper
extends RecyclerView.ItemDecoration implements RecyclerView.OnChildAttachStateChangeListener

java.lang.Object
↳	android.support.v7.widget.RecyclerView.ItemDecoration
	↳	android.support.v7.widget.helper.ItemTouchHelper

This is a utility class to add swipe to dismiss and drag & drop support to RecyclerView.

It works with a RecyclerView and a Callback class, which configures what type of interactions are enabled and also receives events when user performs these actions.

Depending on which functionality you support, you should override onMove(RecyclerView, ViewHolder, ViewHolder) and / or onSwiped(ViewHolder, int).

This class is designed to work with any LayoutManager but for certain situations, it can be optimized for your custom LayoutManager by extending methods in the ItemTouchHelper.Callback class or implementing ItemTouchHelper.ViewDropHandler interface in your LayoutManager.

By default, ItemTouchHelper moves the items' translateX/Y properties to reposition them. You can customize these behaviors by overriding onChildDraw(Canvas, RecyclerView, ViewHolder, float, float, int, boolean) or onChildDrawOver(Canvas, RecyclerView, ViewHolder, float, float, int, boolean).

Most of the time you only need to override onChildDraw.

Summary

Nested classes
`class`	`ItemTouchHelper.Callback` This class is the contract between ItemTouchHelper and your application.
`class`	`ItemTouchHelper.SimpleCallback` A simple wrapper to the default Callback which you can construct with drag and swipe directions and this class will handle the flag callbacks.
`interface`	`ItemTouchHelper.ViewDropHandler` An interface which can be implemented by LayoutManager for better integration with `ItemTouchHelper`.

Constants
`int`	`ACTION_STATE_DRAG` A View is currently being dragged.
`int`	`ACTION_STATE_IDLE` ItemTouchHelper is in idle state.
`int`	`ACTION_STATE_SWIPE` A View is currently being swiped.
`int`	`ANIMATION_TYPE_DRAG` Animation type for views that were dragged and now will animate to their final position.
`int`	`ANIMATION_TYPE_SWIPE_CANCEL` Animation type for views which are not completely swiped thus will animate back to their original position.
`int`	`ANIMATION_TYPE_SWIPE_SUCCESS` Animation type for views which are swiped successfully.
`int`	`DOWN` Down direction, used for swipe & drag control.
`int`	`END` Horizontal end direction.
`int`	`LEFT` Left direction, used for swipe & drag control.
`int`	`RIGHT` Right direction, used for swipe & drag control.
`int`	`START` Horizontal start direction.
`int`	`UP` Up direction, used for swipe & drag control.

Public constructors
`ItemTouchHelper(ItemTouchHelper.Callback callback)` Creates an ItemTouchHelper that will work with the given Callback.

Public methods
`void`	`attachToRecyclerView(RecyclerView recyclerView)` Attaches the ItemTouchHelper to the provided RecyclerView.
`void`	`getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state)` Retrieve any offsets for the given item.
`void`	`onChildViewAttachedToWindow(View view)` Called when a view is attached to the RecyclerView.
`void`	`onChildViewDetachedFromWindow(View view)` Called when a view is detached from RecyclerView.
`void`	`onDraw(Canvas c, RecyclerView parent, RecyclerView.State state)` Draw any appropriate decorations into the Canvas supplied to the RecyclerView.
`void`	`onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state)` Draw any appropriate decorations into the Canvas supplied to the RecyclerView.
`void`	`startDrag(RecyclerView.ViewHolder viewHolder)` Starts dragging the provided ViewHolder.
`void`	`startSwipe(RecyclerView.ViewHolder viewHolder)` Starts swiping the provided ViewHolder.

Inherited methods

From class


  
    android.support.v7.widget.RecyclerView.ItemDecoration

From class


  
    java.lang.Object

From interface


  
    android.support.v7.widget.RecyclerView.OnChildAttachStateChangeListener

Constants

ACTION_STATE_DRAG

added in version 24.1.0

int ACTION_STATE_DRAG

A View is currently being dragged.

Constant Value: 2 (0x00000002)

ACTION_STATE_IDLE

added in version 24.1.0

int ACTION_STATE_IDLE

ItemTouchHelper is in idle state. At this state, either there is no related motion event by the user or latest motion events have not yet triggered a swipe or drag.

Constant Value: 0 (0x00000000)

ACTION_STATE_SWIPE

added in version 24.1.0

int ACTION_STATE_SWIPE

A View is currently being swiped.

Constant Value: 1 (0x00000001)

ANIMATION_TYPE_DRAG

added in version 24.1.0

int ANIMATION_TYPE_DRAG

Animation type for views that were dragged and now will animate to their final position.

Constant Value: 8 (0x00000008)

ANIMATION_TYPE_SWIPE_CANCEL

added in version 24.1.0

int ANIMATION_TYPE_SWIPE_CANCEL

Animation type for views which are not completely swiped thus will animate back to their original position.

Constant Value: 4 (0x00000004)

ANIMATION_TYPE_SWIPE_SUCCESS

added in version 24.1.0

int ANIMATION_TYPE_SWIPE_SUCCESS

Animation type for views which are swiped successfully.

Constant Value: 2 (0x00000002)

DOWN

added in version 24.1.0

int DOWN

Down direction, used for swipe & drag control.

Constant Value: 2 (0x00000002)

END

added in version 24.1.0

int END

Horizontal end direction. Resolved to LEFT or RIGHT depending on RecyclerView's layout direction. Used for swipe & drag control.

Constant Value: 32 (0x00000020)

LEFT

added in version 24.1.0

int LEFT

Left direction, used for swipe & drag control.

Constant Value: 4 (0x00000004)

RIGHT

added in version 24.1.0

int RIGHT

Right direction, used for swipe & drag control.

Constant Value: 8 (0x00000008)

START

added in version 24.1.0

int START

Horizontal start direction. Resolved to LEFT or RIGHT depending on RecyclerView's layout direction. Used for swipe & drag control.

Constant Value: 16 (0x00000010)

UP

added in version 24.1.0

int UP

Up direction, used for swipe & drag control.

Constant Value: 1 (0x00000001)

Public constructors