FlowAdapter.kt
/*
* Copyright 2020 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.compose.runtime
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.withContext
import kotlin.coroutines.CoroutineContext
import kotlin.coroutines.EmptyCoroutineContext
/**
* Collects values from this [StateFlow] and represents its latest value via [State].
* The [StateFlow.value] is used as an initial value. Every time there would be new value posted
* into the [StateFlow] the returned [State] will be updated causing recomposition of every
* [State.value] usage.
*
* @sample androidx.compose.runtime.samples.StateFlowSample
*
* @param context [CoroutineContext] to use for collecting.
*/
@ExperimentalCoroutinesApi
@Composable
fun <T> StateFlow<T>.collectAsState(
context: CoroutineContext = EmptyCoroutineContext
): State<T> = collectAsState(value, context)
/**
* Collects values from this [Flow] and represents its latest value via [State]. Every time there
* would be new value posted into the [Flow] the returned [State] will be updated causing
* recomposition of every [State.value] usage.
*
* @sample androidx.compose.runtime.samples.FlowWithInitialSample
*
* @param context [CoroutineContext] to use for collecting.
*/
@Composable
fun <T : R, R> Flow<T>.collectAsState(
initial: R,
context: CoroutineContext = EmptyCoroutineContext
): State<R> = produceState(initial, this, context) {
if (context == EmptyCoroutineContext) {
collect { value = it }
} else withContext(context) {
collect { value = it }
}
}