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。

// ExoPlayerimplementation 'com.google.android.exoplayer:exoplayer-core:2.10.5'implementation 'com.google.android.exoplayer:exoplayer-ui:2.10.5'// AndroidVideoCacheimplementation '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

前言

效果

ExoPlayer使用

MediaPlayerManager定义

Tips:

案例

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