Update list items in PagingLibrary w/o using Room (Network only)

Question

I\'m using Paging Library to load data from network using ItemKeyedDataSource. After fetching items user can edit them, this updates are done i

Answer 1

All you need to do is to invalidate current DataSource each time you update your data.

What I would do:

• move networking logic from MentionKeyedDataSource to new class that extends PagedList.BoundaryCallback and set it when building your PagedList.

• move all you data to some DataProvider that holds all your downloaded data and has reference to DataSource. Each time data is updated in DataProvider invalidate current DataSource

Something like that maybe

    val dataProvider = PagedDataProvider()
    val dataSourceFactory = InMemoryDataSourceFactory(dataProvider = dataProvider)

where

class PagedDataProvider : DataProvider<Int, DataRow> {

    private val dataCache = mutableMapOf<Int, List<DataRow>>()
    override val sourceLiveData = MutableLiveData<DataSource<Int, DataRow>>()

    //implement data add/remove/update here
    //and after each modification call
    //sourceLiveData.value?.invalidate()
}

and

class InMemoryDataSourceFactory<Key, Value>(
    private val dataProvider: DataProvider<Key, Value>
) : DataSource.Factory<Key, Value>() {

    override fun create(): DataSource<Key, Value> {
        val source = InMemoryDataSource(dataProvider = dataProvider)
        dataProvider.sourceLiveData.postValue(source)
        return source
    }
}

This approach is very similar to what Room does - every time table row is updated - current DataSource is invalidated and DataSourceFactory creates new data source.

Answer 2

You can modify directly in your adapter if you called currentList like that

class ItemsAdapter(): PagedListAdapter<Item, ItemsAdapter.ViewHolder(ITEMS_COMPARATOR) {
    ...
    fun changeItem(position: Int,newData:String) {
        currentList?.get(position)?.data = newData
        notifyItemChanged(position)
    }
   
}