StaticListPagingSourceFactory.kt
/*
* Copyright 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.paging.testing
import androidx.paging.InvalidatingPagingSourceFactory
import androidx.paging.PagingSource
import androidx.paging.Pager
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.launch
/**
* Extension method on a [Flow] to generate a `PagingSourceFactory` for constructing a [Pager].
*
* The [Flow] of list represents the data source, with each static list representing a generation
* of data from which a [PagingSource] will load from. With every emission, the current
* [PagingSource] will be invalidated, thereby triggering a new generation of Paged data.
*
* Supports multiple factories and thus multiple collection on the same flow.
*
* Returns a `pagingSourceFactory` to be supplied to a [Pager].
*
* @param coroutineScope the CoroutineScope to collect from the Flow of list.
*/
public fun <Value : Any> Flow<@JvmSuppressWildcards List<Value>>.asPagingSourceFactory(
coroutineScope: CoroutineScope
): () -> PagingSource<Int, Value> {
var data: List<Value>? = null
val factory = InvalidatingPagingSourceFactory {
val dataSource = data ?: emptyList()
@Suppress("UNCHECKED_CAST")
StaticListPagingSource(dataSource)
}
coroutineScope.launch {
collect { list ->
data = list
factory.invalidate()
}
}
return factory
}