ExoPlayer播放本地已存在文件时偶发FileNotFoundException问题

架构老林

2026-7-23

问题：ExoPlayer播放DownloadManager下载的视频时出现FileNotFoundException（文件实际存在）

环境与实现逻辑

使用androidx.media3:media3-exoplayer:1.0.1
通过Android DownloadManager将视频下载到公共Download文件夹，文件名使用后端返回的UUID
播放时通过UUID匹配对应的视频URI，使用ExoPlayer播放

ViewModel下载触发代码

private fun downloadVideos() {
        viewModelScope.launch {
            mediaRepository.getMediaItems().forEach { item ->
                downloader.downloadFile(item.uuid, item.filePath)
            }
        }
    }

Downloader实现类

class AndroidDownloader(
    context: Context
): Downloader {

    private val downloadManager = context.getSystemService(DownloadManager::class.java)

    override fun downloadFile(title: String, url: String): Long {
        val request = DownloadManager.Request(url.toUri())
            .setMimeType("video/mp4")
            .setNotificationVisibility(
                DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED
                    or DownloadManager.Request.VISIBILITY_VISIBLE
            )
            .setTitle(title)
            .setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, title)
        return downloadManager.enqueue(request)
    }
}

播放触发逻辑（ViewModel）

override fun playVideo(uuid: String) {
        videoIsPlaying = true
        currentUri = fileParser.getUri(uuid)
        currentUri?.let {
            viewModelScope.launch {
                videoPlayer.playVideo(it)
            }
        }
    }

FileParser（根据UUID获取URI）

class FileParser(private val context: Context, private val pref: DefaultSharedPref) {

    private val listOfUris = mutableListOf<Uri>()

    fun getUri(uuid: String) : Uri? {
        if (listOfUris.isEmpty()) {
            val manager: DownloadManager =
                context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager

            pref.getVideoIds().forEach {
                val uri = manager.getUriForDownloadedFile(it.toLong())
                uri.path?.let {
                    listOfUris.add(uri)
                }
            }
        }
        listOfUris.forEach {
            val fileName = context.getFileName(it)
            if (fileName == uuid)
                return it
        }
        return null
    }
}

fun Context.getFileName(uri: Uri): String? = when(uri.scheme) {
    ContentResolver.SCHEME_CONTENT -> getContentFileName(uri)
    else -> uri.path?.let(::File)?.name
}

private fun Context.getContentFileName(uri: Uri): String? = runCatching {
    contentResolver.query(uri, null, null, null, null)?.use { cursor ->
        cursor.moveToFirst()
        return@use cursor.getColumnIndexOrThrow(OpenableColumns.DISPLAY_NAME).let(cursor::getString)
    }
}.getOrNull()

ExoPlayer播放实现

fun playVideo(uri: Uri) {
        player.setMediaItem(MediaItem.fromUri(uri))
        player.prepare()
        player.play()
    }

Jetpack Compose UI代码

AnimatedVisibility(visible = videoIsPlaying) {
            AndroidView(
                factory = { context ->
                    PlayerView(context).also {
                        it.resizeMode = AspectRatioFrameLayout.RESIZE_MODE_FILL
                        it.useController = false
                        it.player = videoPlayer.player
                    }
                },
                update = {
                    when (lifecycle) {
                        Lifecycle.Event.ON_PAUSE -> {
                            it.onPause()
                            it.player?.pause()
                        }
                        Lifecycle.Event.ON_RESUME -> {
                            it.onResume()
                        }
                        else -> Unit
                    }
                },
                modifier = Modifier
                    .fillMaxHeight()
                    .aspectRatio(16 / 9f)
            )
        }

问题现象

视频可正常播放数小时/数分钟，但一段时间后抛出以下异常：

Playback error androidx.media3.exoplayer.ExoPlaybackException: Source error
at androidx.media3.exoplayer.ExoPlayerImplInternal.handleIoException(ExoPlayerImplInternal.java:652)
at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:624)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.HandlerThread.run(HandlerThread.java:67)
Caused by: androidx.media3.datasource.ContentDataSource$ContentDataSourceException: java.io.FileNotFoundException: open failed: ENOENT (No such file or directory)
at androidx.media3.datasource.ContentDataSource.open(ContentDataSource.java:157)
at androidx.media3.datasource.DefaultDataSource.open(DefaultDataSource.java:272)
at androidx.media3.datasource.StatsDataSource.open(StatsDataSource.java:86)
at androidx.media3.exoplayer.source.ProgressiveMediaPeriod$ExtractingLoadable.load(ProgressiveMediaPeriod.java:1006)
at androidx.media3.exoplayer.upstream.Loader$LoadTask.run(Loader.java:414)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1137)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:637)
at java.lang.Thread.run(Thread.java:1012)
Caused by: java.io.FileNotFoundException: open failed: ENOENT (No such file or directory)
at android.database.DatabaseUtils.readExceptionWithFileNotFoundExceptionFromParcel(DatabaseUtils.java:151)
at android.content.ContentProviderProxy.openTypedAssetFile(ContentProviderNative.java:780)
at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:2029)
at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:1967)
at androidx.media3.datasource.ContentDataSource.open(ContentDataSource.java:89)
at androidx.media3.datasource.DefaultDataSource.open(DefaultDataSource.java:272) 
at androidx.media3.datasource.StatsDataSource.open(StatsDataSource.java:86) 
at androidx.media3.exoplayer.source.ProgressiveMediaPeriod$ExtractingLoadable.load(ProgressiveMediaPeriod.java:1006) 
at androidx.media3.exoplayer.upstream.Loader$LoadTask.run(Loader.java:414) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1137) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:637) 
at java.lang.Thread.run(Thread.java:1012)

此时文件实际仍存在且文件名未修改
首次触发异常后视频无法再播放，仅能通过卸载重装应用或清理缓存临时解决，一段时间后问题复发
已尝试的无效方案：
- 使用DefaultDataSource自定义数据源工厂
- 添加seekTo(0)重启视频
- 添加文件访问权限

问题分析与解决方案

核心原因

DownloadManager的Content URI失效：content://downloads/all_downloads/xxx这类URI依赖系统DownloadProvider的数据库记录，系统清理（媒体库扫描、Provider缓存失效、系统优化）会导致记录丢失，使URI无法访问实际文件。
URI缓存机制缺陷：listOfUris仅首次初始化，后续不会更新，即使原URI失效也持续使用。
公共目录访问稳定性差：公共Download文件夹的文件可能被其他应用/系统修改，Content URI访问依赖系统Provider状态，稳定性不如直接访问文件路径。

解决方案

方案1：改用FileProvider URI直接访问文件路径

这是最稳定的方案，避免依赖DownloadProvider的数据库状态：

修改Downloader，保存文件绝对路径到SharedPreferences：

class AndroidDownloader(
    context: Context,
    private val pref: DefaultSharedPref
): Downloader {

    private val downloadManager = context.getSystemService(DownloadManager::class.java)

    override fun downloadFile(title: String, url: String): Long {
        val file = File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), title)
        val request = DownloadManager.Request(url.toUri())
            .setMimeType("video/mp4")
            .setNotificationVisibility(
                DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED
                    or DownloadManager.Request.VISIBILITY_VISIBLE
            )
            .setTitle(title)
            .setDestinationUri(Uri.fromFile(file))
        
        val downloadId = downloadManager.enqueue(request)
        pref.saveVideoPath(title, file.absolutePath)
        return downloadId
    }
}

修改FileParser，通过路径生成FileProvider URI：

class FileParser(private val context: Context, private val pref: DefaultSharedPref) {

    fun getUri(uuid: String) : Uri? {
        val filePath = pref.getVideoPath(uuid) ?: return null
        val file = File(filePath)
        return if (file.exists()) {
            FileProvider.getUriForFile(context, "${context.packageName}.fileprovider", file)
        } else null
    }
}

需在Manifest中配置FileProvider：

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="${applicationId}.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

并在res/xml/file_paths.xml中添加：

<paths>
    <external-path name="downloads" path="Download/" />
</paths>

方案2：修复URI缓存与有效性校验

每次获取URI时重新校验有效性，避免使用失效URI：

class FileParser(private val context: Context, private val pref: DefaultSharedPref) {

    fun getUri(uuid: String) : Uri? {
        val manager: DownloadManager =
            context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager

        pref.getVideoIds().forEach { downloadId ->
            val uri = manager.getUriForDownloadedFile(downloadId.toLong()) ?: continue
            val fileName = context.getFileName(uri)
            if (fileName == uuid && isUriValid(context, uri)) {
                return uri
            }
        }
        return null
    }

    private fun isUriValid(context: Context, uri: Uri): Boolean {
        return runCatching {
            context.contentResolver.openInputStream(uri)?.use { true } ?: false
        }.getOrDefault(false)
    }
}

方案3：监听DownloadProvider变化更新缓存

注册ContentObserver，当DownloadProvider数据变化时清空缓存：

class FileParser(private val context: Context, private val pref: DefaultSharedPref) {

    private val listOfUris = mutableListOf<Uri>()
    private val observer = object : ContentObserver(Handler(Looper.getMainLooper())) {
        override fun onChange(selfChange: Boolean) {
            super.onChange(selfChange)
            listOfUris.clear()
        }
    }

    init {
        context.contentResolver.registerContentObserver(
            Uri.parse("content://downloads/all_downloads"),
            true,
            observer
        )
    }

    fun destroy() {
        context.contentResolver.unregisterContentObserver(observer)
    }

    // 原getUri方法保持不变
}

总结

优先选择方案1，直接通过文件路径生成FileProvider URI，彻底规避DownloadProvider的稳定性问题，同时简化逻辑，减少系统依赖引发的异常。

内容的提问来源于stack exchange，提问作者Andrii

ExoPlayer播放本地已存在文件时偶发FileNotFoundException问题

环境与实现逻辑 #

ViewModel下载触发代码 #

Downloader实现类 #

播放触发逻辑（ViewModel） #

FileParser（根据UUID获取URI） #

ExoPlayer播放实现 #

Jetpack Compose UI代码 #

问题现象 #

问题分析与解决方案 #

核心原因 #

解决方案 #