Android应用恢复视频时ExoPlayer音频焦点丢失的处理方案

针对你遇到的恢复播放后短暂停止、提示PLAY_WHEN_READY_CHANGE_REASON_AUDIO_FOCUS_LOSS的问题，以下是具体的修复建议：

1. 优化音频焦点请求逻辑 #

不要在恢复播放时直接调用player.play()，而是先主动请求音频焦点，且使用永久获取的类型（AUDIOFOCUS_GAIN），确保系统明确分配焦点到你的应用：

private val audioManager by lazy { getSystemService(Context.AUDIO_SERVICE) as AudioManager }
private val audioFocusRequest by lazy {
    AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
        .setOnAudioFocusChangeListener { focusChange ->
            handleAudioFocusChange(focusChange)
        }
        .setAudioAttributes(
            AudioAttributes.Builder()
                .setUsage(AudioAttributes.USAGE_MEDIA)
                .setContentType(AudioAttributes.CONTENT_TYPE_MOVIE)
                .build()
        )
        .build()
}

// 恢复播放前先请求焦点
fun resumePlayer() {
    val focusResult = audioManager.requestAudioFocus(audioFocusRequest)
    if (focusResult == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
        player.play()
    }
}

2. 精准处理音频焦点状态变化 #

在焦点回调中，区分临时丢失和永久丢失，避免误暂停；同时在重新获得焦点时，确保只有当播放器是因焦点丢失而暂停的情况下才恢复：

private var wasPausedByAudioFocusLoss = false

private fun handleAudioFocusChange(focusChange: Int) {
    when (focusChange) {
        AudioManager.AUDIOFOCUS_LOSS -> {
            // 永久丢失焦点，彻底暂停并标记状态
            wasPausedByAudioFocusLoss = true
            player.pause()
        }
        AudioManager.AUDIOFOCUS_LOSS_TRANSIENT, AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK -> {
            // 临时丢失焦点，暂停但保留播放状态
            wasPausedByAudioFocusLoss = true
            player.pause()
        }
        AudioManager.AUDIOFOCUS_GAIN -> {
            // 重新获得焦点，且之前是因焦点丢失暂停的，才恢复播放
            if (wasPausedByAudioFocusLoss) {
                player.play()
                wasPausedByAudioFocusLoss = false
            }
        }
    }
}

3. 结合应用生命周期调整焦点管理 #

在应用从后台返回前台（onResume）时，不要直接恢复播放，而是先检查当前音频焦点状态，必要时重新请求：

override fun onResume() {
    super.onResume()
    // 检查当前是否持有音频焦点
    val currentFocusStatus = audioManager.getAudioFocusRequest(audioFocusRequest)
    if (currentFocusStatus != AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
        // 重新请求焦点后再恢复
        resumePlayer()
    } else {
        // 已持有焦点，直接恢复播放
        player.play()
    }
}

override fun onPause() {
    super.onPause()
    // 后台时放弃焦点，避免干扰其他应用
    audioManager.abandonAudioFocusRequest(audioFocusRequest)
}

4. 处理第三方应用焦点残留问题 #

部分浏览器或视频应用暂停后可能未正确释放音频焦点，导致系统焦点状态延迟更新。可以在恢复播放前添加短暂延迟，或重复请求焦点：

fun resumePlayerWithRetry() {
    Handler(Looper.getMainLooper()).postDelayed({
        val focusResult = audioManager.requestAudioFocus(audioFocusRequest)
        if (focusResult == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
            player.play()
        } else {
            // 重试一次，适配焦点状态延迟更新的情况
            Handler(Looper.getMainLooper()).postDelayed({
                if (audioManager.requestAudioFocus(audioFocusRequest) == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
                    player.play()
                }
            }, 500)
        }
    }, 300)
}

5. 统一ExoPlayer音频属性配置 #

确保ExoPlayer使用的音频属性与焦点请求一致，避免系统因属性不匹配收回焦点：

val audioAttributes = AudioAttributes.Builder()
    .setUsage(AudioAttributes.USAGE_MEDIA)
    .setContentType(AudioAttributes.CONTENT_TYPE_MOVIE)
    .build()
player.setAudioAttributes(audioAttributes, true)

内容的提问来源于stack exchange，提问作者Giru Bhai