BayernMessenger/vector/src/main/java/im/vector/riotx/features/home/room/detail/ScrollOnHighlightedEventCal...

50 lines
2.0 KiB
Kotlin

/*
* Copyright 2019 New Vector Ltd
*
* 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 im.vector.riotx.features.home.room.detail
import androidx.recyclerview.widget.LinearLayoutManager
import im.vector.riotx.core.platform.DefaultListUpdateCallback
import im.vector.riotx.features.home.room.detail.timeline.TimelineEventController
import java.util.concurrent.atomic.AtomicReference
class ScrollOnHighlightedEventCallback(private val layoutManager: LinearLayoutManager,
private val timelineEventController: TimelineEventController) : DefaultListUpdateCallback {
private val scheduledEventId = AtomicReference<String?>()
override fun onChanged(position: Int, count: Int, tag: Any?) {
val eventId = scheduledEventId.get() ?: return
val positionToScroll = timelineEventController.searchPositionOfEvent(eventId)
if (positionToScroll != null) {
val firstVisibleItem = layoutManager.findFirstCompletelyVisibleItemPosition()
val lastVisibleItem = layoutManager.findLastCompletelyVisibleItemPosition()
// Do not scroll it item is already visible
if (positionToScroll !in firstVisibleItem..lastVisibleItem) {
// Note: Offset will be from the bottom, since the layoutManager is reversed
layoutManager.scrollToPosition(position)
}
scheduledEventId.set(null)
}
}
fun scheduleScrollTo(eventId: String?) {
scheduledEventId.set(eventId)
}
}