我试图用分页库制作字典应用程序。
当用户写任何字母时,我将调用API并获取包括该字母在内的所有单词。
问题是,当我通过ViewHolder的init{}
方法中的Paging库调用API时,它可以正常工作。但是之后,当我尝试编写其他内容并获取相关数据时,Paging库甚至不调用API。我在每个位置都放置了断点,并且我第一次看到,DataSource.Factory的create()
方法没有得到调用。
这是我的代码:
我的 Activity :
viewModel = ViewModelProviders.of(this).get(DictionaryViewModel::class.java)
val adapter = DictionaryRecyclerPagedAdapter()
recycler.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)
recycler.setHasFixedSize(true)
recycler.adapter = adapter
RxTextView.textChanges(edtWord)
.filter { it.isNotBlank() }
.subscribe({
adapter.submitList(null)
viewModel.getWord(it.toString())
Logger.d(it)
}, {
Logger.d(it)
})
viewModel.itemPagedList?.observe(this, Observer {
adapter.submitList(it)
})
我的ViewModel:
var liveDataSource: LiveData<PageKeyedDataSource<Int, DictionaryResult>>? = null
var itemPagedList: LiveData<PagedList<DictionaryResult>>? = null
init {
getWord("pouya")
}
fun getWord(term: String) {
val dataSourceFactory = DictionaryDataFactory(term)
liveDataSource = dataSourceFactory.liveData
val config = PagedList.Config.Builder()
.setEnablePlaceholders(true)
.setPageSize(10)
.setPrefetchDistance(4)
.build()
itemPagedList = LivePagedListBuilder(dataSourceFactory, config).build()
}
我的数据源:
class DictionaryDataSource(private val term: String) : PageKeyedDataSource<Int, DictionaryResult>() {
override fun loadInitial(params: LoadInitialParams<Int>, callback: LoadInitialCallback<Int, DictionaryResult>) {
Logger.d("Initial")
composite.add(
repository.getWord(FIRST_PAGE, term)
.subscribe({
if (it.result != null)
callback.onResult(it.result, null, FIRST_PAGE + 1)
}, {
Logger.d(it)
})
)
}
override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Int, DictionaryResult>) {
Logger.d("AFTER")
composite.add(repository.getWord(params.key, term)
.subscribe({
if (it.result != null)
callback.onResult(it.result, params.key + 1)
}, {
Logger.d(it)
})
)
}
}
我的DataSource.Factory:
class DictionaryDataFactory(private val term: String) : DataSource.Factory<Int, DictionaryResult>() {
val liveData = MutableLiveData<PageKeyedDataSource<Int, DictionaryResult>>()
override fun create(): DataSource<Int, DictionaryResult> {
val dataSource = DictionaryDataSource(term)
liveData.postValue(dataSource)
return dataSource
}
}
因此,请记住这一点,它在我启动该应用程序后就可以完美运行(它获得了
"pouya"
一词的所有含义,就像我在ViewHolder的init{}
方法中调用它的意思一样),但是之后,当我在edittext中编写内容时,所有所需的方法会被调用,create()
的DataSource.Factory
方法除外。任何帮助将不胜感激。
最佳答案
我也遇到过同样的问题,为我解决的问题是在设置观察者之前构建列表,在您的情况下,请确保在观察itemPagedList之前调用getWord()
例如 :-
这是使用viewModel.reponseList的片段的片段
override fun onViewReady() {
setRecyclerView()
viewModel.buildResponseList() //For some reason responseList must be built before observing on it ,
// otherwise create() in FoodDataSourceFactory won't be called
setObservers()
}
private fun setObservers() {
viewModel.responseList.observe(this, Observer {
(this.rvFoodList.adapter as FoodListAdapter).submitList(it)
})
}
private fun setRecyclerView() {
val mRecyclerView = this.rvFoodList
mRecyclerView.apply {
layoutManager = LinearLayoutManager(this@HomeFragment.context)
adapter = FoodListAdapter()
}
ViewModel部分:-
fun buildResponseList() {
val foodDataSourceFactory =
FoodDataSourceFactory(this)
val config = PagedList.Config.Builder()
.setInitialLoadSizeHint(30)
.setEnablePlaceholders(false)
.setPageSize(30)
.build()
responseList = LivePagedListBuilder(foodDataSourceFactory, config).build()
}
在onViewReady()中
如果我在调用viewModel.buildResponseList()之前设置了setObservers()
DataSourceFactory类不会调用create()方法,因此不会在DataSource类中进行网络调用