Exoplayer2实现边播放边缓存

前言

ExoPlayer是Google开源的一款Android应用程序级的媒体播放器。它提供了Android MediaPlayer API的替代方法，可以在本地和Internet上播放音频和视频。ExoPlayer支持Android MediaPlayer API当前不支持的功能，包括DASH和SmoothStreaming自适应播放。与MediaPlayer API不同，ExoPlayer易于自定义和扩展。这里主要使用 ExoPlayer + AndroidVideoCache 实现边播放边缓存。下面点击可查看对应库和文档。

• ExoPlayer
• ExoPlayer Javadoc
• ExoPlayer Release
• AndroidVideoCache

效果

ExoPlayer使用

添加ExoPlayer与AndroidVideoCache依赖，我这边使用的是ExoPlayer v2.10.5和AndroidVideoCache v2.7.1版本，可根据自身需求升级或降级。

// ExoPlayer implementation 'com.google.android.exoplayer:exoplayer-core:2.10.5' implementation 'com.google.android.exoplayer:exoplayer-ui:2.10.5' // AndroidVideoCache implementation 'com.danikula:videocache:2.7.1' 

依赖添加完成后在Layout中使用ExoPlayer库中的PlayerView组件。

 <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent" android:layout_height="match_parent"> <com.google.android.exoplayer2.ui.PlayerView
            android:id="@+id/media_player_view" android:layout_width="0dp" android:layout_height="0dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> <androidx.core.widget.ContentLoadingProgressBar
            android:id="@+id/media_video_progress" style="?android:attr/progressBarStyleLarge" android:layout_width="40dp" android:layout_height="40dp" android:indeterminateTint="@color/colorAccent" android:indeterminateTintMode="src_atop" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> </androidx.constraintlayout.widget.ConstraintLayout> 

具体使用，使用了DataBinding，不明白的朋友可在评论区评论，尽量及时给你回复。

class MainActivity : AppCompatActivity() { companion object { private const val MEDIA_URI: String = "http://wxsnsdy.tc.qq.com/105/20210/snsdyvideodownload?filekey=30280201010421301f0201690402534804102ca905ce620b1241b726bc41dcff44e00204012882540400&bizid=1023&hy=SH&fileparam=302c020101042530230204136ffd93020457e3c4ff02024ef202031e8d7f02030f42400204045a320a0201000400" } private lateinit var binding: ActivityMainBinding private var mStartPosition = 0 private var mPlaybackProgressPosition = 0L // 自适应音轨 private val mTrackSelectionFactory by lazy { AdaptiveTrackSelection.Factory() } // 创建播放器 private val mPlayer by lazy { ExoPlayerFactory.newSimpleInstance( this, DefaultRenderersFactory(this), DefaultTrackSelector(mTrackSelectionFactory), DefaultLoadControl() ) } private val mOnVideoEventListener by lazy { OnVideoEventListener() } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) binding = DataBindingUtil.setContentView(this, R.layout.activity_main) binding.lifecycleOwner = this binding.data = this binding.executePendingBindings() initView() } private fun initView() { // 将播放器连接到视图 binding.mediaPlayerView.player = mPlayer
        mPlayer?.addListener(mOnVideoEventListener) } override fun onResume() { super.onResume() updatePlaybackProgress() playbackVideo() } override fun onPause() { super.onPause() mPlayer?.stop() } override fun onDestroy() { super.onDestroy() mPlayer?.removeListener(mOnVideoEventListener) } /**
     * 播放视频
     */ private fun playbackVideo() { clearPlaybackProgress() if (mPlayer != null) { // 设置播放进度 val mHaveStartPosition = mStartPosition != C.INDEX_UNSET if (mHaveStartPosition){ mPlayer.seekTo(mStartPosition, mPlaybackProgressPosition) } @C.ContentType val mMediaSourceType = Util.inferContentType(Uri.parse(MEDIA_URI), null) if(mMediaSourceType == C.TYPE_OTHER) { // 获取构建后的媒体资源 val mMediaSource = MediaPlayerManager.getDefault().buildDataSource(this, MEDIA_URI) // 将媒体资源设置给播放器 mPlayer.prepare(mMediaSource, !mHaveStartPosition, true) // 是否是自动播放 mPlayer.playWhenReady = true } else { Log.e(javaClass.simpleName, "播放媒体资源出错，类型不支持，错误类型：$mMediaSourceType") return } } } /**
     * 视频播放事件监听
     */ private inner class OnVideoEventListener: Player.EventListener{ override fun onPlayerStateChanged(playWhenReady: Boolean, playbackState: Int) { if (playbackState == ExoPlayer.STATE_BUFFERING){ binding.mediaVideoProgress.show() }else { binding.mediaVideoProgress.hide() } } override fun onIsPlayingChanged(isPlaying: Boolean) { val mPlayerChange = !isPlaying && mPlayer?.playbackState == Player.STATE_ENDED if (mPlayerChange) clearPlaybackProgress() if (mPlayerChange) { Toast.makeText(this@MainActivity, "播放完成！", Toast.LENGTH_SHORT).show() } } override fun onPlayerError(error: ExoPlaybackException?) { binding.mediaVideoProgress.hide() clearPlaybackProgress() Toast.makeText(this@MainActivity, "播放出现错，${error?.message}！", Toast.LENGTH_SHORT).show() } } /**
     * 更新播放进度
     */ private fun updatePlaybackProgress() { mStartPosition = mPlayer?.currentWindowIndex ?: 0 mPlaybackProgressPosition = max(0, (mPlayer?.contentPosition ?: 0)) } /**
     * 清除播放位置
     */ private fun clearPlaybackProgress() { mStartPosition = C.INDEX_UNSET
        mPlaybackProgressPosition = C.TIME_UNSET
        mPlayer?.stop() } } 

MediaPlayerManager定义

主要使用AndroidVideoCache中的HttpProxyCacheServer来缓存数据资源，使用ExoPlayer中的DefaultDataSourceFactory来决定数据加载策略。

class MediaPlayerManager { private var mUserAgent = this.javaClass.simpleName // 视频加载代理 @Volatile private var mProxyCacheServer: HttpProxyCacheServer? = null companion object{ private const val DISK_CACHE_DIR_NAME = "Video" @Volatile private var INSTANCES: MediaPlayerManager? = null fun getDefault(): MediaPlayerManager = INSTANCES ?: synchronized(this){ MediaPlayerManager().also { INSTANCES = it }} } fun init(context: Context, userAgent: String) { mProxyCacheServer = createProxyCacheServer(context) mUserAgent = Util.getUserAgent(context, userAgent) } /**
     * 将传入的uri构建为一个规媒体资源
     *
     * DashMediaSource         DASH.
     * SsMediaSource           SmoothStreaming.
     * HlsMediaSource          HLS.
     * ProgressiveMediaSource  常规媒体文件.
     *
     * @return 返回一个常规媒体资源
     */ fun buildDataSource(context: Context, uri: String): MediaSource { // 构建一个默认的Http数据资源处理工厂 val mHttpDataSourceFactory = DefaultHttpDataSourceFactory(mUserAgent) // DefaultDataSourceFactory决定数据加载模式，是从网络加载还是本地缓存加载 val mDataSourceFactory = DefaultDataSourceFactory(context, mHttpDataSourceFactory) // AndroidVideoCache库不支持DASH, SS(Smooth Streaming：平滑流媒体，如直播流), HLS数据格式，所以这里使用一个常见媒体转换数据资源工厂 return ProgressiveMediaSource.Factory(mDataSourceFactory).createMediaSource(Uri.parse(getProxyUrl(uri))) } /**
     * 创建视频加载代理
     */ private fun createProxyCacheServer(context: Context): HttpProxyCacheServer { return HttpProxyCacheServer.Builder(context) .cacheDirectory(getDiskCacheDirectory(context)) // 设置磁盘存储地址 .maxCacheSize(1024 * 1024 * 1024) // 设置可存储1G资源 .build() } /**
     * 获取代理地址
     */ fun getProxyUrl(url: String): String? = mProxyCacheServer?.getProxyUrl(url) /**
     * 是否缓存
     * @return true:已经缓存
     */ fun isCached(url: String) = mProxyCacheServer?.isCached(url) ?: false /**
     * 视频磁盘缓存地址
     */ @SuppressLint("SdCardPath") fun getDiskCacheDirectory(context: Context): File { var cacheDir: File? = null if (Environment.MEDIA_MOUNTED == getExternalStorageState()) { cacheDir = getExternalCacheDir(context) } if (cacheDir == null) { cacheDir = context.cacheDir } if (cacheDir == null) { val cacheDirPath = "/data/data/${context.packageName}/cache/" cacheDir = File(cacheDirPath) } return File(cacheDir, DISK_CACHE_DIR_NAME) } private fun getExternalStorageState(): String { return try { Environment.getExternalStorageState() } catch (e: NullPointerException) { "" } } private fun getExternalCacheDir(context: Context): File? { val cacheDir = context.getExternalFilesDir("Cache") if (!cacheDir?.exists()!!) { if (!cacheDir.mkdirs()) { return null } } return cacheDir } /**
     * 删除所有视频缓存
     */ @Throws(IOException::class) fun deleteAllCache(context: Context) { val mFile = getDiskCacheDirectory(context) if (!mFile.exists()) return val mFiles = mFile.listFiles() if (!mFiles.isNullOrEmpty() && mFiles.isNotEmpty()) { mFiles.forEach { deleteVideoCache(it) } } } /**
     * 删除视频缓存
     */ @Throws(IOException::class) private fun deleteVideoCache(file: File) { if (file.isFile && file.exists()) { val isDeleted = file.delete() Log.e(javaClass.simpleName, "删除视频缓存：${file.path}\t删除状态：$isDeleted") } } /**
     * 获取磁盘缓存的数据大小，单位：KB
     */ fun getDiskCacheSize(context: Context): Long { val file = getDiskCacheDirectory(context) var blockSize = 0L try { blockSize = if (file.isDirectory) getFileSizes(file) else getFileSize(file) } catch (e: Exception) { e.printStackTrace() } return blockSize } private fun getFileSizes(file: File): Long { var size = 0L file.listFiles()?.forEach { if (it.isDirectory) { size += getFileSizes(it) } else { try { size += getFileSize(it) } catch (e: Exception) { e.printStackTrace() } } } return size } private fun getFileSize(file: File): Long { var size = 0L if (file.exists()) { FileInputStream(file).use { size = it.available().toLong() } } return size } } 

Tips:

• MediaPlayerManager 类中定义了缓存函数 getDiskCacheDirectory
• 缓存目标默认地址为：/storage/emulated/0/Android/data/应用包名/files/Cache/Video/目标文件

对Android本地磁盘有兴趣的可以看看我这篇：Android存储路径探索

案例

码云Gitee

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