【重生之我在学Android原生】Media3

前言

内容颇多，尽量从简

ExoPlayer使用

官方文档
参考文章

实现效果

Android（java）
使用ExoPlayer播放视频，自定义ExoPlayer界面，记录播放位置（横屏竖屏切换/切换至后台等）

案例实现

创建项目

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添加依赖

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Sync 一下

/// Jetpack Media3 ExoPlayerimplementation ("androidx.media3:media3-exoplayer:1.3.1")implementation ("androidx.media3:media3-ui:1.3.1")implementation ("androidx.media3:media3-common:1.3.1")

转到activity_main.xml

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选择Player.View

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><androidx.media3.ui.PlayerViewandroid:id="@+id/video_view"android:layout_width="match_parent"android:layout_height="match_parent"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" /></androidx.constraintlayout.widget.ConstraintLayout>

player初始化

要在Activity的生命周期中完成player的初始化销毁等
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package com.test.exoplayerexampleapplication;import androidx.annotation.OptIn;
import androidx.appcompat.app.AppCompatActivity;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import androidx.media3.ui.PlayerView;import android.os.Bundle;public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}@OptIn(markerClass = UnstableApi.class) @Overrideprotected void onStart() {super.onStart();if (Util.SDK_INT >= 24) {initializePlayer();}}@OptIn(markerClass = UnstableApi.class) @Overrideprotected void onResume() {super.onResume();if (Util.SDK_INT < 24) {initializePlayer();}}private void initializePlayer() {}
}

定义PlayerView，ExoPlayer

    private PlayerView playerView;private ExoPlayer exoPlayer;private final Uri videoOneUri = Uri.parse("http://www.w3school.com.cn/example/html5/mov_bbb.mp4");

在AndroidManifest.xml中定义网络权限，如果链接是Http，还需加userCleartextTraffic
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<uses-permission android:name="android.permission.INTERNET" />

android:usesCleartextTraffic="true"

定义initializePlayer()方法

private void initializePlayer() {playerView = findViewById(R.id.video_view);exoPlayer = new ExoPlayer.Builder(this).build();playerView.setPlayer(exoPlayer);MediaItem mediaItem = MediaItem.fromUri(videoOneUri);exoPlayer.addMediaItem(mediaItem);exoPlayer.prepare();}

运行可以播放视频
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释放资源

媒体播放器是很占用资源的，所以当不再需要播放器时，要释放它，当然也要在Activity的生命周期中释放资源
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在onStop和onPause适当调用

    @OptIn(markerClass = UnstableApi.class) @Overrideprotected void onPause() {super.onPause();if (Util.SDK_INT < 24) {releasePlayer();}}@OptIn(markerClass = UnstableApi.class) @Overrideprotected void onStop() {super.onStop();if (Util.SDK_INT >= 24) {releasePlayer();}}private void releasePlayer() {exoPlayer.release();}

记录视频的播放状态

重新运行项目，测试切换至后台
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切换至后台的生命周期，可以知道当APP放到后台，会调用player.release()方法释放

我们发现视频切换到后台，再切换回来，之前的播放到第四秒，切换回来发现，又回到第0秒。所以，现在需要记录之前播放的位置，播放的状态，播放到第几个视频了。
既然没有onDestory掉Activity
那么定义三个变量(播放位置，播放状态，第几个视频)

    private Long playbackPosition = 0L;private int currentMediaItemIndex = 0;private boolean playWhenReady = false;

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playbackPosition = exoPlayer.getCurrentPosition();currentMediaItemIndex = exoPlayer.getCurrentMediaItemIndex();playWhenReady = exoPlayer.getPlayWhenReady();

exoPlayer.setPlayWhenReady(playWhenReady);exoPlayer.seekTo(currentMediaItemIndex, playbackPosition);

添加新的视频链接

private final Uri videoTwoUri = Uri.parse("https://media.w3.org/2010/05/sintel/trailer.mp4");

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运行测试，播放下一个视频，并播放至一半，切换到后台，再切换回来

横竖屏切换

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横竖屏切换的生命周期，Activity被Destory了

使用SharedPreference来存储键值对，参考官方文档，官方推荐用DataStore
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那使用DataStore

我们现在做的事情是，使用DataStore Preference来存储视频在释放之前的播放进度，播放状态，播放到第几个视频了。
按照官网配置Preferences DataStore
引入依赖

/// Preferences DataStoreimplementation("androidx.datastore:datastore-preferences:1.0.0")/// RxJava2 supportimplementation("androidx.datastore:datastore-preferences-rxjava2:1.0.0")/// RxJava3 supportimplementation("androidx.datastore:datastore-preferences-rxjava3:1.0.0")

实例RxDataStore，销毁

private RxDataStore<Preferences> dataStore;

if (dataStore == null) {dataStore = new RxPreferenceDataStoreBuilder(this, "ExoPlayerKeys").build();}

    @Overrideprotected void onDestroy() {super.onDestroy();if (dataStore != null) {dataStore.dispose();}}

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定义三个Key

    Preferences.Key<Integer> currentMediaItemIndexPK;Preferences.Key<Integer> playbackPositionPK;Preferences.Key<Boolean> playWhenReadyPK;

currentMediaItemIndexPK = PreferencesKeys.intKey("currentMediaItemIndex");playbackPositionPK = PreferencesKeys.intKey("playbackPosition");playWhenReadyPK = PreferencesKeys.booleanKey("playWhenReady");

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使用PreferencesKeys存储值

private void saveVideoRecord() {dataStore.updateDataAsync(preferences -> {MutablePreferences mutablePreferences = preferences.toMutablePreferences();mutablePreferences.set(currentMediaItemIndexPK, currentMediaItemIndex);mutablePreferences.set(playbackPositionPK, playbackPosition.intValue());mutablePreferences.set(playWhenReadyPK, playWhenReady);return Single.just(mutablePreferences);});}

在onCreate()中取出之前存储的值，首次运行时，是没有存值的，所以会异常NULL，所以没有值就初始化这些变量
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try {currentMediaItemIndex = dataStore.data().map(preferences -> preferences.get(currentMediaItemIndexPK)).blockingFirst();} catch (Exception e) {currentMediaItemIndex = 0;}try {playbackPosition = Long.valueOf(dataStore.data().map(preferences -> preferences.get(playbackPositionPK)).blockingFirst());} catch (Exception e) {playbackPosition = 0L;}try {playWhenReady = dataStore.data().map(preferences -> preferences.get(playWhenReadyPK)).blockingFirst();} catch (Exception e) {playWhenReady = false;}

删除APP，重新运行项目，旋转屏幕也能记录播放状态，和播放进度，播放第几个视频
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旋转后，仍然从之前播放的进度继续，保持暂停。

监听事件

参考链接

@OptIn(markerClass = UnstableApi.class)private void addPlayerListener() {listener = new Player.Listener() {@OptIn(markerClass = UnstableApi.class)@Overridepublic void onPlaybackStateChanged(int playbackState) {Player.Listener.super.onPlaybackStateChanged(playbackState);String stateString = "UNKNOWN_STATE";if (playbackState == ExoPlayer.STATE_IDLE) {stateString = "EXoPlayer.STATE_IDLE";} else if (playbackState == ExoPlayer.STATE_BUFFERING) {stateString = "ExoPlayer.STATE_BUFFERING";} else if (playbackState == Player.STATE_READY) {stateString = "ExoPlayer.STATE_READY";} else if (playbackState == Player.STATE_ENDED) {stateString = "ExoPlayer.STATE_ENDED";}Log.d(TAG, "changed state to " + stateString);}};exoPlayer.addListener(listener);analyticsListener = new AnalyticsListener() {@Overridepublic void onRenderedFirstFrame(EventTime eventTime, Object output, long renderTimeMs) {AnalyticsListener.super.onRenderedFirstFrame(eventTime, output, renderTimeMs);Log.i(TAG, "AnalyticsListener - onRenderedFirstFrame - 等待多长时间才能在屏幕上看到有意义的内容 - " + renderTimeMs);}@Overridepublic void onDroppedVideoFrames(EventTime eventTime, int droppedFrames, long elapsedMs) {AnalyticsListener.super.onDroppedVideoFrames(eventTime, droppedFrames, elapsedMs);Log.i(TAG, "AnalyticsListener - onDroppedVideoFrames - 视频丢帧 - " + droppedFrames);}@Overridepublic void onAudioUnderrun(EventTime eventTime, int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs) {AnalyticsListener.super.onAudioUnderrun(eventTime, bufferSize, bufferSizeMs, elapsedSinceLastFeedMs);Log.i(TAG, "AnalyticsListener - onAudioUnderrun - 音频欠载 - " + bufferSizeMs);}};exoPlayer.addAnalyticsListener(analyticsListener);}

自定义ExoPlayer界面

按住Command键，左键查看PlayerView.java,鼠标hover在文件上，看它的位置，可以顺藤摸瓜找到它的源码

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布局界面在这里

复制到自己的项目中

在此基础上更改custom_player_control_view.xml

MediaSessionService后台播放

参考文章

实现效果

让媒体挂在后台播放，如下图
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正如官网所说，可以用在长视频，听视频。显然上面没有很多的交互，如果短视频用这个，既看不到播放的内容，也没啥交互，就还是不用MediaSession

案例实现

按照官方配置的步骤，语言还是采用Java。将构建一个MediaSession，让他在后台一直播放，同时可以自定义几个按钮，如点赞，收藏。最后监听视频是否播放。

MediaController

显然需要用到MediaSessionService和MediaController
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创建项目

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按照步骤，先new 一个ListenableFuture controllerFuture
先引入依赖

    implementation ("androidx.media3:media3-session:1.3.1")implementation ("androidx.media3:media3-exoplayer:1.3.1")implementation ("androidx.media3:media3-ui:1.3.1")implementation ("androidx.media3:media3-common:1.3.1")

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定义MediaController

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package com.test.mediasessionserviceexample;import androidx.appcompat.app.AppCompatActivity;
import androidx.media3.common.MediaItem;
import androidx.media3.common.MediaMetadata;
import androidx.media3.session.MediaController;
import androidx.media3.session.SessionToken;import android.content.ComponentName;
import android.net.Uri;
import android.os.Bundle;import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.MoreExecutors;import java.util.concurrent.ExecutionException;public class MainActivity extends AppCompatActivity {ListenableFuture<MediaController> controllerFuture;private final String mediaUrl = "https://media.w3.org/2010/05/sintel/trailer.mp4";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);SessionToken sessionToken = new SessionToken(this, new ComponentName(this, 你的服务));controllerFuture = new MediaController.Builder(this, sessionToken).buildAsync();controllerFuture.addListener(() -> {Uri uri = Uri.parse(mediaUrl);MediaMetadata metadata = new MediaMetadata.Builder().setArtist("阿笙").setTitle("我名字是视频").build();MediaItem mediaItem = new MediaItem.Builder().setMediaId("media-one").setUri(uri).setMediaMetadata(metadata).build();try {MediaController mediaController = controllerFuture.get();mediaController.setMediaItem(mediaItem);mediaController.prepare();} catch (ExecutionException | InterruptedException e) {throw new RuntimeException(e);}}, MoreExecutors.directExecutor());}@Overrideprotected void onStop() {super.onStop();MediaController.releaseFuture(controllerFuture);}
}

定义服务MediaSessionService

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package com.test.mediasessionserviceexample;import android.content.Intent;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.media3.common.Player;
import androidx.media3.exoplayer.ExoPlayer;
import androidx.media3.session.MediaSession;
import androidx.media3.session.MediaSession.ControllerInfo;
import androidx.media3.session.MediaSessionService;public class PlaybackService extends MediaSessionService {private MediaSession mediaSession = null;@Overridepublic void onCreate() {super.onCreate();ExoPlayer player = new ExoPlayer.Builder(this).build();mediaSession = new MediaSession.Builder(this, player).build();}@Nullable@Overridepublic MediaSession onGetSession(@NonNull ControllerInfo controllerInfo) {return mediaSession;}@Overridepublic void onTaskRemoved(Intent rootIntent) {super.onTaskRemoved(rootIntent);Player player = mediaSession.getPlayer();if (!player.getPlayWhenReady() || player.getMediaItemCount() == 0 || player.getPlaybackState() == Player.STATE_ENDED) {stopSelf();}}@Overridepublic void onDestroy() {super.onDestroy();mediaSession.getPlayer().release();mediaSession.release();mediaSession = null;}
}

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注册服务/申明服务

<service android:name=".PlaybackService"android:foregroundServiceType="mediaPlayback"android:exported="true"><intent-filter><action android:name="androidx.media3.session.MediaSessionService"/></intent-filter></service>

申明权限（网络、前台服务）

<uses-permission android:name="android.permission.INTERNET" /><uses-permission android:name="android.permission.FOREGROUND_SERVICE" /><uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />

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运行项目

下拉通知，可以看到这个服务，
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定义按钮CommandButton

引入图标
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    private CommandButton cBRemoveFromLikes;private CommandButton cBRemoveFromFavorites;private CommandButton cBAddToLikes;private CommandButton cBAddToFavorites;private SessionCommand sCAddToLikes;private SessionCommand sCAddToFavorites;private SessionCommand sCRemoveFromLike;private SessionCommand sCRemoveFromFavorite;private static final String SAVE_TO_LIKES = "save to likes";private static final String SAVE_TO_FAVORITES = "save to favorites";private static final String REMOVE_FROM_LIKES = "remove from likes";private static final String REMOVE_FROM_FAVORITES = "remove from favorites";

sCAddToLikes = new SessionCommand(SAVE_TO_LIKES, new Bundle());sCAddToFavorites = new SessionCommand(SAVE_TO_FAVORITES, new Bundle());sCRemoveFromLike = new SessionCommand(REMOVE_FROM_LIKES, new Bundle());sCRemoveFromFavorite = new SessionCommand(REMOVE_FROM_FAVORITES, new Bundle());cBAddToLikes = buildCommandButton(SAVE_TO_LIKES, R.drawable.like_icon, sCAddToLikes);cBAddToFavorites = buildCommandButton(SAVE_TO_FAVORITES, R.drawable.favorite_icon, sCAddToFavorites);cBRemoveFromLikes = buildCommandButton(REMOVE_FROM_LIKES, R.drawable.like_remove_icon, sCRemoveFromLike);cBRemoveFromFavorites = buildCommandButton(REMOVE_FROM_FAVORITES, R.drawable.favorite_remove_icon, sCRemoveFromFavorite);

private CommandButton buildCommandButton(String displayName, int iconResId, SessionCommand sessionCommand) {return new CommandButton.Builder().setDisplayName(displayName).setIconResId(iconResId).setSessionCommand(sessionCommand).build();}

自定义MediaSession的布局

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定义MediaSession可以使用哪些自定义命令
在MediaSession.Builder()中setCallback 回调，setCustomLayout布局

通过接收customAction的值，判断当前是什么命令，对应设置布局

class CustomMediaSessionCallback implements MediaSession.Callback {@OptIn(markerClass = UnstableApi.class)@NonNull@Overridepublic ConnectionResult onConnect(@NonNull MediaSession session, @NonNull ControllerInfo controller) {SessionCommands sessionCommands = ConnectionResult.DEFAULT_SESSION_COMMANDS.buildUpon().add(sCAddToLikes).add(sCAddToFavorites).add(sCRemoveFromLike).add(sCRemoveFromFavorite).build();return new ConnectionResult.AcceptedResultBuilder(session).setAvailableSessionCommands(sessionCommands).build();}@OptIn(markerClass = UnstableApi.class)@NonNull@Overridepublic ListenableFuture<SessionResult> onCustomCommand(@NonNull MediaSession session, @NonNull ControllerInfo controller, @NonNull SessionCommand customCommand, @NonNull Bundle args) {final CommandButton buttonOne = mediaSession.getCustomLayout().get(0);final CommandButton buttonTwo = mediaSession.getCustomLayout().get(1);switch (customCommand.customAction) {case SAVE_TO_LIKES:mediaSession.setCustomLayout(ImmutableList.of(cBRemoveFromLikes, buttonTwo));break;case SAVE_TO_FAVORITES:mediaSession.setCustomLayout(ImmutableList.of(buttonOne, cBRemoveFromFavorites));break;case REMOVE_FROM_LIKES:mediaSession.setCustomLayout(ImmutableList.of(cBAddToLikes, buttonTwo));break;case REMOVE_FROM_FAVORITES:mediaSession.setCustomLayout(ImmutableList.of(buttonOne, cBAddToFavorites));break;default:throw new RuntimeException("not implement");}return Futures.immediateFuture(new SessionResult(SessionResult.RESULT_SUCCESS));}}

运行测试

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自定义Player的行为(play等)

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        ExoPlayer player = new ExoPlayer.Builder(this).build();ForwardingPlayer forwardingPlayer = new ForwardingPlayer(player) {@Overridepublic void play() {super.play();Log.d("ForwardingPlayer Log", "play!");}};mediaSession = new MediaSession.Builder(this, forwardingPlayer).setCallback(new CustomMediaSessionCallback()).setCustomLayout(ImmutableList.of(cBAddToLikes, cBAddToFavorites)).build();

MediaLibraryService

实现目标

参考文档
主要实现三个函数

onGetLibraryRoot()
onGetChildren()
onGetSearchResult()

实现效果

创建一个目录，目录下有三个文件，并且可以根据标题搜索这三个文件
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案例实现

采用JAVA实现

创建项目接着引入依赖

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    implementation ("androidx.media3:media3-session:1.3.1")implementation ("androidx.media3:media3-exoplayer:1.3.1")implementation ("androidx.media3:media3-ui:1.3.1")implementation ("androidx.media3:media3-common:1.3.1")

初始化MediaLibraryService

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和MediaSession操作差不多，先实例

package com.test.medialibraryservicetestapplication;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.media3.common.MediaItem;
import androidx.media3.exoplayer.ExoPlayer;
import androidx.media3.session.LibraryResult;
import androidx.media3.session.MediaLibraryService;
import androidx.media3.session.MediaSession;import com.google.common.collect.ImmutableList;
import com.google.common.util.concurrent.ListenableFuture;public class PlaybackService extends MediaLibraryService {MediaLibrarySession mediaLibrarySession = null;MediaLibrarySession.Callback callback = new MediaLibrarySession.Callback() {@NonNull@Overridepublic ListenableFuture<LibraryResult<MediaItem>> onGetLibraryRoot(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @Nullable MediaLibraryService.LibraryParams params) {return MediaLibrarySession.Callback.super.onGetLibraryRoot(session, browser, params);}@NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetChildren(MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String parentId, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {return MediaLibrarySession.Callback.super.onGetChildren(session, browser, parentId, page, pageSize, params);}@NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetSearchResult(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String query, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {return MediaLibrarySession.Callback.super.onGetSearchResult(session, browser, query, page, pageSize, params);}};@Nullable@Overridepublic MediaLibrarySession onGetSession(@NonNull MediaSession.ControllerInfo controllerInfo) {return mediaLibrarySession;}@Overridepublic void onCreate() {super.onCreate();ExoPlayer player = new ExoPlayer.Builder(this).build();mediaLibrarySession = new MediaLibraryService.MediaLibrarySession.Builder(this, player, callback).build();}@Overridepublic void onDestroy() {super.onDestroy();if (mediaLibrarySession != null) {mediaLibrarySession.getPlayer().release();mediaLibrarySession.release();mediaLibrarySession = null;}}
}

创建树形结构存储数据

要获取根对象，需要有一个建好的树形数据，就如下面这幅图上，它是一个树，树的根节点RootNode，分叉出去好几个类目，简单起见，这里先弄简单的Root->Music/Game/Study
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定义树

构建根节点，添加三个子节点到根节点

最后改为单例

package com.test.medialibraryservicetestapplication;import java.util.HashMap;
import java.util.Map;public class Tree {Map<String, TreeNode> treeNodes;final String ROOT_ID = "root";final String MUSIC_ID = "music";final String GAME_ID = "game";final String STUDY_ID = "study";final String ROOT_TITLE = "root title";final String MUSIC_TITLE = "music title";final String GAME_TITLE = "game title";final String STUDY_TITLE = "study title";private final static Tree instance = new Tree();public static Tree genInstance() {return instance;}private boolean isInitialized = false;private Tree() {if (!isInitialized) {isInitialized = true;treeNodes = new HashMap<>();TreeNode rootNode = new TreeNode(ROOT_ID, ROOT_TITLE);TreeNode musicNode = new TreeNode(MUSIC_ID, MUSIC_TITLE);TreeNode gameNode = new TreeNode(GAME_ID, GAME_TITLE);TreeNode studyNode = new TreeNode(STUDY_ID, STUDY_TITLE);rootNode.children.add(musicNode.node);rootNode.children.add(gameNode.node);rootNode.children.add(studyNode.node);treeNodes.put(ROOT_ID, rootNode);}}
}

获取根节点

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MediaItem getTreeRoot() {return Objects.requireNonNull(treeNodes.get(ROOT_ID)).node;}

        @NonNull@Overridepublic ListenableFuture<LibraryResult<MediaItem>> onGetLibraryRoot(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @Nullable MediaLibraryService.LibraryParams params) {return Futures.immediateFuture(LibraryResult.ofItem(Tree.genInstance().getTreeRoot(), params));}

获取结点的子节点集合

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    List<MediaItem> getNodeChildren(String treeNodeId) {return Objects.requireNonNull(treeNodes.get(treeNodeId)).children;}

@NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetChildren(MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String parentId, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {List<MediaItem> children = Tree.genInstance().getNodeChildren(parentId);if (!children.isEmpty()) {return Futures.immediateFuture(LibraryResult.ofItemList(children, params));}return Futures.immediateFuture(LibraryResult.ofError(LibraryResult.RESULT_ERROR_BAD_VALUE));}

注册Service及申明权限

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<uses-permission android:name="android.permission.FOREGROUND_SERVICE" /><uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />

<serviceandroid:name=".PlaybackService"android:exported="true"android:foregroundServiceType="mediaPlayback"><intent-filter><action android:name="androidx.media3.session.MediaSessionService" /></intent-filter></service>

MediaBrowser浏览MediaLibraryService定义的媒体库

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获取MediaLibraryService构建的媒体库的根节点

获取某一节点下的子节点

运行测试

运行项目，并在60行打上断点，看到value属性值为三个MediaItem对象
可以看到获取到根节点下的三个子节点
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package com.test.medialibraryservicetestapplication;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.media3.common.MediaItem;
import androidx.media3.exoplayer.ExoPlayer;
import androidx.media3.session.LibraryResult;
import androidx.media3.session.MediaLibraryService;
import androidx.media3.session.MediaSession;import com.google.common.collect.ImmutableList;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;import java.util.List;public class PlaybackService extends MediaLibraryService {MediaLibrarySession mediaLibrarySession = null;MediaLibrarySession.Callback callback = new MediaLibrarySession.Callback() {@NonNull@Overridepublic ListenableFuture<LibraryResult<MediaItem>> onGetLibraryRoot(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @Nullable MediaLibraryService.LibraryParams params) {return Futures.immediateFuture(LibraryResult.ofItem(Tree.genInstance().getTreeRoot(), params));}@NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetChildren(MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String parentId, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {List<MediaItem> children = Tree.genInstance().getNodeChildren(parentId);if (!children.isEmpty()) {return Futures.immediateFuture(LibraryResult.ofItemList(children, params));}return Futures.immediateFuture(LibraryResult.ofError(LibraryResult.RESULT_ERROR_BAD_VALUE));}@NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetSearchResult(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String query, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {return MediaLibrarySession.Callback.super.onGetSearchResult(session, browser, query, page, pageSize, params);}};@Nullable@Overridepublic MediaLibrarySession onGetSession(@NonNull MediaSession.ControllerInfo controllerInfo) {return mediaLibrarySession;}@Overridepublic void onCreate() {super.onCreate();ExoPlayer player = new ExoPlayer.Builder(this).build();mediaLibrarySession = new MediaLibraryService.MediaLibrarySession.Builder(this, player, callback).build();}@Overridepublic void onDestroy() {super.onDestroy();if (mediaLibrarySession != null) {mediaLibrarySession.getPlayer().release();mediaLibrarySession.release();mediaLibrarySession = null;}}
}

搜索媒体库

首先还是去Tree中定义搜索的函数
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    List<MediaItem> search(String query) {List<MediaItem> titleMatches = new ArrayList<>();Object[] words = Arrays.stream(query.split(" ")).map(it -> it.trim().toLowerCase()).filter(it -> it.length() > 1).toArray();titleNodes.keySet().forEach(title -> {TreeNode treeNode = titleNodes.get(title);for (Object word : words) {boolean contains = title.contains((CharSequence) word);if (contains) {assert treeNode != null;titleMatches.add(treeNode.node);}}});return titleMatches;}

    public static Map<String, TreeNode> titleNodes;
titleNodes = new HashMap<>();titleNodes.put(MUSIC_TITLE, musicNode);titleNodes.put(GAME_TITLE, gameNode);titleNodes.put(STUDY_TITLE, studyNode);

在这里插入图片描述

        @NonNull@Overridepublic ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetSearchResult(@NonNull MediaLibrarySession session, @NonNull MediaSession.ControllerInfo browser, @NonNull String query, int page, int pageSize, @Nullable MediaLibraryService.LibraryParams params) {return Futures.immediateFuture(LibraryResult.ofItemList(Tree.genInstance().search(query), params));}

MediaBrowser 搜索

    private void searchMedia(String query) {ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> searchFuture = mediaBrowser.getSearchResult(query, 0, Integer.MAX_VALUE, null);searchFuture.addListener(() -> {try {LibraryResult<ImmutableList<MediaItem>> immutableListLibraryResult = searchFuture.get();ImmutableList<MediaItem> value = immutableListLibraryResult.value;} catch (ExecutionException | InterruptedException e) {throw new RuntimeException(e);}}, MoreExecutors.directExecutor());}