Use pre-caching feature of DefaultPreloadManager in demo-shortform app

PiperOrigin-RevId: 786250445

Author: tianyif

RELEASENOTES.md

@@ -30,6 +30,8 @@
         `DefaultPreloadManager.PreloadStatus.specifiedRangeCached(durationMs)`
         via `TargetPreloadStatusControl.getTargetPreloadStatus(T rankingData)`
         to indicate that a media item needs to be pre-cached.
+    *   Use pre-caching functionality of `DefaultPreloadManager` in shortform
+        demo app.
 *   Transformer:
 *   Track Selection:
     *   Add `TrackSelectionParameters.selectTextByDefault` to prefer the

demos/shortform/src/main/java/androidx/media3/demo/shortform/DemoUtil.kt

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2025 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.media3.demo.shortform
+
+import android.content.Context
+import androidx.annotation.OptIn
+import androidx.media3.common.util.UnstableApi
+import androidx.media3.database.DatabaseProvider
+import androidx.media3.database.StandaloneDatabaseProvider
+import androidx.media3.datasource.cache.Cache
+import androidx.media3.datasource.cache.NoOpCacheEvictor
+import androidx.media3.datasource.cache.SimpleCache
+import java.io.File
+
+@OptIn(UnstableApi::class)
+object DemoUtil {
+
+  private const val PRECACHE_CONTENT_DIRECTORY = "precache"
+
+  private lateinit var databaseProvider: DatabaseProvider
+
+  private lateinit var downloadDirectory: File
+
+  private lateinit var downloadCache: Cache
+
+  @Synchronized
+  fun getDownloadCache(context: Context): Cache {
+    if (!::downloadCache.isInitialized) {
+      val downloadContentDirectory = File(getDownloadDirectory(context), PRECACHE_CONTENT_DIRECTORY)
+      downloadCache =
+        SimpleCache(downloadContentDirectory, NoOpCacheEvictor(), getDatabaseProvider(context))
+    }
+    return downloadCache
+  }
+
+  @Synchronized
+  private fun getDatabaseProvider(context: Context): DatabaseProvider {
+    if (!::databaseProvider.isInitialized) {
+      databaseProvider = StandaloneDatabaseProvider(context)
+    }
+    return databaseProvider
+  }
+
+  @Synchronized
+  private fun getDownloadDirectory(context: Context): File {
+    if (!::databaseProvider.isInitialized) {
+      val externalFilesDir = context.getExternalFilesDir(/* type= */ null)
+      downloadDirectory = externalFilesDir ?: context.filesDir
+    }
+    return downloadDirectory
+  }
+}

demos/shortform/src/main/java/androidx/media3/demo/shortform/MediaItemDatabase.kt

@@ -15,8 +15,11 @@
  */
 package androidx.media3.demo.shortform
 
+import androidx.annotation.OptIn
 import androidx.media3.common.MediaItem
+import androidx.media3.common.util.UnstableApi
 
+@OptIn(UnstableApi::class)
 class MediaItemDatabase {
 
   private val mediaUris =
@@ -30,6 +33,10 @@ class MediaItemDatabase {
 
   fun get(index: Int): MediaItem {
     val uri = mediaUris[index.mod(mediaUris.size)]
-    return MediaItem.Builder().setUri(uri).setMediaId(index.toString()).build()
+    return MediaItem.Builder()
+      .setUri(uri)
+      .setMediaId(index.toString())
+      .setCustomCacheKey(index.toString())
+      .build()
   }
 }

demos/shortform/src/main/java/androidx/media3/demo/shortform/viewpager/ViewPagerMediaAdapter.kt

@@ -23,11 +23,13 @@ import androidx.media3.common.C
 import androidx.media3.common.MediaItem
 import androidx.media3.common.util.Log
 import androidx.media3.common.util.UnstableApi
+import androidx.media3.demo.shortform.DemoUtil
 import androidx.media3.demo.shortform.MediaItemDatabase
 import androidx.media3.demo.shortform.PlayerPool
 import androidx.media3.demo.shortform.R
 import androidx.media3.exoplayer.DefaultLoadControl
 import androidx.media3.exoplayer.source.preload.DefaultPreloadManager
+import androidx.media3.exoplayer.source.preload.PreloadManagerListener
 import androidx.media3.exoplayer.source.preload.TargetPreloadStatusControl
 import androidx.recyclerview.widget.RecyclerView
 import kotlin.math.abs
@@ -49,7 +51,7 @@ class ViewPagerMediaAdapter(
     private const val LOAD_CONTROL_MIN_BUFFER_MS = 5_000
     private const val LOAD_CONTROL_MAX_BUFFER_MS = 20_000
     private const val LOAD_CONTROL_BUFFER_FOR_PLAYBACK_MS = 500
-    private const val MANAGED_ITEM_COUNT = 10
+    private const val MANAGED_ITEM_COUNT = 20
     private const val ITEM_ADD_REMOVE_COUNT = 4
   }
 
@@ -68,9 +70,11 @@ class ViewPagerMediaAdapter(
     val preloadManagerBuilder =
       DefaultPreloadManager.Builder(context.applicationContext, targetPreloadStatusControl)
         .setLoadControl(loadControl)
+        .setCache(DemoUtil.getDownloadCache(context.applicationContext))
     playerPool = PlayerPool(numberOfPlayers, preloadManagerBuilder)
     holderMap = mutableMapOf()
     preloadManager = preloadManagerBuilder.build()
+    preloadManager.addListener(DefaultPreloadManagerListener())
     for (i in 0 until MANAGED_ITEM_COUNT) {
       addMediaItem(index = i, isAddingToRightEnd = true)
     }
@@ -175,12 +179,18 @@ class ViewPagerMediaAdapter(
     TargetPreloadStatusControl<Int, DefaultPreloadManager.PreloadStatus> {
 
     override fun getTargetPreloadStatus(rankingData: Int): DefaultPreloadManager.PreloadStatus {
-      if (abs(rankingData - currentPlayingIndex) == 2) {
-        return DefaultPreloadManager.PreloadStatus.specifiedRangeLoaded(/* durationMs= */ 500L)
-      } else if (abs(rankingData - currentPlayingIndex) == 1) {
+      if (abs(rankingData - currentPlayingIndex) == 1) {
+        return DefaultPreloadManager.PreloadStatus.specifiedRangeLoaded(/* durationMs= */ 1000L)
+      } else if (abs(rankingData - currentPlayingIndex) <= 3) {
         return DefaultPreloadManager.PreloadStatus.specifiedRangeLoaded(/* durationMs= */ 1000L)
       }
-      return DefaultPreloadManager.PreloadStatus.PRELOAD_STATUS_NOT_PRELOADED
+      return DefaultPreloadManager.PreloadStatus.specifiedRangeCached(5000L)
+    }
+  }
+
+  inner class DefaultPreloadManagerListener : PreloadManagerListener {
+    override fun onCompleted(mediaItem: MediaItem) {
+      Log.w(TAG, "onCompleted: " + mediaItem.mediaId)
     }
   }
 }