ItemTouchHelper

const val ACTION_STATE_DRAG = 2: Int

A View is currently being dragged.

const val ACTION_STATE_IDLE = 0: Int

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.

const val ACTION_STATE_SWIPE = 1: Int

A View is currently being swiped.

const val ANIMATION_TYPE_DRAG = 8: Int

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

const val ANIMATION_TYPE_SWIPE_CANCEL = 4: Int

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

const val ANIMATION_TYPE_SWIPE_SUCCESS = 2: Int

Animation type for views which are swiped successfully.

const val DOWN = 2: Int

Down direction, used for swipe &drag control.

const val END = 32: Int

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

const val LEFT = 4: Int

Left direction, used for swipe &drag control.

const val RIGHT = 8: Int

Right direction, used for swipe &drag control.

const val START = 16: Int

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

const val UP = 1: Int

Up direction, used for swipe &drag control.

ItemTouchHelper(callback: ItemTouchHelper.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.

fun attachToRecyclerView(recyclerView: RecyclerView?): Unit

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.

fun getItemOffsets(
    outRect: Rect!,
    view: View!,
    parent: RecyclerView!,
    state: RecyclerView.State!
): Unit

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.

fun onChildViewAttachedToWindow(view: View): Unit

Called when a view is attached to the RecyclerView.

fun onChildViewDetachedFromWindow(view: View): Unit

Called when a view is detached from RecyclerView.

fun onDraw(c: Canvas!, parent: RecyclerView!, state: RecyclerView.State!): Unit

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.

fun onDrawOver(c: Canvas, parent: RecyclerView, state: RecyclerView.State): Unit

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.

fun startDrag(viewHolder: RecyclerView.ViewHolder): Unit

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;
        }
    });

fun startSwipe(viewHolder: RecyclerView.ViewHolder): Unit

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;
        }
    });