androidandroid-recyclerviewitemtouchhelper

How to make the RecyclerView's ItemTouchHelper work on only part of the list(drag & drop)


I use RecyclerView's ItemTouchHelper to change the order(drag & drop),And I want to move only a part of the list. I don't want to move after a certain index. How can I handle it with one RecyclerView?

If I explain a little more about what I want to make, The active items are sorted up and the non-active items are sorted down. And only the activated items will shift the order. Right now, when I drag an active item, it goes down to the area of ​​the non-active item, but I want to prevent it from going down. How can I do it?

UPDATE

open class SimpleItemTouchHelperCallback(private val mAdapter: ItemTouchHelperAdapter) :
    ItemTouchHelper.Callback() {

    private var isLongPressDrag = true

    fun setLongPressDragEnable(isLongPressDrag: Boolean) {
        this.isLongPressDrag = isLongPressDrag
    }

    override fun isLongPressDragEnabled() = isLongPressDrag

    override fun getMovementFlags(
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder
    ): Int {
        val dragFlags = ItemTouchHelper.UP or ItemTouchHelper.DOWN
        val swipeFlags = 0
        return makeMovementFlags(dragFlags, swipeFlags)
    }

    override fun onMove(
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder,
        target: RecyclerView.ViewHolder
    ): Boolean {
        return mAdapter.onItemMove(viewHolder.adapterPosition, target.adapterPosition)
    }

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, i: Int) {
        mAdapter.onItemDismiss(viewHolder.adapterPosition)
    }

}

Solution

  • Use ItemTouchHelper.SimpleCallback and override getDragDirs and onMove methods:

    ItemTouchHelper.SimpleCallback(
            UP or DOWN,
            0
    ) {
        override fun getDragDirs(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
            val selectedPosition = viewHolder.adapterPosition
            val isActive: Boolean = // retrieve your model from list and check its active state
            return if (isActive) super.getDragDirs(recyclerView, viewHolder) else 0
        }
        override fun onMove(
                recyclerView: RecyclerView,
                viewHolder: RecyclerView.ViewHolder,
                target: RecyclerView.ViewHolder,
        ): Boolean {
            val toPosition = target.adapterPosition
            val isActiveTarget: Boolean = // retrieve your target model from list and check its active state
            if (!isActiveTarget) return false
            val fromPosition = viewHolder.adapterPosition
            moveItem(fromPosition, toPosition)
            return true
        }
    }
    

    Returning 0 on getDragDirs prevents inactive item selection, while returning false on onMove prevents item movement while dragging.