M3U8视频下载实现

前段时间由于业务需要，需要做一个视频下载的功能，包括m3u8视频和mp4视频等，于是在Github上找了几个相关的下载库，发现要不是太久没有更新了，要不就是不太符合我们的需求，所以干脆就手撸了一个M3U8Downloader

Github地址：https://github.com/xuqingquan1995/M3U8Downloader

Gitee地址：https://gitee.com/xuqingquan/M3U8Downloader

M3U8文件结构

开始撸代码之前，先预备一下相关知识，M3U8视频其实主要就一个文件，文件里面写明了视频片段ts的地址，我们获得这个m3u8文件就可以通过文件内的内容，分析出世纪的ts，然后下载相对应的ts文件，就可以做到下载m3u8视频了

最直接的m3u8文件

https://135zyv5.xw0371.com/2018/10/29/X05c7CG3VB91gi1M/playlist.m3u8
这个链接的m3u8文件下载后内容如下

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-ALLOW-CACHE:YES
#EXT-X-TARGETDURATION:19
#EXTINF:12.640000,
out000.ts
#EXTINF:7.960000,
out001.ts
#EXTINF:12.280000,
out002.ts
#EXTINF:7.520000,
out003.ts
#EXTINF:10.240000,
out004.ts
#EXTINF:15.520000,
out005.ts
#EXTINF:8.600000,
out006.ts
#EXTINF:7.440000,
out007.ts
#EXTINF:8.240000,
out008.ts
#EXTINF:10.000000,
out009.ts
#EXTINF:13.120000,
out010.ts
。。。。。。。

可以很直观的看出，其实这个文件里面是一系列的ts文件

需要重定向的m3u8

还有例如以下这两个链接的m3u8文件下载后内容如下,只有简单的一行

http://youku.cdn-iqiyi.com/20180523/11112_b1fb9d8b/index.m3u8

#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=800000,RESOLUTION=1080x608
1000k/hls/index.m3u8

https://v8.yongjiu8.com/20180321/V8I5Tg8p/index.m3u8

#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1000000,RESOLUTION=1280x720
/ppvod/1F94756C565EC42C5735D57272032622.m3u8

对于这一类的m3u8文件，其实是需要重定向的，重定向后可以获得真实的m3u8地址，从而获取到对应的ts地址

根据url规则，以上两个m3u8的实际地址为：

http://youku.cdn-iqiyi.com/20180523/11112_b1fb9d8b/index.m3u8 转为：http://youku.cdn-iqiyi.com/20180523/11112_b1fb9d8b/1000k/hls/index.m3u8

https://v8.yongjiu8.com/20180321/V8I5Tg8p/index.m3u8 转为：https://v8.yongjiu8.com/ppvod/1F94756C565EC42C5735D57272032622.m3u8

ts文件分析

对于获取到的ts文件主要有以下几种类型：

只有文件名

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:9
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:4.276000,
65f7a658c87000.ts
#EXTINF:4.170000,
65f7a658c87001.ts
#EXTINF:5.754600,
65f7a658c87002.ts
#EXTINF:4.170000,
65f7a658c87003.ts
#EXTINF:4.170000,

带有路径的

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:10,
/20180321/V8I5Tg8p/1000kb/hls/bdmhnU1119000.ts
#EXTINF:10,
/20180321/V8I5Tg8p/1000kb/hls/bdmhnU1119001.ts
#EXTINF:10,
/20180321/V8I5Tg8p/1000kb/hls/bdmhnU1119002.ts
#EXTINF:10,
/20180321/V8I5Tg8p/1000kb/hls/bdmhnU1119003.ts
#EXTINF:7.8,
/20180321/V8I5Tg8p/1000kb/hls/bdmhnU1119004.ts

其实也是根据url规则进行替换，对于只有文件名的ts文件，只要把它对应的m3u8地址最后的文件名替换成ts文件名就行了，对于带有路径的，根据url规则，如果以/开头的，则代表是在域名根目录下的，不是/开头的，则代表是在当前目录下的，进行相应替换就可以得到ts文件的url地址了

技术选型

既然是下载，免不了的是涉及到网络请求的实现，其实就是具体的下载怎么去做，在Github上有找到一个okdownload这个库，之所以选择它，一方面是他是下载库star最多的FileDownloader的升级版,另一方面是它的批下载功能符合我下载m3u8这样多个ts文件的场景

代码实现

数据类型准备

VideoDownloadEntity主要是存储过程中的数据，并且方便之后操作的

const val NO_START = 0
const val PREPARE = 1
const val DOWNLOADING = 2
const val PAUSE = 3
const val COMPLETE = 4
const val ERROR = 5
const val DELETE = -1class VideoDownloadEntity(var originalUrl: String,//原始下载链接var name: String = "",//视频名称var subName: String = "",//视频子名称var redirectUrl: String = "",//重定向后的下载链接var fileSize: Long = 0,//文件总大小var currentSize: Long = 0,//当前已下载大小var currentProgress: Double = 0.0,//当前进度var currentSpeed: String = "",//当前速率var tsSize: Int = 0,//ts的数量var createTime: Long = System.currentTimeMillis()//创建时间
) : Parcelable, Comparable<VideoDownloadEntity> {//状态var status: Int = NO_STARTset(value) {if (field != DELETE) {field = value}if (value == DELETE) {startDownload = nulldownloadContext?.stop()downloadTask?.cancel()}}var downloadContext: DownloadContext? = nullvar downloadTask: DownloadTask? = nullvar startDownload: (() -> Unit)? = nullconstructor(parcel: Parcel) : this(parcel.readString() ?: "",parcel.readString() ?: "",parcel.readString() ?: "",parcel.readString() ?: "",parcel.readLong(),parcel.readLong(),parcel.readDouble(),parcel.readString() ?: "",parcel.readInt(),parcel.readLong()) {this.status = parcel.readInt()}override fun writeToParcel(parcel: Parcel, flags: Int) {parcel.writeString(originalUrl)parcel.writeString(name)parcel.writeString(subName)parcel.writeString(redirectUrl)parcel.writeLong(fileSize)parcel.writeLong(currentSize)parcel.writeDouble(currentProgress)parcel.writeString(currentSpeed)parcel.writeInt(tsSize)parcel.writeLong(createTime)parcel.writeInt(status)}override fun describeContents(): Int {return 0}companion object CREATOR : Parcelable.Creator<VideoDownloadEntity> {override fun createFromParcel(parcel: Parcel): VideoDownloadEntity {return VideoDownloadEntity(parcel)}override fun newArray(size: Int): Array<VideoDownloadEntity?> {return arrayOfNulls(size)}}override fun toString(): String {val json = JSONObject()json.put("originalUrl", originalUrl)json.put("name", name)json.put("subName", subName)json.put("redirectUrl", redirectUrl)json.put("fileSize", fileSize)json.put("currentSize", currentSize)json.put("currentProgress", currentProgress)json.put("currentSpeed", currentSpeed)json.put("tsSize", tsSize)json.put("createTime", createTime)json.put("status", status)return json.toString()}fun toFile() {val path = FileDownloader.getDownloadPath(originalUrl)val config = File(path, "video.config")if (!config.exists() && this.createTime == 0L) {this.createTime = System.currentTimeMillis()}config.writeText(toString())}override fun compareTo(other: VideoDownloadEntity) =(other.createTime - this.createTime).toInt()
}fun parseJsonToVideoDownloadEntity(jsonString: String): VideoDownloadEntity? {if (jsonString.isEmpty()) {return null}return try {val json = JSONObject(jsonString)val entity = VideoDownloadEntity(json.getString("originalUrl"),json.getString("name"),json.getString("subName"),json.getString("redirectUrl"),json.getLong("fileSize"),json.getLong("currentSize"),json.getDouble("currentProgress"),json.getString("currentSpeed"),json.getInt("tsSize"),json.getLong("createTime"))entity.status = json.getInt("status")entity} catch (t: Throwable) {t.printStackTrace()null}
}

获取真实ts路径

下载m3u8文件，最开始是获取到真实的ts文件，那么先创建一个M3U8ConfigDownloader进行配置文件的获取

internal object M3U8ConfigDownloader {private val downloadList = arrayListOf<String>()private val TAG = "M3U8ConfigDownloader"//清楚所有任务，fun clear() {downloadList.clear()}/*** @return 如果返回空则不需要下载，如果返回的文件存在了，则开始下载，否则等待下载完成*/fun start(entity: VideoDownloadEntity): File? {if (entity.status == DELETE) {return null}if (downloadList.contains(entity.originalUrl)) {return null}if (entity.createTime == 0L) {entity.createTime = System.currentTimeMillis()}entity.redirectUrl = ""val path = FileDownloader.getDownloadPath(entity.originalUrl)val config = FileDownloader.getConfigFile(entity.originalUrl)val realEntity = if (!config.exists()) {entity.toFile()entity} else {parseJsonToVideoDownloadEntity(config.readText()) ?: entity}if (entity.status == DELETE) {path.deleteRecursively()return null}val m3u8ListFile = File(path, "m3u8.list")return if (realEntity.status != COMPLETE) {//没有完成的才有必要下载Log.d(TAG, "init")if (m3u8ListFile.exists()) {Log.d(TAG, "从文件下载")} else {Log.d(TAG, "从0开始下载")realEntity.status = PREPAREFileDownloader.downloadCallback.postValue(realEntity)entity.toFile()//进入下载m3u8downloadM3U8File(path, realEntity)}m3u8ListFile} else {null}}/*** 下载单个文件*/private fun downloadM3U8File(path: File, entity: VideoDownloadEntity) {if (entity.status == DELETE) {return}val fileName: Stringval url = if (entity.redirectUrl.isNotEmpty()) {//如果有了重定向的urlfileName = "real.m3u8"entity.redirectUrl} else {//否则就用初始的urlfileName = "original.m3u8"entity.originalUrl}Log.d(TAG, "downloadM3U8File-url=$url,fileName=$fileName")val downloadFile = File(path, fileName)DownloadTask.Builder(url, downloadFile.parentFile).setFilename(downloadFile.name).build().enqueue(object : DownloadListener1() {override fun taskStart(task: DownloadTask, model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}Log.d(TAG, "taskStart-->")downloadList.add(task.url)}override fun taskEnd(task: DownloadTask, cause: EndCause, realCause: Exception?,model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}Log.d(TAG, "taskEnd-->${cause.name},${realCause?.message}")if (cause == EndCause.COMPLETED) {getFileContent(path, entity)} else {entity.status = ERRORdownloadList.remove(entity.originalUrl)entity.startDownload = {start(entity)}entity.toFile()FileDownloader.downloadCallback.postValue(entity)}}override fun progress(task: DownloadTask, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}}override fun connected(task: DownloadTask, blockCount: Int, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}Log.d(TAG, "connected-->")}override fun retry(task: DownloadTask, cause: ResumeFailedCause) {if (entity.downloadTask == null) {entity.downloadTask = task}}})}/*** 分析文件内容*/private fun getFileContent(path: File, entity: VideoDownloadEntity) {if (entity.status == DELETE) {return}Log.d(TAG, "getFileContent---$entity")val url = if (entity.redirectUrl.isNotEmpty()) {//如果有了重定向的urlentity.redirectUrl} else {//否则就用初始的urlentity.originalUrl}val uri = Uri.parse(url)val realM3U8File = File(path, "real.m3u8")var file = realM3U8Fileif (!file.exists()) {//直接判断真实的m3u8文件是否存在，存在则读取file = File(path, "original.m3u8")}Log.d(TAG, "getFileContent---${file.name}")val list = file.readLines().filter { !it.startsWith("#") }//读取m3u8文件if (list.size > 1) {//直接的m3u8的ts链接entity.tsSize = list.sizeentity.toFile()if (file != realM3U8File) {file.copyTo(realM3U8File)}val m3u8ListFile = File(path, "m3u8.list")list.forEach {val ts = if (!it.startsWith("/")) {url.substring(0, url.lastIndexOf("/") + 1) + it} else {"${uri.scheme}://${uri.host}$it"}m3u8ListFile.appendText("$ts\n")}val localPlaylist = File(path, "localPlaylist.m3u8")file.readLines().forEach {var str = itif (!str.startsWith("#")) {str = if (str.contains("/")) {".ts${it.substring(it.lastIndexOf("/"))}"} else {".ts/$it"}}localPlaylist.appendText("$str\n")}Log.d(TAG, "start--->$entity")} else {//重定向val newUrl = list[0]entity.redirectUrl = if (newUrl.startsWith("/")) {"${uri.scheme}://${uri.host}$newUrl"} else {url.substring(0, url.lastIndexOf("/") + 1) + newUrl}entity.toFile()downloadM3U8File(path, entity)}}}

在以上代码中，从一个最初始的url开始，下载对应的m3u8文件，分析如果这个m3u8是最终的ts流，将ts流的完整url写入m3u8.list这个文件，之后下载的都从这个文件进行下,如果这个m3u8需要重定向，那么就重组链接，再一次下载，以此循环得到最终的ts流，同时，在获取到最终ts流到时候，会构造一个本地可以播放到m3u8文件localPlaylist.m3u8，当视频下载完成之后就可以通过这个文件打开本地的播放器进行播放

下载ts文件

之前已经获取到真实的ts路径了，并且将这些路径保存在m3u8.list文件里面了，所以之后就是通过这个文件里面的路径，使用okdownload进行批量下载了，具体实现如下

internal object M3U8Downloader {private val downloadList = arrayListOf<String>()private const val TAG = "---M3U8Downloader---"//清楚所有任务fun clear() {downloadList.clear()}//批下载fun bunchDownload(path: File) {val config = FileDownloader.getConfigFile(path)Log.d(TAG, "config==>${config.readText()}")val entity = parseJsonToVideoDownloadEntity(config.readText())if (entity == null) {//获取到的实体类为空的忽略Log.d(TAG, "entity==null${config.readText()}")return}//如果状态是删除的就忽略if (entity.status == DELETE) {path.deleteRecursively()return}//避免重复进入下载if (downloadList.contains(entity.originalUrl)) {Log.d(TAG, "contains")return}var lastCallback = 0Lval CURRENT_PROGRESS = entity.originalUrl.hashCode()val speedCalculator = SpeedCalculator()val listener = object : DownloadListener1() {override fun taskStart(task: DownloadTask, model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}}override fun taskEnd(task: DownloadTask, cause: EndCause, realCause: Exception?,model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}}override fun progress(task: DownloadTask, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}val preOffset = (task.getTag(CURRENT_PROGRESS) as Long?) ?: 0speedCalculator.downloading(currentOffset - preOffset)val now = System.currentTimeMillis()if (now - lastCallback > 1000) {entity.currentSpeed = speedCalculator.speed() ?: ""entity.status = DOWNLOADINGentity.toFile()FileDownloader.downloadCallback.postValue(entity)lastCallback = now}task.addTag(CURRENT_PROGRESS, currentOffset)}override fun connected(task: DownloadTask, blockCount: Int, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}}override fun retry(task: DownloadTask, cause: ResumeFailedCause) {if (entity.downloadTask == null) {entity.downloadTask = task}}}Log.d(TAG, "bunchDownload")val m3u8ListFile = File(path, "m3u8.list")var urls = m3u8ListFile.readLines()var times = 5while (times > 0 && urls.size != entity.tsSize) {//如果还有重试机会且ts数量还不完全对的话,等待100msurls = m3u8ListFile.readLines()times--Thread.sleep(100)}val tsDirectory = File(path, ".ts")if (!tsDirectory.exists()) {tsDirectory.mkdir()}val builder = DownloadContext.QueueSet().setParentPathFile(tsDirectory).setMinIntervalMillisCallbackProcess(1000).setPassIfAlreadyCompleted(true).commit()Log.d(TAG, "ts.size===>${urls.size}")urls.forEachIndexed { index, url ->builder.bind(url).addTag(1, index)}val downloadContext = builder.setListener(object : DownloadContextListener {override fun taskEnd(context: DownloadContext, task: DownloadTask, cause: EndCause,realCause: Exception?, remainCount: Int) {if (entity.downloadTask == null) {entity.downloadTask = task}if (entity.downloadContext == null) {entity.downloadContext = context}if (context.isStarted && cause == EndCause.COMPLETED) {val progress = 1 - (remainCount * 1.0) / urls.sizeentity.status = DOWNLOADINGentity.currentProgress = progressentity.fileSize += task.file?.length() ?: 0entity.currentSize += task.file?.length() ?: 0val now = System.currentTimeMillis()if (now - lastCallback > 1000) {FileDownloader.downloadCallback.postValue(entity)lastCallback = now}entity.toFile()}}override fun queueEnd(context: DownloadContext) {Log.d(TAG, "queueEnd")if (entity.downloadContext == null) {entity.downloadContext = context}when (entity.currentProgress) {1.0 -> entity.status = COMPLETE0.0 -> entity.status = ERRORelse -> entity.status = PAUSE}entity.toFile()FileDownloader.downloadCallback.postValue(entity)FileDownloader.subUseProgress(entity.originalUrl)//已使用的线程数减少}}).build()entity.downloadContext = downloadContextentity.startDownload = { downloadContext.startOnSerial(listener) }downloadContext.startOnSerial(listener)FileDownloader.addUseProgress(entity.originalUrl)//已使用的线程数增加downloadList.add(entity.originalUrl)}
}

通过以上代码就可以进行批量下载的实现了

MP4下载

既然对于复杂的m3u8都能下载,那么单个文件的mp4之类的肯定要支持下载的，以下为mp4的下载方案

internal object SingleVideoDownloader {private val downloadList = arrayListOf<String>()private const val TAG = "SingleVideoDownloader"//清理所有任务fun clear() {downloadList.clear()}//下载任务的初始化fun initConfig(entity: VideoDownloadEntity): File {val config = FileDownloader.getConfigFile(entity.originalUrl)if (!config.exists()) {if (entity.createTime == 0L) {entity.createTime = System.currentTimeMillis()}entity.status = PREPAREentity.fileSize = 0entity.currentSize = 0entity.toFile()Log.d(TAG, "config==>${config.readText()}")FileDownloader.downloadCallback.postValue(entity)}return config}//下载任务的入口fun fileDownloader(entity: VideoDownloadEntity) {val path = FileDownloader.getDownloadPath(entity.originalUrl)if (entity.status == DELETE) {//如果是删除状态的则忽略path.deleteRecursively()return}if (downloadList.contains(entity.originalUrl)) {//避免重复下载Log.d(TAG, "contains---${entity.originalUrl},${entity.name}")return}entity.status = PREPAREentity.fileSize = 0entity.currentSize = 0FileDownloader.downloadCallback.postValue(entity)var lastCallback = 0Lval CURRENT_PROGRESS = entity.originalUrl.hashCode()val speedCalculator = SpeedCalculator()Log.d(TAG, "fileDownloader")val fileName = if (entity.name.isNotEmpty()) {//主标题有if (entity.subName.isNotEmpty()) {//副标题也有"${entity.name}-${entity.subName}.mp4"} else {//只有主标题"${entity.name}.mp4"}} else {//没有主标题if (entity.subName.isNotEmpty()) {//只有副标题"${entity.subName}.mp4"} else {//标题都没有"index.mp4"}}val downloadFile = File(path, fileName)Log.d(TAG, "downloadFile===>${downloadFile.absolutePath}")val task = DownloadTask.Builder(entity.originalUrl, downloadFile.parentFile).setFilename(downloadFile.name).setPassIfAlreadyCompleted(true).setMinIntervalMillisCallbackProcess(1000).setConnectionCount(3).build()task.enqueue(object : DownloadListener1() {override fun taskStart(task: DownloadTask, model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}Log.d(TAG, "taskStart-->")entity.status = PREPAREentity.fileSize = 0entity.currentSize = 0entity.toFile()FileDownloader.downloadCallback.postValue(entity)}override fun taskEnd(task: DownloadTask, cause: EndCause, realCause: Exception?,model: Listener1Assist.Listener1Model) {if (entity.downloadTask == null) {entity.downloadTask = task}Log.d(TAG, "taskEnd-->${cause.name},${realCause?.message}")when (cause) {EndCause.COMPLETED -> entity.status = COMPLETEEndCause.CANCELED -> {entity.status = PAUSEentity.startDownload = {fileDownloader(entity)}}else -> {entity.status = ERRORentity.startDownload = {fileDownloader(entity)}}}entity.toFile()FileDownloader.downloadCallback.postValue(entity)downloadList.remove(entity.originalUrl)FileDownloader.subUseProgress(task.url)//已使用的线程数减少}override fun progress(task: DownloadTask, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}val preOffset = (task.getTag(CURRENT_PROGRESS) as Long?) ?: 0speedCalculator.downloading(currentOffset - preOffset)entity.currentSize = currentOffsetval now = System.currentTimeMillis()if (now - lastCallback > 1000) {entity.currentProgress = (currentOffset * 1.0) / (totalLength * 1.0)entity.currentSpeed = speedCalculator.speed() ?: ""entity.status = DOWNLOADINGentity.toFile()FileDownloader.downloadCallback.postValue(entity)lastCallback = now}task.addTag(CURRENT_PROGRESS, currentOffset)}override fun connected(task: DownloadTask, blockCount: Int, currentOffset: Long, totalLength: Long) {if (entity.downloadTask == null) {entity.downloadTask = task}entity.currentSize += currentOffsetentity.fileSize += totalLengthentity.toFile()FileDownloader.downloadCallback.postValue(entity)}override fun retry(task: DownloadTask, cause: ResumeFailedCause) {if (entity.downloadTask == null) {entity.downloadTask = task}}})entity.downloadTask = taskdownloadList.add(entity.originalUrl)FileDownloader.addUseProgress(entity.originalUrl)//已使用的线程数增加}
}

多任务管理

以上代码出现了不少的FileDownloader这个类，这个类的主要作用是进行多任务的管理，实现顺序任务下载，限制同时下载数量等功能，具体代码如下：

object FileDownloader {private val TAG = "FileDownloader"val downloadCallback = MutableLiveData<VideoDownloadEntity>()//下载进度回调private var MAX_PROGRESS = -1//最终计算结果至少为1get() {if (field == -1) {field = Runtime.getRuntime().availableProcessors() / 2//可用线程数的一半if (Build.VERSION.SDK_INT < 23) {//如果小于Android6的，可用线程数再减2field -= 2}}if (field > 5) {//最多只能有5个并行field = 5}if (field <= 0) {//最少也要有1个任务field = 1}return field}private var useProgress = 0//已使用的线程数,始终大于0set(value) {if (value >= 0) {field = value}}private var downloadingList = arrayListOf<String>()//下载中的列表，为统计线程使用private var waitDownloadList = arrayListOf<String>()//等待下载的url列表private val downloadList = arrayListOf<VideoDownloadEntity>()//排队列表private val waitList = arrayListOf<VideoDownloadEntity>()//等待下载的队列private var wait = false//m3u8等待状态/*** 停止全部任务*/fun clearAllDownload() {OkDownload.with().downloadDispatcher().cancelAll()downloadingList.clear()waitDownloadList.clear()downloadList.clear()waitList.clear()M3U8ConfigDownloader.clear()M3U8Downloader.clear()SingleVideoDownloader.clear()MAX_PROGRESS = -1useProgress = 0}/*** 减少已使用线程数*/fun subUseProgress(url: String) {if (downloadingList.contains(url)) {useProgress--downloadingList.remove(url)Log.d(TAG, "释放线程---$useProgress")if (downloadList.isNotEmpty()) {Log.d(TAG, "subUseProgress---新增任务")waitDownloadList.removeAt(0)downloadVideo(downloadList.removeAt(0))}}}/*** 增加使用线程数*/fun addUseProgress(url: String) {if (!downloadingList.contains(url)) {useProgress++downloadingList.add(url)}}/*** 获取最顶层的下载目录*/@JvmStaticfun getBaseDownloadPath(): File {val file = File(Environment.getExternalStorageDirectory(), "m3u8Downloader")if (!file.exists()) {file.mkdirs()}return file}/*** 获取根据链接得到的下载存储路径*/@JvmStaticfun getDownloadPath(url: String): File {val file = File(getBaseDownloadPath(), md5(url))if (!file.exists()) {file.mkdir()}return file}/*** 获取相关配置文件*/@JvmStaticfun getConfigFile(url: String): File {val path = getDownloadPath(url)return File(path, "video.config")}/*** 获取相关配置文件*/@JvmStaticfun getConfigFile(path: File): File {return File(path, "video.config")}/*** 下载的入口*/@JvmStaticfun downloadVideo(entity: VideoDownloadEntity) {if (entity.status == DELETE) {return}if (entity.originalUrl.endsWith(".m3u8")) {downloadM3U8File(entity)} else {downloadSingleVideo(entity)}}/*** 下载但文件入口*/@JvmStaticprivate fun downloadSingleVideo(entity: VideoDownloadEntity) {if (entity.status == DELETE) {//删除状态的忽略Log.d(TAG, "downloadSingleVideo---DELETE")return}if (useProgress < MAX_PROGRESS) {//还有可用的线程数SingleVideoDownloader.fileDownloader(entity)//进入下载Log.d(TAG, "-----useProgress===>$useProgress")} else {//没有可用线程的时候就添加到等待队列SingleVideoDownloader.initConfig(entity)//初始化一下下载任务//不是下载中的内容,且没有在等待if (!downloadingList.contains(entity.originalUrl) && !waitDownloadList.contains(entity.originalUrl)) {downloadList.add(entity)waitDownloadList.add(entity.originalUrl)Log.d(TAG, "addDownloadList---${entity.originalUrl}")entity.status = PREPAREdownloadCallback.postValue(entity)} else {if (entity.status == NO_START || entity.status == ERROR || entity.status == PAUSE) {//如果要下载的内容是等待中的，但是状态还没有修正过来，则修正状态entity.status = PREPAREdownloadCallback.postValue(entity)}Log.d(TAG, "下载中或等待中的文件")}}}@JvmStaticprivate fun downloadM3U8File(entity: VideoDownloadEntity) {if (entity.status == DELETE) {//删除状态的忽略Log.d(TAG, "downloadM3U8File---DELETE")return}Log.d(TAG, "$wait--downloadM3U8File--${entity.originalUrl}")thread {if (wait) {//如果有在获取真实ts的内容则添加到等待队列Log.d(TAG, "addWaiting")waitList.add(entity)return@thread}wait = trueval file = M3U8ConfigDownloader.start(entity)//准备下载列表if (useProgress < MAX_PROGRESS) {//还有可用的线程数if (file != null) {//需要下载var times = 50Log.d(TAG, "file.exists()==>${file.exists()}")while (!file.exists() && times > 0) {//如果文件还不存在则等待100msLog.d(TAG, "waiting...")Thread.sleep(100)times--}if (file.exists()) {//如果文件存在了则开始下载M3U8Downloader.bunchDownload(getDownloadPath(entity.originalUrl))}Log.d(TAG, "${file.exists()}-----useProgress===>$useProgress")} else {Log.d(TAG, "file===null")}} else {//没有可用线程的时候就添加到等待队列//不是下载中的内容,且没有在等待if (!downloadingList.contains(entity.originalUrl) &&!waitDownloadList.contains(entity.originalUrl)) {//添加到任务队列downloadList.add(entity)waitDownloadList.add(entity.originalUrl)Log.d(TAG, "addDownloadList---${entity.originalUrl}")entity.status = PREPAREdownloadCallback.postValue(entity)} else {Log.d(TAG, "下载中或等待中的文件")if (entity.status == NO_START || entity.status == ERROR || entity.status == PAUSE) {//如果要下载的内容是等待中的，但是状态还没有修正过来，则修正状态entity.status = PREPAREdownloadCallback.postValue(entity)}}}wait = falseif (waitList.isNotEmpty()) {//有等待获取真实ts流的则继续回调Log.d(TAG, "removeWaiting")downloadM3U8File(waitList.removeAt(0))}}}
}

使用测试

编写完下载库，下面就进行测试了

下载列表的item

具体代码如下：

<?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="wrap_content"android:paddingStart="15dp"android:paddingTop="8dp"android:paddingEnd="15dp"android:paddingBottom="8dp"><TextViewandroid:id="@+id/download"android:layout_width="wrap_content"android:layout_height="wrap_content"android:background="@drawable/shape_download_prepare"android:paddingStart="15dp"android:paddingTop="5dp"android:paddingEnd="15dp"android:paddingBottom="5dp"android:text="@string/btn_download"android:textColor="@color/blue"android:textSize="12sp"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintTop_toTopOf="parent" /><TextViewandroid:id="@+id/title"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginStart="15dp"android:ellipsize="end"android:maxLines="1"android:textSize="18sp"app:layout_constraintEnd_toStartOf="@id/download"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"tools:text="@string/app_name" /><TextViewandroid:id="@+id/current_size"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginTop="5dp"android:textSize="12sp"app:layout_constraintStart_toStartOf="@id/title"app:layout_constraintTop_toBottomOf="@id/title"tools:text="201.37MB" /><TextViewandroid:id="@+id/speed"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginStart="15dp"android:textSize="12sp"app:layout_constraintBottom_toBottomOf="@id/current_size"app:layout_constraintStart_toEndOf="@id/current_size"tools:text="90.5%|251.37kB/s" /><TextViewandroid:id="@+id/url"android:layout_width="0dp"android:layout_height="wrap_content"android:ellipsize="end"android:maxLines="2"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="@id/title"app:layout_constraintTop_toBottomOf="@id/speed"tools:text="https://qq.com-ok-qq.com/20191015/24619_fc6ad1d6/index.m3u8" /></androidx.constraintlayout.widget.ConstraintLayout>

Adapter的编写

class VideoDownloadAdapter(private val list: MutableList<VideoDownloadEntity>) :RecyclerView.Adapter<VideoDownloadAdapter.ViewHolder>() {override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {return ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.item_download_list, parent, false))}override fun getItemCount() = list.size/*** 避免出现整个item闪烁*/override fun onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList<Any>) {if (payloads.isNullOrEmpty()) {super.onBindViewHolder(holder, position, payloads)} else {holder.updateProgress(list[position])}}override fun onBindViewHolder(holder: ViewHolder, position: Int) {holder.setData(list[position])}class ViewHolder(private val view: View) : RecyclerView.ViewHolder(view) {private val title = view.findViewById<TextView>(R.id.title)private val currentSize = view.findViewById<TextView>(R.id.current_size)private val speed = view.findViewById<TextView>(R.id.speed)private val url = view.findViewById<TextView>(R.id.url)private val download = view.findViewById<TextView>(R.id.download)/*** 设置数据*/@SuppressLint("SetTextI18n")fun setData(data: VideoDownloadEntity?) {if (data == null) {return}val context = view.contexturl.text = data.originalUrlval name = if (data.name.isNotEmpty()) {if (data.subName.isNotEmpty()) {"${data.name}(${data.subName})"} else {data.name}} else {if (data.subName.isNotEmpty()) {"${context.getString(R.string.unknow_movie)}(${data.subName})"} else {context.getString(R.string.unknow_movie)}}title.text = nameupdateProgress(data)}/*** 进度更新*/@SuppressLint("SetTextI18n")fun updateProgress(data: VideoDownloadEntity) {if (data.originalUrl.endsWith(".m3u8") || data.status == COMPLETE) {currentSize.text =getSizeUnit(data.currentSize.toDouble())} else {currentSize.text ="${getSizeUnit(data.currentSize.toDouble())}/${getSizeUnit(data.fileSize.toDouble())}"}speed.text ="${DecimalFormat("#.##%").format(data.currentProgress)}|${data.currentSpeed}"val context = view.context//状态逻辑处理when (data.status) {NO_START -> {download.setTextColor(ContextCompat.getColor(context, R.color.blue))download.background =ContextCompat.getDrawable(context, R.drawable.shape_download_prepare)download.setText(R.string.btn_download)download.isVisible = truespeed.isVisible = falsecurrentSize.isVisible = falsecurrentSize.setText(R.string.wait_download)download.setOnClickListener {if (data.startDownload != null) {data.startDownload!!.invoke()} else {FileDownloader.downloadVideo(data)}}}DOWNLOADING -> {currentSize.isVisible = truespeed.isVisible = truespeed.setTextColor(ContextCompat.getColor(speed.context, R.color.blue))download.isVisible = truedownload.setText(R.string.pause)download.setOnClickListener {data.downloadContext?.stop()data.downloadTask?.cancel()}download.setTextColor(ContextCompat.getColor(context, R.color.white))download.background =ContextCompat.getDrawable(context, R.drawable.shape_blue_btn)}PAUSE -> {currentSize.isVisible = truedownload.setTextColor(ContextCompat.getColor(context, R.color.white))download.background =ContextCompat.getDrawable(context, R.drawable.shape_blue_btn)download.isVisible = truedownload.setText(R.string.go_on)download.setOnClickListener {if (data.startDownload != null) {data.startDownload!!.invoke()} else {FileDownloader.downloadVideo(data)}}speed.isVisible = truespeed.setText(R.string.already_paused)speed.setTextColor(ContextCompat.getColor(speed.context, R.color.red))}COMPLETE -> {currentSize.isVisible = truedownload.isVisible = falsespeed.isVisible = false}PREPARE -> {currentSize.isVisible = truedownload.setText(R.string.prepareing)currentSize.setText(R.string.wait_download)download.isVisible = truedownload.setOnClickListener {if (data.startDownload != null) {data.startDownload!!.invoke()} else {FileDownloader.downloadVideo(data)}}download.setTextColor(ContextCompat.getColor(context, R.color.blue))download.background =ContextCompat.getDrawable(context, R.drawable.shape_download_prepare)speed.isVisible = false}ERROR -> {currentSize.isVisible = falsespeed.isVisible = falsedownload.isVisible = truedownload.setText(R.string.retry)download.setOnClickListener {if (data.startDownload != null) {data.startDownload!!.invoke()} else {FileDownloader.downloadVideo(data)}}download.setTextColor(ContextCompat.getColor(context, R.color.white))download.background =ContextCompat.getDrawable(context, R.drawable.shape_blue_btn)}}}}}

由于是下载列表，如果频繁刷新是会导致整个item不断闪烁的，所以在下载库那边也有处理了1秒钟才发出一次进度更新，而在接收的时候一定要注意，需要重写onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList<Any>)这个函数，通知adapter更新的时候应该调用notifyItemChanged(int position, @Nullable Object payload)这样可以避免整个item闪烁，实现只更新局部控件的效果

Activity的实现

@RuntimePermissions
class MainActivity : AppCompatActivity() {private lateinit var adapter: VideoDownloadAdapterprivate val videoList = arrayListOf<VideoDownloadEntity>()private val tempList = arrayListOf<String>()private val gson = GsonBuilder().create()override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)initListView()initListWithPermissionCheck()//接收进度通知FileDownloader.downloadCallback.observe(this, Observer {onProgress(it)})//新建下载add.setOnClickListener {newDownload()}}private fun initListView() {adapter = VideoDownloadAdapter(videoList)list.adapter = adapter}@NeedsPermission(Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE)fun initList() {thread {//在线程中处理，防止ANRFileDownloader.getBaseDownloadPath().listFiles().forEach {val file = File(it, "video.config")if (file.exists()) {val text = file.readText()if (text.isNotEmpty()) {val data = gson.fromJson<VideoDownloadEntity>(text,VideoDownloadEntity::class.java)if (data != null) {if (data.status == DELETE) {it.deleteRecursively()} else if (!tempList.contains(data.originalUrl)) {videoList.add(data)tempList.add(data.originalUrl)}}}}}runOnUiThread {//主线程通知刷新布局adapter.notifyDataSetChanged()}videoList.sort()//依次添加下载队列videoList.filter { it.status == DOWNLOADING }.forEach {FileDownloader.downloadVideo(it)}videoList.filter { it.status == PREPARE }.forEach {FileDownloader.downloadVideo(it)}videoList.filter { it.status == NO_START }.forEach {FileDownloader.downloadVideo(it)}}}@OnPermissionDenied(Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE)fun onDenied() {toast(R.string.need_permission_tips)}private fun toast(@StringRes msg: Int) {Toast.makeText(this, msg, Toast.LENGTH_LONG).show()}override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {super.onRequestPermissionsResult(requestCode, permissions, grantResults)onRequestPermissionsResult(requestCode, grantResults)}private fun onProgress(entity: VideoDownloadEntity) {for ((index, item) in videoList.withIndex()) {if (item.originalUrl == entity.originalUrl) {videoList[index].status = entity.statusvideoList[index].currentSize = entity.currentSizevideoList[index].currentSpeed = entity.currentSpeedvideoList[index].currentProgress = entity.currentProgressvideoList[index].fileSize = entity.fileSizevideoList[index].tsSize = entity.tsSizevideoList[index].downloadContext = entity.downloadContextvideoList[index].downloadTask = entity.downloadTaskvideoList[index].startDownload = entity.startDownloadadapter.notifyItemChanged(index, 0)break}}}private fun newDownload() {val editText = EditText(this)editText.setHint(R.string.please_input_download_address)val downloadDialog = AlertDialog.Builder(this).setView(editText).setTitle(R.string.new_download).setPositiveButton(R.string.ok) { dialog, _ ->if (editText.text.isNullOrEmpty()) {toast(R.string.please_input_download_address)return@setPositiveButton}val url = editText.text.toString()if (tempList.contains(url)) {toast(R.string.already_download)dialog.dismiss()return@setPositiveButton}val name = if (url.contains("?")) {url.substring(url.lastIndexOf("/") + 1, url.indexOf("?"))} else {url.substring(url.lastIndexOf("/") + 1)}val entity = VideoDownloadEntity(url, name)entity.toFile()videoList.add(0, entity)adapter.notifyItemInserted(0)FileDownloader.downloadVideo(entity)}.setNegativeButton(R.string.cancle) { dialog, _ ->dialog.dismiss()}.create()downloadDialog.show()}
}