ItemTouchHelper.Callback

public abstract class ItemTouchHelper.Callback

Known direct subclasses
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.


This class is the contract between ItemTouchHelper and your application. It lets you control which touch behaviors are enabled per each ViewHolder and also receive callbacks when user performs these actions.

To control which actions user can take on each view, you should override getMovementFlags and return appropriate set of direction flags. (LEFT, RIGHT, START, END, UP, DOWN). You can use makeMovementFlags to easily construct it. Alternatively, you can use SimpleCallback.

If user drags an item, ItemTouchHelper will call onMove(recyclerView, dragged, target). Upon receiving this callback, you should move the item from the old position (dragged.getAdapterPosition()) to new position (target.getAdapterPosition()) in your adapter and also call notifyItemMoved. To control where a View can be dropped, you can override canDropOver. When a dragging View overlaps multiple other views, Callback chooses the closest View with which dragged View might have changed positions. Although this approach works for many use cases, if you have a custom LayoutManager, you can override chooseDropTarget to select a custom drop target.

When a View is swiped, ItemTouchHelper animates it until it goes out of bounds, then calls onSwiped. At this point, you should update your adapter (e.g. remove the item) and call related Adapter#notify event.

Summary

Constants

static final int
static final int

Public constructors

Public methods

boolean
canDropOver(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder current,
    @NonNull RecyclerView.ViewHolder target
)

Return true if the current ViewHolder can be dropped over the the target ViewHolder.

RecyclerView.ViewHolder
chooseDropTarget(
    @NonNull RecyclerView.ViewHolder selected,
    @NonNull List<RecyclerView.ViewHolder> dropTargets,
    int curX,
    int curY
)

Called by ItemTouchHelper to select a drop target from the list of ViewHolders that are under the dragged View.

void
clearView(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder
)

Called by the ItemTouchHelper when the user interaction with an element is over and it also completed its animation.

int
convertToAbsoluteDirection(int flags, int layoutDirection)

Converts a given set of flags to absolution direction which means START and END are replaced with LEFT and RIGHT depending on the layout direction.

static int
convertToRelativeDirection(int flags, int layoutDirection)

Replaces a movement direction with its relative version by taking layout direction into account.

long
getAnimationDuration(
    @NonNull RecyclerView recyclerView,
    int animationType,
    float animateDx,
    float animateDy
)

Called by the ItemTouchHelper when user action finished on a ViewHolder and now the View will be animated to its final position.

int

When finding views under a dragged view, by default, ItemTouchHelper searches for views that overlap with the dragged View.

static @NonNull ItemTouchUIUtil

Returns the ItemTouchUIUtil that is used by the Callback class for visual changes on Views in response to user interactions.

float

Returns the fraction that the user should move the View to be considered as it is dragged.

abstract int
getMovementFlags(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder
)

Should return a composite flag which defines the enabled move directions in each state (idle, swiping, dragging).

float
getSwipeEscapeVelocity(float defaultValue)

Defines the minimum velocity which will be considered as a swipe action by the user.

float

Returns the fraction that the user should move the View to be considered as swiped.

float
getSwipeVelocityThreshold(float defaultValue)

Defines the maximum velocity ItemTouchHelper will ever calculate for pointer movements.

int
interpolateOutOfBoundsScroll(
    @NonNull RecyclerView recyclerView,
    int viewSize,
    int viewSizeOutOfBounds,
    int totalSize,
    long msSinceStartScroll
)

Called by the ItemTouchHelper when user is dragging a view out of bounds.

boolean

Returns whether ItemTouchHelper should start a swipe operation if a pointer is swiped over the View.

boolean

Returns whether ItemTouchHelper should start a drag and drop operation if an item is long pressed.

static int
makeFlag(int actionState, int directions)

Shifts the given direction flags to the offset of the given action state.

static int
makeMovementFlags(int dragFlags, int swipeFlags)

Convenience method to create movement flags.

void
onChildDraw(
    @NonNull Canvas c,
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    float dX,
    float dY,
    int actionState,
    boolean isCurrentlyActive
)

Called by ItemTouchHelper on RecyclerView's onDraw callback.

void
onChildDrawOver(
    @NonNull Canvas c,
    @NonNull RecyclerView recyclerView,
    RecyclerView.ViewHolder viewHolder,
    float dX,
    float dY,
    int actionState,
    boolean isCurrentlyActive
)

Called by ItemTouchHelper on RecyclerView's onDraw callback.

abstract boolean
onMove(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    @NonNull RecyclerView.ViewHolder target
)

Called when ItemTouchHelper wants to move the dragged item from its old position to the new position.

void
onMoved(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    int fromPos,
    @NonNull RecyclerView.ViewHolder target,
    int toPos,
    int x,
    int y
)

Called when onMove returns true.

void
onSelectedChanged(
    @Nullable RecyclerView.ViewHolder viewHolder,
    int actionState
)

Called when the ViewHolder swiped or dragged by the ItemTouchHelper is changed.

abstract void
onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction)

Called when a ViewHolder is swiped by the user.

Constants

DEFAULT_DRAG_ANIMATION_DURATION

Added in 1.0.0
public static final int DEFAULT_DRAG_ANIMATION_DURATION = 200

DEFAULT_SWIPE_ANIMATION_DURATION

Added in 1.0.0
public static final int DEFAULT_SWIPE_ANIMATION_DURATION = 250

Public constructors

Callback

Added in 1.0.0
public Callback()

Public methods

canDropOver

Added in 1.0.0
public boolean canDropOver(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder current,
    @NonNull RecyclerView.ViewHolder target
)

Return true if the current ViewHolder can be dropped over the the target ViewHolder.

This method is used when selecting drop target for the dragged View. After Views are eliminated either via bounds check or via this method, resulting set of views will be passed to chooseDropTarget.

Default implementation returns true.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView to which ItemTouchHelper is attached to.

@NonNull RecyclerView.ViewHolder current

The ViewHolder that user is dragging.

@NonNull RecyclerView.ViewHolder target

The ViewHolder which is below the dragged ViewHolder.

Returns
boolean

True if the dragged ViewHolder can be replaced with the target ViewHolder, false otherwise.

chooseDropTarget

Added in 1.0.0
public RecyclerView.ViewHolder chooseDropTarget(
    @NonNull RecyclerView.ViewHolder selected,
    @NonNull List<RecyclerView.ViewHolder> dropTargets,
    int curX,
    int curY
)

Called by ItemTouchHelper to select a drop target from the list of ViewHolders that are under the dragged View.

Default implementation filters the View with which dragged item have changed position in the drag direction. For instance, if the view is dragged UP, it compares the view.getTop() of the two views before and after drag started. If that value is different, the target view passes the filter.

Among these Views which pass the test, the one closest to the dragged view is chosen.

This method is called on the main thread every time user moves the View. If you want to override it, make sure it does not do any expensive operations.

Parameters
@NonNull RecyclerView.ViewHolder selected

The ViewHolder being dragged by the user.

@NonNull List<RecyclerView.ViewHolder> dropTargets

The list of ViewHolder that are under the dragged View and candidate as a drop.

int curX

The updated left value of the dragged View after drag translations are applied. This value does not include margins added by RecyclerView.ItemDecorations.

int curY

The updated top value of the dragged View after drag translations are applied. This value does not include margins added by RecyclerView.ItemDecorations.

Returns
RecyclerView.ViewHolder

A ViewHolder to whose position the dragged ViewHolder should be moved to.

clearView

Added in 1.0.0
public void clearView(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder
)

Called by the ItemTouchHelper when the user interaction with an element is over and it also completed its animation.

This is a good place to clear all changes on the View that was done in onSelectedChanged, onChildDraw or onChildDrawOver.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView which is controlled by the ItemTouchHelper.

@NonNull RecyclerView.ViewHolder viewHolder

The View that was interacted by the user.

convertToAbsoluteDirection

Added in 1.0.0
public int convertToAbsoluteDirection(int flags, int layoutDirection)

Converts a given set of flags to absolution direction which means START and END are replaced with LEFT and RIGHT depending on the layout direction.

Parameters
int flags

The flag value that include any number of movement flags.

int layoutDirection

The layout direction of the RecyclerView.

Returns
int

Updated flags which includes only absolute direction values.

convertToRelativeDirection

Added in 1.0.0
public static int convertToRelativeDirection(int flags, int layoutDirection)

Replaces a movement direction with its relative version by taking layout direction into account.

Parameters
int flags

The flag value that include any number of movement flags.

int layoutDirection

The layout direction of the View. Can be obtained from getLayoutDirection.

Returns
int

Updated flags which uses relative flags (START, END) instead of LEFT, RIGHT.

getAnimationDuration

Added in 1.0.0
public long getAnimationDuration(
    @NonNull RecyclerView recyclerView,
    int animationType,
    float animateDx,
    float animateDy
)

Called by the ItemTouchHelper when user action finished on a ViewHolder and now the View will be animated to its final position.

Default implementation uses ItemAnimator's duration values. If animationType is ANIMATION_TYPE_DRAG, it returns getMoveDuration, otherwise, it returns getRemoveDuration. If RecyclerView does not have any RecyclerView.ItemAnimator attached, this method returns DEFAULT_DRAG_ANIMATION_DURATION or DEFAULT_SWIPE_ANIMATION_DURATION depending on the animation type.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView to which the ItemTouchHelper is attached to.

int animationType

The type of animation. Is one of ANIMATION_TYPE_DRAG, ANIMATION_TYPE_SWIPE_CANCEL or ANIMATION_TYPE_SWIPE_SUCCESS.

float animateDx

The horizontal distance that the animation will offset

float animateDy

The vertical distance that the animation will offset

Returns
long

The duration for the animation

getBoundingBoxMargin

Added in 1.0.0
public int getBoundingBoxMargin()

When finding views under a dragged view, by default, ItemTouchHelper searches for views that overlap with the dragged View. By overriding this method, you can extend or shrink the search box.

Returns
int

The extra margin to be added to the hit box of the dragged View.

getDefaultUIUtil

Added in 1.0.0
public static @NonNull ItemTouchUIUtil getDefaultUIUtil()

Returns the ItemTouchUIUtil that is used by the Callback class for visual changes on Views in response to user interactions. ItemTouchUIUtil has different implementations for different platform versions.

By default, Callback applies these changes on itemView.

For example, if you have a use case where you only want the text to move when user swipes over the view, you can do the following:

    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder){
        getDefaultUIUtil().clearView(((ItemTouchViewHolder) viewHolder).textView);
    }
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
        if (viewHolder != null){
            getDefaultUIUtil().onSelected(((ItemTouchViewHolder) viewHolder).textView);
        }
    }
    public void onChildDraw(Canvas c, RecyclerView recyclerView,
            RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState,
            boolean isCurrentlyActive) {
        getDefaultUIUtil().onDraw(c, recyclerView,
                ((ItemTouchViewHolder) viewHolder).textView, dX, dY,
                actionState, isCurrentlyActive);
        return true;
    }
    public void onChildDrawOver(Canvas c, RecyclerView recyclerView,
            RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState,
            boolean isCurrentlyActive) {
        getDefaultUIUtil().onDrawOver(c, recyclerView,
                ((ItemTouchViewHolder) viewHolder).textView, dX, dY,
                actionState, isCurrentlyActive);
        return true;
    }
Returns
@NonNull ItemTouchUIUtil

The ItemTouchUIUtil instance that is used by the Callback

getMoveThreshold

Added in 1.0.0
public float getMoveThreshold(@NonNull RecyclerView.ViewHolder viewHolder)

Returns the fraction that the user should move the View to be considered as it is dragged. After a view is moved this amount, ItemTouchHelper starts checking for Views below it for a possible drop.

Parameters
@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder that is being dragged.

Returns
float

A float value that denotes the fraction of the View size. Default value is .5f .

getMovementFlags

Added in 1.0.0
public abstract int getMovementFlags(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder
)

Should return a composite flag which defines the enabled move directions in each state (idle, swiping, dragging).

Instead of composing this flag manually, you can use makeMovementFlags or makeFlag.

This flag is composed of 3 sets of 8 bits, where first 8 bits are for IDLE state, next 8 bits are for SWIPE state and third 8 bits are for DRAG state. Each 8 bit sections can be constructed by simply OR'ing direction flags defined in ItemTouchHelper.

For example, if you want it to allow swiping LEFT and RIGHT but only allow starting to swipe by swiping RIGHT, you can return:

     makeFlag(ACTION_STATE_IDLE, RIGHT) | makeFlag(ACTION_STATE_SWIPE, LEFT | RIGHT);
This means, allow right movement while IDLE and allow right and left movement while swiping.
Parameters
@NonNull RecyclerView recyclerView

The RecyclerView to which ItemTouchHelper is attached.

@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder for which the movement information is necessary.

Returns
int

flags specifying which movements are allowed on this ViewHolder.

getSwipeEscapeVelocity

Added in 1.0.0
public float getSwipeEscapeVelocity(float defaultValue)

Defines the minimum velocity which will be considered as a swipe action by the user.

You can increase this value to make it harder to swipe or decrease it to make it easier. Keep in mind that ItemTouchHelper also checks the perpendicular velocity and makes sure current direction velocity is larger then the perpendicular one. Otherwise, user's movement is ambiguous. You can change the threshold by overriding getSwipeVelocityThreshold.

The velocity is calculated in pixels per second.

The default framework value is passed as a parameter so that you can modify it with a multiplier.

Parameters
float defaultValue

The default value (in pixels per second) used by the ItemTouchHelper.

Returns
float

The minimum swipe velocity. The default implementation returns the defaultValue parameter.

getSwipeThreshold

Added in 1.0.0
public float getSwipeThreshold(@NonNull RecyclerView.ViewHolder viewHolder)

Returns the fraction that the user should move the View to be considered as swiped. The fraction is calculated with respect to RecyclerView's bounds.

Default value is .5f, which means, to swipe a View, user must move the View at least half of RecyclerView's width or height, depending on the swipe direction.

Parameters
@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder that is being dragged.

Returns
float

A float value that denotes the fraction of the View size. Default value is .5f .

getSwipeVelocityThreshold

Added in 1.0.0
public float getSwipeVelocityThreshold(float defaultValue)

Defines the maximum velocity ItemTouchHelper will ever calculate for pointer movements.

To consider a movement as swipe, ItemTouchHelper requires it to be larger than the perpendicular movement. If both directions reach to the max threshold, none of them will be considered as a swipe because it is usually an indication that user rather tried to scroll then swipe.

The velocity is calculated in pixels per second.

You can customize this behavior by changing this method. If you increase the value, it will be easier for the user to swipe diagonally and if you decrease the value, user will need to make a rather straight finger movement to trigger a swipe.

Parameters
float defaultValue

The default value(in pixels per second) used by the ItemTouchHelper.

Returns
float

The velocity cap for pointer movements. The default implementation returns the defaultValue parameter.

interpolateOutOfBoundsScroll

Added in 1.0.0
public int interpolateOutOfBoundsScroll(
    @NonNull RecyclerView recyclerView,
    int viewSize,
    int viewSizeOutOfBounds,
    int totalSize,
    long msSinceStartScroll
)

Called by the ItemTouchHelper when user is dragging a view out of bounds.

You can override this method to decide how much RecyclerView should scroll in response to this action. Default implementation calculates a value based on the amount of View out of bounds and the time it spent there. The longer user keeps the View out of bounds, the faster the list will scroll. Similarly, the larger portion of the View is out of bounds, the faster the RecyclerView will scroll.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView instance to which ItemTouchHelper is attached to.

int viewSize

The total size of the View in scroll direction, excluding item decorations.

int viewSizeOutOfBounds

The total size of the View that is out of bounds. This value is negative if the View is dragged towards left or top edge.

int totalSize

The total size of RecyclerView in the scroll direction.

long msSinceStartScroll

The time passed since View is kept out of bounds.

Returns
int

The amount that RecyclerView should scroll. Keep in mind that this value will be passed to scrollBy method.

isItemViewSwipeEnabled

Added in 1.0.0
public boolean isItemViewSwipeEnabled()

Returns whether ItemTouchHelper should start a swipe operation if a pointer is swiped over the View.

Default value returns true but you may want to disable this if you want to start swiping on a custom view touch using startSwipe.

Returns
boolean

True if ItemTouchHelper should start swiping an item when user swipes a pointer over the View, false otherwise. Default value is true.

See also
startSwipe

isLongPressDragEnabled

Added in 1.0.0
public boolean isLongPressDragEnabled()

Returns whether ItemTouchHelper should start a drag and drop operation if an item is long pressed.

Default value returns true but you may want to disable this if you want to start dragging on a custom view touch using startDrag.

Returns
boolean

True if ItemTouchHelper should start dragging an item when it is long pressed, false otherwise. Default value is true.

See also
startDrag

makeFlag

Added in 1.0.0
public static int makeFlag(int actionState, int directions)

Shifts the given direction flags to the offset of the given action state.

Parameters
int actionState

The action state you want to get flags in. Should be one of ACTION_STATE_IDLE, ACTION_STATE_SWIPE or ACTION_STATE_DRAG.

int directions

The direction flags. Can be composed from UP, DOWN, RIGHT, LEFTSTART and END.

Returns
int

And integer that represents the given directions in the provided actionState.

makeMovementFlags

Added in 1.0.0
public static int makeMovementFlags(int dragFlags, int swipeFlags)

Convenience method to create movement flags.

For instance, if you want to let your items be drag &dropped vertically and swiped left to be dismissed, you can call this method with: makeMovementFlags(UP | DOWN, LEFT);

Parameters
int dragFlags

The directions in which the item can be dragged.

int swipeFlags

The directions in which the item can be swiped.

Returns
int

Returns an integer composed of the given drag and swipe flags.

onChildDraw

Added in 1.0.0
public void onChildDraw(
    @NonNull Canvas c,
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    float dX,
    float dY,
    int actionState,
    boolean isCurrentlyActive
)

Called by ItemTouchHelper on RecyclerView's onDraw callback.

If you would like to customize how your View's respond to user interactions, this is a good place to override.

Default implementation translates the child by the given dX, dY. ItemTouchHelper also takes care of drawing the child after other children if it is being dragged. This is done using child re-ordering mechanism. On platforms prior to L, this is achieved via getChildDrawingOrder and on L and after, it changes View's elevation value to be greater than all other children.)

Parameters
@NonNull Canvas c

The canvas which RecyclerView is drawing its children

@NonNull RecyclerView recyclerView

The RecyclerView to which ItemTouchHelper is attached to

@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder which is being interacted by the User or it was interacted and simply animating to its original position

float dX

The amount of horizontal displacement caused by user's action

float dY

The amount of vertical displacement caused by user's action

int actionState

The type of interaction on the View. Is either ACTION_STATE_DRAG or ACTION_STATE_SWIPE.

boolean isCurrentlyActive

True if this view is currently being controlled by the user or false it is simply animating back to its original state.

See also
onChildDrawOver

onChildDrawOver

Added in 1.0.0
public void onChildDrawOver(
    @NonNull Canvas c,
    @NonNull RecyclerView recyclerView,
    RecyclerView.ViewHolder viewHolder,
    float dX,
    float dY,
    int actionState,
    boolean isCurrentlyActive
)

Called by ItemTouchHelper on RecyclerView's onDraw callback.

If you would like to customize how your View's respond to user interactions, this is a good place to override.

Default implementation translates the child by the given dX, dY. ItemTouchHelper also takes care of drawing the child after other children if it is being dragged. This is done using child re-ordering mechanism. On platforms prior to L, this is achieved via getChildDrawingOrder and on L and after, it changes View's elevation value to be greater than all other children.)

Parameters
@NonNull Canvas c

The canvas which RecyclerView is drawing its children

@NonNull RecyclerView recyclerView

The RecyclerView to which ItemTouchHelper is attached to

RecyclerView.ViewHolder viewHolder

The ViewHolder which is being interacted by the User or it was interacted and simply animating to its original position

float dX

The amount of horizontal displacement caused by user's action

float dY

The amount of vertical displacement caused by user's action

int actionState

The type of interaction on the View. Is either ACTION_STATE_DRAG or ACTION_STATE_SWIPE.

boolean isCurrentlyActive

True if this view is currently being controlled by the user or false it is simply animating back to its original state.

See also
onChildDrawOver

onMove

Added in 1.0.0
public abstract boolean onMove(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    @NonNull RecyclerView.ViewHolder target
)

Called when ItemTouchHelper wants to move the dragged item from its old position to the new position.

If this method returns true, ItemTouchHelper assumes viewHolder has been moved to the adapter position of target ViewHolder (ViewHolder#getAdapterPositionInRecyclerView()).

If you don't support drag &drop, this method will never be called.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView to which ItemTouchHelper is attached to.

@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder which is being dragged by the user.

@NonNull RecyclerView.ViewHolder target

The ViewHolder over which the currently active item is being dragged.

Returns
boolean

True if the viewHolder has been moved to the adapter position of target.

See also
onMoved

onMoved

Added in 1.0.0
public void onMoved(
    @NonNull RecyclerView recyclerView,
    @NonNull RecyclerView.ViewHolder viewHolder,
    int fromPos,
    @NonNull RecyclerView.ViewHolder target,
    int toPos,
    int x,
    int y
)

Called when onMove returns true.

ItemTouchHelper does not create an extra Bitmap or View while dragging, instead, it modifies the existing View. Because of this reason, it is important that the View is still part of the layout after it is moved. This may not work as intended when swapped Views are close to RecyclerView bounds or there are gaps between them (e.g. other Views which were not eligible for dropping over).

This method is responsible to give necessary hint to the LayoutManager so that it will keep the View in visible area. For example, for LinearLayoutManager, this is as simple as calling scrollToPositionWithOffset. Default implementation calls scrollToPosition if the View's new position is likely to be out of bounds.

It is important to ensure the ViewHolder will stay visible as otherwise, it might be removed by the LayoutManager if the move causes the View to go out of bounds. In that case, drag will end prematurely.

Parameters
@NonNull RecyclerView recyclerView

The RecyclerView controlled by the ItemTouchHelper.

@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder under user's control.

int fromPos

The previous adapter position of the dragged item (before it was moved).

@NonNull RecyclerView.ViewHolder target

The ViewHolder on which the currently active item has been dropped.

int toPos

The new adapter position of the dragged item.

int x

The updated left value of the dragged View after drag translations are applied. This value does not include margins added by RecyclerView.ItemDecorations.

int y

The updated top value of the dragged View after drag translations are applied. This value does not include margins added by RecyclerView.ItemDecorations.

onSelectedChanged

Added in 1.0.0
public void onSelectedChanged(
    @Nullable RecyclerView.ViewHolder viewHolder,
    int actionState
)

Called when the ViewHolder swiped or dragged by the ItemTouchHelper is changed.

If you override this method, you should call super.
Parameters
@Nullable RecyclerView.ViewHolder viewHolder

The new ViewHolder that is being swiped or dragged. Might be null if it is cleared.

int actionState

One of ACTION_STATE_IDLE, ACTION_STATE_SWIPE or ACTION_STATE_DRAG.

See also
clearView

onSwiped

Added in 1.0.0
public abstract void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction)

Called when a ViewHolder is swiped by the user.

If you are returning relative directions (START , END) from the getMovementFlags method, this method will also use relative directions. Otherwise, it will use absolute directions.

If you don't support swiping, this method will never be called.

ItemTouchHelper will keep a reference to the View until it is detached from RecyclerView. As soon as it is detached, ItemTouchHelper will call clearView.

Parameters
@NonNull RecyclerView.ViewHolder viewHolder

The ViewHolder which has been swiped by the user.

int direction

The direction to which the ViewHolder is swiped. It is one of UP, DOWN, LEFT or RIGHT. If your getMovementFlags method returned relative flags instead of LEFT / RIGHT; `direction` will be relative as well. (START or END).