我尝试使用数据绑定实现 Android 分页库。 我无法利用现有的公共资源来实现它。 是否可以将分页库与数据绑定和绑定适配器一起使用？
Github 上的项目： https://github.com/DoomMortal/paging
有人可以调查一下吗？ 任何帮助将不胜感激。
我的适配器：
class OverviewAdapter(val onClickListener: OnClickListener) : PagedListAdapter<VideoProperty, OverviewAdapter.ViewHolder>(DiffCallback) {
class ViewHolder private constructor(private var binding: OverviewItemBinding) : RecyclerView.ViewHolder(binding.root) {
fun bind(clickListener: OnClickListener, videoProperty: VideoProperty){
binding.property = videoProperty
binding.clickListener = clickListener
binding.executePendingBindings()
}
companion object {
fun from(parent: ViewGroup): ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = OverviewItemBinding.inflate(layoutInflater, parent, false)
return ViewHolder(binding)
}
}
}
companion object DiffCallback : DiffUtil.ItemCallback<VideoProperty>() {
override fun areItemsTheSame(oldItem: VideoProperty, newItem: VideoProperty): Boolean {
return oldItem === newItem
}
override fun areContentsTheSame(oldItem: VideoProperty, newItem: VideoProperty): Boolean {
return oldItem.videoTableId == newItem.videoTableId
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder.from(parent)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
when (holder) {
is ViewHolder -> {
val nightItem = getItem(position) as VideoProperty
holder.bind(onClickListener, nightItem)
}
}
}
class OnClickListener(val clicklistener: (videoProperty: VideoProperty) -> Unit) {
fun onClick(videoProperty: VideoProperty) = clicklistener(videoProperty)
}
}
视图模型：
enum class MarsApiStatus { LOADING, ERROR, DONE }
class OverviewViewModel : ViewModel() {
private val TAG = "OverviewViewModel"
private var executor: Executor? = null
// The internal MutableLiveData String that stores the status of the most recent request
private val _status = MutableLiveData<MarsApiStatus>()
// The external immutable LiveData for the request status String
val status: LiveData<MarsApiStatus>
get() = _status
private val _properties = MutableLiveData<VideosOverview>()
val properties: LiveData<VideosOverview>
get() = _properties
private val _navigateToSelectedProperty = MutableLiveData<VideoProperty>()
val navigateToSelectedProperty: LiveData<VideoProperty>
get() = _navigateToSelectedProperty
private var viewModelJob = Job()
private val coroutineScope = CoroutineScope(viewModelJob + Dispatchers.Main)
//val itemPagedList: LiveData<PagedList<VideosOverview>>
var itemPagedList: LiveData<PagedList<VideosOverview>>
var liveDataSource: LiveData<PageKeyedDataSource<Int, VideosOverview>>? = null
/**
* Call getMarsRealEstateProperties() on init so we can display status immediately.
*/
init {
//getMarsRealEstateProperties(VideosOverviewApiFilter.SHOW_POOP)
executor = Executors.newFixedThreadPool(5)
val feedDataFactory = ItemDataSourceFactory()
val pagedListConfig = PagedList.Config.Builder()
.setEnablePlaceholders(false)
.setPageSize(ItemVideosDataSource.PAGE_SIZE)
.build()
/*_properties.value = LivePagedListBuilder(feedDataFactory, pagedListConfig)
.build()*/
liveDataSource = feedDataFactory.getItemLiveDataSource()
itemPagedList = LivePagedListBuilder(feedDataFactory, pagedListConfig).build()
}
/**
* Sets the value of the status LiveData to the VideosOverview API status.
*/
private fun getMarsRealEstateProperties(filter: VideosOverviewApiFilter, page: Long) {
coroutineScope.launch {
//val getPropertiesDeferred =
try{
_status.value = MarsApiStatus.LOADING
val listResult = VideosOverviewApi.retrofitService.getProperties(filter.value, page)
Log.d("CONTENT: ", filter.value.toString())
Log.d("CONTENT: ", page.toString())
Log.d("CONTENT: ", listResult.items[0].toString())
_status.value = MarsApiStatus.DONE
if (listResult.items.size > 0) {
_properties.value = listResult
}
} catch (e: Throwable){
Log.d(TAG, e.toString())
_status.value = MarsApiStatus.ERROR
//_properties.value = ArrayList() OLD
}
}
}
override fun onCleared() {
super.onCleared()
viewModelJob.cancel()
}
fun displayPropertyDetails(marsProperty: VideoProperty) {
_navigateToSelectedProperty.value = marsProperty
}
fun displayPropertyDetailsComplete() {
_navigateToSelectedProperty.value = null
}
fun updateFilter(filter: VideosOverviewApiFilter, page: Long){
getMarsRealEstateProperties(filter, page)
}
}
数据来源：
class ItemVideosDataSource : PageKeyedDataSource<Long, VideosOverview>() {
companion object {
val FIRST_PAGE: Long = 1
val PAGE_SIZE: Int = 50
}
private val TAG = "ItemVideosDataSource"
private var viewModelJob = Job()
private val coroutineScope = CoroutineScope(viewModelJob + Dispatchers.Main)
override fun loadInitial(params: LoadInitialParams<Long>, callback: LoadInitialCallback<Long, VideosOverview>) {
//videos.retrofitService.getProperties(FIRST_PAGE)
coroutineScope.launch {
//val getPropertiesDeferred =
try{
val listResult = VideosOverviewApi.retrofitService.getProperties(1, FIRST_PAGE)
val lest : MutableList<VideosOverview>? = null
lest!!.add(listResult)
if (listResult.items.size > 0) {
callback.onResult(lest, null, FIRST_PAGE + 1)
//_properties.value = listResult
}
} catch (e: Throwable){
Log.d(TAG, e.toString())
}
}
}
override fun loadBefore(params: LoadParams<Long>, callback: LoadCallback<Long, VideosOverview>) {
coroutineScope.launch {
//val getPropertiesDeferred =
try{
val listResult = VideosOverviewApi.retrofitService.getProperties(1, FIRST_PAGE)
val lest : MutableList<VideosOverview>? = null
lest!!.add(listResult)
if (listResult.items.size > 0) {
val key: Long? = if(params.key > 1) params.key - 1 else null
callback.onResult(lest, key)
//_properties.value = listResult
}
} catch (e: Throwable){
Log.d(TAG, e.toString())
}
}
}
override fun loadAfter(params: LoadParams<Long>, callback: LoadCallback<Long, VideosOverview>) {
coroutineScope.launch {
//val getPropertiesDeferred =
try{
val listResult = VideosOverviewApi.retrofitService.getProperties(1, FIRST_PAGE)
val lest : MutableList<VideosOverview>? = null
lest!!.add(listResult)
if (listResult.items.size > 0) {
val key: Long? = if(params.key > 1) params.key + 1 else null
callback.onResult(lest, key)
//_properties.value = listResult
}
} catch (e: Throwable){
Log.d(TAG, e.toString())
}
}
}
}
工厂方法：
class ItemDataSourceFactory : DataSource.Factory<Long, VideosOverview>() {
//val sourceLiveData = MutableLiveData<ItemVideosDataSource>()
private val itemLiveDataSource = MutableLiveData<PageKeyedDataSource<Int, VideosOverview>>()
override fun create(): DataSource<Long, VideosOverview> {
//getting our data source object
val itemDataSource = ItemVideosDataSource()
//posting the datasource to get the values
//itemLiveDataSource.postValue(itemDataSource)
//returning the datasource
return itemDataSource
}
fun getItemLiveDataSource(): MutableLiveData<PageKeyedDataSource<Int, VideosOverview>> {
return itemLiveDataSource
}
}
布局：
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_overview"
android:layout_width="0dp"
android:layout_height="0dp"
android:clipToPadding="false"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
app:listData="@{viewModel.itemPagedList}"
tools:listitem="@layout/overview_item" />
绑定适配器
@BindingAdapter("listData")
fun bindRecyclerView(recyclerView: RecyclerView, data: PagedList<VideoProperty>?){
//fun bindRecyclerView(recyclerView: RecyclerView, data: List<VideoProperty>?){
val adapter = recyclerView.adapter as OverviewAdapter
adapter.submitList(data)
}
以防万一有另一种解决方案，我使用了这个示例并工作
https://github.com/sharmadhiraj/AndroidPagingLibraryStepByStepImplementationGuide