Draggable Recyclerview in KOTLIN

User can easily arrange list items or priorities by drag and drop.

Hello Readers,

How user will feel if he/she can arrange items by just touching finger.

Obviously good!! So lets get started with code.

I am using same code base from my last post. Please check this post here

Recyclerview in KOTLIN

Hopefully you checked the code, in addition we need one adapter to handle drag and drop funtionality.

1- First add ItemTouchHelper to your recyclerview add below code to in your activity file.

val manager  = LinearLayoutManager(this)
rv_name.layoutManager = manager
val itemAdapter = NameAdapter(getNameList(), this)
rv_name.adapter = itemAdapter

val dividerItemDecoration = DividerItemDecoration(this , manager.orientation)
rv_name.addItemDecoration(dividerItemDecoration)


// Setup ItemTouchHelper
val callback = DragManageAdapter(itemAdapter, this,
        ItemTouchHelper.UP.or(ItemTouchHelper.DOWN), ItemTouchHelper.LEFT.or(ItemTouchHelper.RIGHT))
val helper = ItemTouchHelper(callback)
helper.attachToRecyclerView(rv_name)

2-Create a file name DragManageAdapter

class DragManageAdapter(adapter: NameAdapter, context: Context, dragDirs: Int, swipeDirs: Int) : SimpleCallback(dragDirs, swipeDirs)
{
    var nameAdapter = adapter

    override fun onMove(recyclerView: RecyclerView?, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean
    {
        nameAdapter.swapItems(viewHolder.adapterPosition, target.adapterPosition)
        return true
    }

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder?, direction: Int)
    {
    }

}

3- Add this function in NameAdapter file

/**
 * Function called to swap dragged items
 */
fun swapItems(fromPosition: Int, toPosition: Int) {
    if (fromPosition < toPosition) {
        for (i in fromPosition..toPosition - 1) {
            nameList.set(i, nameList.set(i+1, nameList.get(i)));
        }
    } else {
        for (i in fromPosition..toPosition + 1) {
            nameList.set(i, nameList.set(i-1, nameList.get(i)));
        }
    }

    notifyItemMoved(fromPosition, toPosition)
}

Now run your code and see the output. See below

Draggable Recyclerview

Thanks!!