MainActivity.kt

class MainActivity : AppCompatActivity() {

    ...
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        ...
    }

    private fun addRow(currency: Currency) {
        CurrencyRow(this).run row@{
            initRow(currency)
            dragLinearLayout.run {
                addView(this@row)
                setViewDraggable(this@row, this@row)
                scrollableArea.setOnLongClickListener {
                    val indexToRemove = indexOfChild(this@row)
                    addedCurrencies.removeAt(indexToRemove).let {
                        removedCurrencies.push(it)
                    }
                    layoutTransition = LayoutTransition()
                    removeDragView(this@row)
                    layoutTransition = null
                    Snackbar.make(this, R.string.item_removed, Snackbar.LENGTH_SHORT)
                        .setAction(R.string.undo) {
                            layoutTransition = LayoutTransition()
                            addDragView(this@row, this@row, indexToRemove)
                            layoutTransition = null
                            addedCurrencies.add(indexToRemove, removedCurrencies.pop())
                        }.show()
                    true
                }
            }
        }
    }
    ...
}