/
HideBottomViewOnScrollBehaviorScrollStateChanges.kt
137 lines (128 loc) · 4.64 KB
/
HideBottomViewOnScrollBehaviorScrollStateChanges.kt
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/*
* Copyright 2022 Vladimir Raupov
*
* 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 ru.ldralighieri.corbind.material
import android.view.View
import androidx.annotation.CheckResult
import androidx.coordinatorlayout.widget.CoordinatorLayout
import com.google.android.material.behavior.HideBottomViewOnScrollBehavior
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.channels.ReceiveChannel
import kotlinx.coroutines.channels.actor
import kotlinx.coroutines.channels.awaitClose
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.channelFlow
import kotlinx.coroutines.isActive
import ru.ldralighieri.corbind.internal.corbindReceiveChannel
/**
* Perform an action on the bottom view scroll state change events from [View] on
* [HideBottomViewOnScrollBehavior].
*
* @param scope Root coroutine scope
* @param capacity Capacity of the channel's buffer (no buffer by default)
* @param action An action to perform
*/
fun View.bottomViewScrollStateChanges(
scope: CoroutineScope,
capacity: Int = Channel.RENDEZVOUS,
action: suspend (Int) -> Unit,
) {
val events = scope.actor<Int>(Dispatchers.Main.immediate, capacity) {
for (state in channel) action(state)
}
val behavior = getBehavior()
val listener = listener(scope, events::trySend)
behavior.addOnScrollStateChangedListener(listener)
events.invokeOnClose { behavior.removeOnScrollStateChangedListener(listener) }
}
/**
* Perform an action on the bottom view scroll state change events from [View] on
* [HideBottomViewOnScrollBehavior], inside new [CoroutineScope].
*
* @param capacity Capacity of the channel's buffer (no buffer by default)
* @param action An action to perform
*/
suspend fun View.bottomViewScrollStateChanges(
capacity: Int = Channel.RENDEZVOUS,
action: suspend (Int) -> Unit,
) = coroutineScope {
bottomViewScrollStateChanges(this, capacity, action)
}
/**
* Create a channel which emits the bottom view scroll state change events from [View] on
* [HideBottomViewOnScrollBehavior].
*
* *Note:* A value will be emitted immediately.
*
* Examples:
*
* ```
* launch {
* bottomView.bottomViewScrollStateChanges(scope)
* .consumeEach { /* handle bottom view scroll state change */ }
* }
* ```
*
* @param scope Root coroutine scope
* @param capacity Capacity of the channel's buffer (no buffer by default)
*/
@CheckResult
fun View.bottomViewScrollStateChanges(
scope: CoroutineScope,
capacity: Int = Channel.RENDEZVOUS,
): ReceiveChannel<Int> = corbindReceiveChannel(capacity) {
val behavior = getBehavior()
val listener = listener(scope, ::trySend)
behavior.addOnScrollStateChangedListener(listener)
invokeOnClose { behavior.removeOnScrollStateChangedListener(listener) }
}
/**
* Create a flow which emits the bottom view scroll state change events from [View] on
* [HideBottomViewOnScrollBehavior].
*
* *Note:* A value will be emitted immediately.
*
* Examples:
*
* ```
* bottomView.bottomViewScrollStateChanges()
* .onEach { /* handle bottom view scroll state change */ }
* .flowWithLifecycle(lifecycle)
* .launchIn(lifecycleScope) // lifecycle-runtime-ktx
* ```
*/
@CheckResult
fun View.bottomViewScrollStateChanges(): Flow<Int> = channelFlow {
val behavior = getBehavior()
val listener = listener(this, ::trySend)
behavior.addOnScrollStateChangedListener(listener)
awaitClose { behavior.removeOnScrollStateChangedListener(listener) }
}
private fun View.getBehavior(): HideBottomViewOnScrollBehavior<*> {
val params = layoutParams as? CoordinatorLayout.LayoutParams
?: throw IllegalArgumentException("The view is not in a Coordinator Layout.")
return params.behavior as HideBottomViewOnScrollBehavior<*>?
?: throw IllegalStateException("There's no HideBottomViewOnScrollBehavior set on this view.")
}
@CheckResult
private fun listener(
scope: CoroutineScope,
emitter: (Int) -> Unit,
) = HideBottomViewOnScrollBehavior.OnScrollStateChangedListener { _, newState ->
if (scope.isActive) emitter(newState)
}