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/*
* This file is part of GNU Taler
* (C) 2020 Taler Systems S.A.
*
* GNU Taler is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation; either version 3, or (at your option) any later version.
*
* GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
package net.taler.merchantpos.order
import android.os.Bundle
import android.view.LayoutInflater
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.fragment.app.activityViewModels
import androidx.lifecycle.Observer
import androidx.recyclerview.selection.ItemDetailsLookup
import androidx.recyclerview.selection.ItemKeyProvider
import androidx.recyclerview.selection.SelectionPredicates
import androidx.recyclerview.selection.SelectionTracker
import androidx.recyclerview.selection.StorageStrategy
import androidx.recyclerview.widget.AsyncListDiffer
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.Adapter
import androidx.recyclerview.widget.RecyclerView.ViewHolder
import kotlinx.android.synthetic.main.fragment_order_state.*
import net.taler.common.fadeIn
import net.taler.common.fadeOut
import net.taler.merchantpos.MainViewModel
import net.taler.merchantpos.R
import net.taler.merchantpos.config.ConfigProduct
import net.taler.merchantpos.order.OrderAdapter.OrderLineLookup
import net.taler.merchantpos.order.OrderAdapter.OrderViewHolder
class OrderStateFragment : Fragment() {
private val viewModel: MainViewModel by activityViewModels()
private val orderManager by lazy { viewModel.orderManager }
private val liveOrder by lazy { orderManager.getOrder(orderManager.currentOrderId.value!!) }
private val adapter = OrderAdapter()
private var tracker: SelectionTracker<String>? = null
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(R.layout.fragment_order_state, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
orderList.apply {
adapter = this@OrderStateFragment.adapter
layoutManager = LinearLayoutManager(requireContext())
}
val detailsLookup = OrderLineLookup(orderList)
val tracker = SelectionTracker.Builder(
"order-selection-id",
orderList,
adapter.keyProvider,
detailsLookup,
StorageStrategy.createStringStorage()
).withSelectionPredicate(
SelectionPredicates.createSelectSingleAnything()
).build()
savedInstanceState?.let { tracker.onRestoreInstanceState(it) }
adapter.tracker = tracker
this.tracker = tracker
if (savedInstanceState == null) {
// select last selected order line when re-creating this fragment
// do it before attaching the tracker observer
liveOrder.selectedProductKey?.let { tracker.select(it) }
}
tracker.addObserver(object : SelectionTracker.SelectionObserver<String>() {
override fun onItemStateChanged(key: String, selected: Boolean) {
super.onItemStateChanged(key, selected)
val item = if (selected) adapter.getItemByKey(key) else null
liveOrder.selectOrderLine(item)
}
})
liveOrder.order.observe(viewLifecycleOwner, Observer { order ->
onOrderChanged(order, tracker)
})
liveOrder.orderTotal.observe(viewLifecycleOwner, Observer { orderTotal ->
if (orderTotal == 0.0) {
totalView.fadeOut()
totalView.text = null
} else {
val currency = viewModel.configManager.merchantConfig?.currency
totalView.text = getString(R.string.order_total, orderTotal, currency)
totalView.fadeIn()
}
})
}
override fun onSaveInstanceState(outState: Bundle) {
super.onSaveInstanceState(outState)
tracker?.onSaveInstanceState(outState)
}
private fun onOrderChanged(order: Order, tracker: SelectionTracker<String>) {
adapter.setItems(order.products) {
liveOrder.lastAddedProduct?.let {
val position = adapter.findPosition(it)
if (position >= 0) {
// orderList can be null m(
orderList?.scrollToPosition(position)
orderList?.post { this.tracker?.select(it.id) }
}
}
// workaround for bug: SelectionObserver doesn't update when removing selected item
if (tracker.hasSelection()) {
val key = tracker.selection.first()
val product = order.products.find { it.id == key }
if (product == null) tracker.clearSelection()
}
}
}
}
private class OrderAdapter : Adapter<OrderViewHolder>() {
lateinit var tracker: SelectionTracker<String>
val keyProvider = OrderKeyProvider()
private val itemCallback = object : DiffUtil.ItemCallback<ConfigProduct>() {
override fun areItemsTheSame(oldItem: ConfigProduct, newItem: ConfigProduct): Boolean {
return oldItem == newItem
}
override fun areContentsTheSame(oldItem: ConfigProduct, newItem: ConfigProduct): Boolean {
return oldItem.quantity == newItem.quantity
}
}
private val differ = AsyncListDiffer(this, itemCallback)
override fun getItemCount() = differ.currentList.size
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): OrderViewHolder {
val view =
LayoutInflater.from(parent.context).inflate(R.layout.list_item_order, parent, false)
return OrderViewHolder(view)
}
override fun onBindViewHolder(holder: OrderViewHolder, position: Int) {
val item = getItem(position)!!
holder.bind(item, tracker.isSelected(item.id))
}
fun setItems(items: List<ConfigProduct>, commitCallback: () -> Unit) {
// toMutableList() is needed for some reason, otherwise doesn't update adapter
differ.submitList(items.toMutableList(), commitCallback)
}
fun getItem(position: Int): ConfigProduct? = differ.currentList[position]
fun getItemByKey(key: String): ConfigProduct? {
return differ.currentList.find { it.id == key }
}
fun findPosition(product: ConfigProduct): Int {
return differ.currentList.indexOf(product)
}
private inner class OrderViewHolder(private val v: View) : ViewHolder(v) {
private val quantity: TextView = v.findViewById(R.id.quantity)
private val name: TextView = v.findViewById(R.id.name)
private val price: TextView = v.findViewById(R.id.price)
fun bind(product: ConfigProduct, selected: Boolean) {
v.isActivated = selected
quantity.text = product.quantity.toString()
name.text = product.localizedDescription
price.text = String.format("%.2f", product.priceAsDouble * product.quantity)
}
}
private inner class OrderKeyProvider : ItemKeyProvider<String>(SCOPE_MAPPED) {
override fun getKey(position: Int) = getItem(position)!!.id
override fun getPosition(key: String): Int {
return differ.currentList.indexOfFirst { it.id == key }
}
}
internal class OrderLineLookup(private val list: RecyclerView) : ItemDetailsLookup<String>() {
override fun getItemDetails(e: MotionEvent): ItemDetails<String>? {
list.findChildViewUnder(e.x, e.y)?.let { view ->
val holder = list.getChildViewHolder(view)
val adapter = list.adapter as OrderAdapter
val position = holder.adapterPosition
return object : ItemDetails<String>() {
override fun getPosition(): Int = position
override fun getSelectionKey(): String = adapter.keyProvider.getKey(position)
override fun inSelectionHotspot(e: MotionEvent) = true
}
}
return null
}
}
}
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