ItemTouchHelper

public static final int ACTION_STATE_DRAG = 2

A View is currently being dragged.

public static final int ACTION_STATE_IDLE = 0

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.

public static final int ACTION_STATE_SWIPE = 1

A View is currently being swiped.

public static final int ANIMATION_TYPE_DRAG = 8

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

public static final int ANIMATION_TYPE_SWIPE_CANCEL = 4

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

public static final int ANIMATION_TYPE_SWIPE_SUCCESS = 2

Animation type for views which are swiped successfully.

public static final int DOWN = 2

Down direction, used for swipe &drag control.

public static final int END = 32

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

public static final int LEFT = 4

Left direction, used for swipe &drag control.

public static final int RIGHT = 8

Right direction, used for swipe &drag control.

public static final int START = 16

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

public static final int UP = 1

Up direction, used for swipe &drag control.

public ItemTouchHelper(@NonNull ItemTouchHelper.Callback callback)

Creates an ItemTouchHelper that will work with the given Callback.

You can attach ItemTouchHelper to a RecyclerView via attachToRecyclerView. Upon attaching, it will add an item decoration, an onItemTouchListener and a Child attach / detach listener to the RecyclerView.

public void attachToRecyclerView(@Nullable RecyclerView recyclerView)

Attaches the ItemTouchHelper to the provided RecyclerView. If TouchHelper is already attached to a RecyclerView, it will first detach from the previous one. You can call this method with null to detach it from the current RecyclerView.

public void getItemOffsets(
    Rect outRect,
    View view,
    RecyclerView parent,
    RecyclerView.State state
)

Retrieve any offsets for the given item. Each field of outRect specifies the number of pixels that the item view should be inset by, similar to padding or margin. The default implementation sets the bounds of outRect to 0 and returns.

If this ItemDecoration does not affect the positioning of item views, it should set all four fields of outRect (left, top, right, bottom) to zero before returning.

If you need to access Adapter for additional data, you can call getChildAdapterPosition to get the adapter position of the View.

public void onChildViewAttachedToWindow(@NonNull View view)

Called when a view is attached to the RecyclerView.

public void onChildViewDetachedFromWindow(@NonNull View view)

Called when a view is detached from RecyclerView.

public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state)

Draw any appropriate decorations into the Canvas supplied to the RecyclerView. Any content drawn by this method will be drawn before the item views are drawn, and will thus appear underneath the views.

public void onDrawOver(
    @NonNull Canvas c,
    @NonNull RecyclerView parent,
    @NonNull RecyclerView.State state
)

Draw any appropriate decorations into the Canvas supplied to the RecyclerView. Any content drawn by this method will be drawn after the item views are drawn and will thus appear over the views.

public void startDrag(@NonNull RecyclerView.ViewHolder viewHolder)

Starts dragging the provided ViewHolder. By default, ItemTouchHelper starts a drag when a View is long pressed. You can disable that behavior by overriding isLongPressDragEnabled.

For this method to work:

• The provided ViewHolder must be a child of the RecyclerView to which this ItemTouchHelper is attached.
• ItemTouchHelper.Callback must have dragging enabled.
• There must be a previous touch event that was reported to the ItemTouchHelper through RecyclerView's ItemTouchListener mechanism. As long as no other ItemTouchListener grabs previous events, this should work as expected.

    viewHolder.dragButton.setOnTouchListener(new View.OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {
            if (MotionEvent.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
                mItemTouchHelper.startDrag(viewHolder);
            }
            return false;
        }
    });

public void startSwipe(@NonNull RecyclerView.ViewHolder viewHolder)

Starts swiping the provided ViewHolder. By default, ItemTouchHelper starts swiping a View when user swipes their finger (or mouse pointer) over the View. You can disable this behavior by overriding ItemTouchHelper.Callback

For this method to work:

• The provided ViewHolder must be a child of the RecyclerView to which this ItemTouchHelper is attached.
• ItemTouchHelper.Callback must have swiping enabled.
• There must be a previous touch event that was reported to the ItemTouchHelper through RecyclerView's ItemTouchListener mechanism. As long as no other ItemTouchListener grabs previous events, this should work as expected.

    viewHolder.dragButton.setOnTouchListener(new View.OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {
            if (MotionEvent.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
                mItemTouchHelper.startSwipe(viewHolder);
            }
            return false;
        }
    });