Custom CalendarDataSource

app/src/main/java/com/battlelancer/seriesguide/ui/shows/CalendarAdapter2.kt

@@ -37,7 +37,7 @@ class CalendarAdapter2(
 
     override fun getItemViewType(position: Int): Int {
         val item = getItem(position)
-        val isHeader = item != null && item.episode == null
+        val isHeader = item.episode == null
         return if (isHeader) {
             VIEW_TYPE_HEADER
         } else {
@@ -55,11 +55,11 @@ class CalendarAdapter2(
 
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
         val currentItem = getItem(position)
-        val previousPosition = position - 1
-        val previousItem = if (previousPosition >= 0) getItem(previousPosition) else null
+//        val previousPosition = position - 1
+//        val previousItem = if (previousPosition >= 0) getItem(previousPosition) else null
         when (holder) {
             is CalendarHeaderViewHolder -> holder.bind(context, currentItem)
-            is CalendarItemViewHolder -> holder.bind(context, currentItem, previousItem)
+            is CalendarItemViewHolder -> holder.bind(context, currentItem, null)
             else -> throw IllegalArgumentException("Unknown view holder type")
         }
     }

app/src/main/java/com/battlelancer/seriesguide/ui/shows/CalendarDataSource.kt

@@ -0,0 +1,107 @@
+package com.battlelancer.seriesguide.ui.shows
+
+import android.content.Context
+import androidx.paging.PositionalDataSource
+import com.battlelancer.seriesguide.model.EpisodeWithShow
+import com.battlelancer.seriesguide.ui.shows.CalendarFragment2ViewModel.CalendarItem
+import com.battlelancer.seriesguide.util.TimeTools
+import java.util.Calendar
+import java.util.LinkedList
+
+class CalendarDataSource(
+    private val context: Context,
+    private val source: PositionalDataSource<EpisodeWithShow>
+) : PositionalDataSource<CalendarItem>() {
+
+    override fun addInvalidatedCallback(onInvalidatedCallback: InvalidatedCallback) {
+        source.addInvalidatedCallback(onInvalidatedCallback)
+    }
+
+    override fun removeInvalidatedCallback(onInvalidatedCallback: InvalidatedCallback) {
+        source.removeInvalidatedCallback(onInvalidatedCallback)
+    }
+
+    override fun invalidate() {
+        source.invalidate()
+    }
+
+    override fun isInvalid(): Boolean {
+        return source.isInvalid
+    }
+
+    override fun loadInitial(
+        params: LoadInitialParams,
+        callback: LoadInitialCallback<CalendarItem>
+    ) {
+        source.loadInitial(
+            params,
+            object : PositionalDataSource.LoadInitialCallback<EpisodeWithShow>() {
+                override fun onResult(data: List<EpisodeWithShow>, position: Int, totalCount: Int) {
+                    // not using placeholders, can not know the number of headers in advance
+                    callback.onResult(convert(data), position)
+                }
+
+                override fun onResult(data: List<EpisodeWithShow>, position: Int) {
+                    throw IllegalStateException("onResult called by delegate data source.")
+                }
+            })
+    }
+
+    override fun loadRange(params: LoadRangeParams, callback: LoadRangeCallback<CalendarItem>) {
+        // TODO reduce params.startPosition by amount of previously added headers?
+        source.loadRange(
+            params,
+            object : PositionalDataSource.LoadRangeCallback<EpisodeWithShow>() {
+                override fun onResult(data: List<EpisodeWithShow>) {
+                    val converted = convert(data)
+                    if (converted.size > params.loadSize) {
+                        val cutData = LinkedList<CalendarItem>()
+                        for (i in 0 until params.loadSize) {
+                            cutData.add(converted[i])
+                        }
+                        callback.onResult(cutData)
+                    } else {
+                        callback.onResult(converted)
+                    }
+                }
+            })
+    }
+
+    // TODO would also need item before this list if not at position 0
+    private fun convert(episodes: List<EpisodeWithShow>): MutableList<CalendarItem> {
+        val mapped = LinkedList<CalendarItem>()
+
+        val calendar = Calendar.getInstance()
+        var previousHeaderTime: Long = 0
+        episodes.forEachIndexed { index, episode ->
+            // insert header if first item or previous item has different header time
+            val headerTime = calculateHeaderTime(
+                context,
+                calendar,
+                episode.episode_firstairedms
+            )
+            if (index == 0 || headerTime != previousHeaderTime) {
+                mapped.add(CalendarItem(headerTime, null))
+            }
+            previousHeaderTime = headerTime
+
+            mapped.add(CalendarItem(headerTime, episode))
+        }
+
+        return mapped
+    }
+
+    private fun calculateHeaderTime(context: Context, calendar: Calendar, releaseTime: Long): Long {
+        val actualRelease = TimeTools.applyUserOffset(context, releaseTime)
+
+        calendar.time = actualRelease
+        // not midnight because upcoming->recent is delayed 1 hour
+        // so header would display wrong relative time close to midnight
+        calendar.set(Calendar.HOUR_OF_DAY, 1)
+        calendar.set(Calendar.MINUTE, 0)
+        calendar.set(Calendar.SECOND, 0)
+        calendar.set(Calendar.MILLISECOND, 0)
+
+        return calendar.timeInMillis
+    }
+}

app/src/main/java/com/battlelancer/seriesguide/ui/shows/CalendarFragment2ViewModel.kt

@@ -8,7 +8,9 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.Transformations
 import androidx.paging.Config
+import androidx.paging.DataSource
 import androidx.paging.PagedList
+import androidx.paging.PositionalDataSource
 import androidx.paging.toLiveData
 import androidx.sqlite.db.SimpleSQLiteQuery
 import com.battlelancer.seriesguide.model.EpisodeWithShow
@@ -24,25 +26,26 @@ class CalendarFragment2ViewModel(application: Application) : AndroidViewModel(ap
     val upcomingEpisodesLiveData: LiveData<PagedList<CalendarItem>>
 
     private val calendarItemPagingConfig = Config(
-        pageSize = 50,
+        pageSize = 10,
         enablePlaceholders = false /* some items may have a header, so their height differs */
     )
 
     init {
         upcomingEpisodesLiveData = Transformations.switchMap(queryLiveData) { queryString ->
-            SgRoomDatabase.getInstance(getApplication()).episodeHelper()
-                .getEpisodesWithShow(SimpleSQLiteQuery(queryString, null))
-                .mapByPage { episodes ->
-                    val calendar = Calendar.getInstance()
-                    episodes.map { episode ->
-                        val headerTime = calculateHeaderTime(
-                            getApplication(),
-                            calendar,
-                            episode.episode_firstairedms
-                        )
-                        CalendarItem(headerTime, episode)
-                    }
-                }.toLiveData(config = calendarItemPagingConfig)
+            object : DataSource.Factory<Int, CalendarItem>() {
+                override fun create(): DataSource<Int, CalendarItem> {
+                    return CalendarDataSource(
+                        getApplication(),
+                        SgRoomDatabase.getInstance(getApplication()).episodeHelper()
+                            .getEpisodesWithShow(
+                                SimpleSQLiteQuery(
+                                    queryString,
+                                    null
+                                )
+                            ).create() as PositionalDataSource<EpisodeWithShow>
+                    )
+                }
+            }.toLiveData(config = calendarItemPagingConfig)
         }
     }
 

app/src/main/java/com/battlelancer/seriesguide/ui/shows/CalendarItemViewHolder.kt

@@ -16,7 +16,6 @@ import com.battlelancer.seriesguide.util.TextTools
 import com.battlelancer.seriesguide.util.TimeTools
 import com.battlelancer.seriesguide.widgets.WatchedBox
 import com.uwetrottmann.androidutils.CheatSheet
-import java.util.Date
 
 class CalendarItemViewHolder(
     parent: ViewGroup,
@@ -73,14 +72,15 @@ class CalendarItemViewHolder(
         this.item = item
 
         // optional header
-        val isShowingHeader = previousItem == null || previousItem.headerTime != item.headerTime
-        headerTextView.isGone = !isShowingHeader
-        headerTextView.text = if (isShowingHeader) {
-            // display headers like "Mon in 3 days", also "today" when applicable
-            TimeTools.formatToLocalDayAndRelativeWeek(context, Date(item.headerTime))
-        } else {
-            null
-        }
+        headerTextView.isGone = true
+//        val isShowingHeader = previousItem == null || previousItem.headerTime != item.headerTime
+//        headerTextView.isGone = !isShowingHeader
+//        headerTextView.text = if (isShowingHeader) {
+//            // display headers like "Mon in 3 days", also "today" when applicable
+//            TimeTools.formatToLocalDayAndRelativeWeek(context, Date(item.headerTime))
+//        } else {
+//            null
+//        }
 
         val episode = item.episode!!