所以我有一个奇怪的行为,我的 RecyclerView
只在我启动应用程序时显示数据,然后通过 Android Studio 重新启动活动。或者在 XML 中进行更改,然后撤消它并重新启动。
然后显示的数据是正确的,当我添加东西时也会更新,但在启动应用程序后它不可见。
谁能帮帮我?我真的不知道为什么会这样。
片段:
@AndroidEntryPoint
class HistoryFragment : Fragment(R.layout.fragment_history) {
private val viewModel: PurchaseViewmodel by viewModels()
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val binding = FragmentHistoryBinding.bind(view)
val exampleAdapter = ExampleAdapter()
binding.apply{
recyclerView.apply{
layoutManager = LinearLayoutManager(requireContext())
adapter = exampleAdapter
setHasFixedSize(true)
}
ItemTouchHelper(object : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT) {
override fun onMove(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder,
target: RecyclerView.ViewHolder
): Boolean {
return false /// We dont need any interaction with Drag&Drop we only want swipe left&right
}
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
val receipt = exampleAdapter.currentList[viewHolder.adapterPosition]
viewModel.onSwipe(receipt)
}
}).attachToRecyclerView(recyclerView)
}
setFragmentResultListener("add_receipt_request"){_,bundle ->
val result = bundle.getInt("add_receipt_request")
viewModel.onAddResult(result)
}
viewModel.receipts.observe(viewLifecycleOwner){ /// New Items get passed to the List
exampleAdapter.submitList(it)
}
viewLifecycleOwner.lifecycleScope.launchWhenStarted { //as soon as we close our app the events will be suspended, but not deleted and will remain after restart
viewModel.addTaskEvent.collect { event->
when(event){
is PurchaseViewmodel.TasksEvent.ShowUndoDelete -> {
Snackbar.make(requireView(),"Tasks deleted", Snackbar.LENGTH_LONG)
.setAction("UNDO"){
viewModel.unDoDeleteClick(event.receipts)
}.show()
}
}
}
}
}
}
适配器:
class ExampleAdapter : ListAdapter<Receipts,ExampleAdapter.ExampleViewHolder>(DiffCallback()) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ExampleViewHolder {
val binding = ReceiptsBinding.inflate(LayoutInflater.from(parent.context),parent,false)
return ExampleViewHolder(binding)
}
override fun onBindViewHolder(holder: ExampleViewHolder, position: Int) {
val currentItem = getItem(position)
holder.bind(currentItem)
}
override fun getItemCount(): Int {
return super.getItemCount()
}
class ExampleViewHolder(private val binding: ReceiptsBinding) : RecyclerView.ViewHolder(binding.root){ //Examples One Row in our list
fun bind (receipts: Receipts) {
binding.apply {
storeHistory.text = receipts.store
amountHistory.text = receipts.total
dateHistory.text = receipts.date
}
}
}
class DiffCallback : DiffUtil.ItemCallback<Receipts>() {
override fun areItemsTheSame(oldItem: Receipts, newItem: Receipts) =
oldItem.id == newItem.id
override fun areContentsTheSame(oldItem: Receipts, newItem: Receipts) =
oldItem == newItem
}
}
答案 0 :(得分:0)
您应该比较 Receipts
中旧/新 areContentsTheSame()
的对应字段,而不是比较整个旧/新对象
override fun areContentsTheSame(oldItem: Receipts, newItem: Receipts) =
oldItem.store == newItem.store
&& oldItem.total == newItem.total
&& oldItem.date == newItem.date