Android 单一音量控制

1、关闭/开启单一音量控制

frameworks/base/core/res/res/values/config.xml

html 复制代码
    <!-- Flag indicating whether all audio streams should be mapped to
         one single stream. If true, all audio streams are mapped to
         STREAM_MUSIC as if it's on TV platform. -->
    <bool name="config_single_volume">false</bool>

开启单一音量控制后,系统音量控制将直接跟随媒体音量,由其单一控制;

2、单一音量控制流程解析

frameworks/base/media/java/android/media/AudioSystem.java

java 复制代码
    /**
     * @hide
     * @return whether the system uses a single volume stream.
     */
    public static boolean isSingleVolume(Context context) {
        boolean forceSingleVolume = context.getResources().getBoolean(
                com.android.internal.R.bool.config_single_volume);
        return getPlatformType(context) == PLATFORM_TELEVISION || forceSingleVolume;
    }

frameworks/base/services/core/java/com/android/server/audio/AudioService.java

java 复制代码
mIsSingleVolume = AudioSystem.isSingleVolume(context);

...

    private void updateStreamVolumeAlias(boolean updateVolumes, String caller) {
        int dtmfStreamAlias;
        final int a11yStreamAlias = sIndependentA11yVolume ?
                AudioSystem.STREAM_ACCESSIBILITY : AudioSystem.STREAM_MUSIC;

        if (mIsSingleVolume) {
            mStreamVolumeAlias = STREAM_VOLUME_ALIAS_TELEVISION;
            dtmfStreamAlias = AudioSystem.STREAM_MUSIC;
        } else {
            switch (mPlatformType) {
                case AudioSystem.PLATFORM_VOICE:
                    mStreamVolumeAlias = STREAM_VOLUME_ALIAS_VOICE;
                    dtmfStreamAlias = AudioSystem.STREAM_RING;
                    break;
                default:
                    mStreamVolumeAlias = STREAM_VOLUME_ALIAS_DEFAULT;
                    dtmfStreamAlias = AudioSystem.STREAM_MUSIC;
            }
        }

        if (mIsSingleVolume) {
            mRingerModeAffectedStreams = 0;
        } else {
            if (isInCommunication()) {
                dtmfStreamAlias = AudioSystem.STREAM_VOICE_CALL;
                mRingerModeAffectedStreams &= ~(1 << AudioSystem.STREAM_DTMF);
            } else {
                mRingerModeAffectedStreams |= (1 << AudioSystem.STREAM_DTMF);
            }
        }
java 复制代码
    private final int[] STREAM_VOLUME_ALIAS_TELEVISION = new int[] {
        AudioSystem.STREAM_MUSIC,       // STREAM_VOICE_CALL
        AudioSystem.STREAM_MUSIC,       // STREAM_SYSTEM
        AudioSystem.STREAM_MUSIC,       // STREAM_RING
        AudioSystem.STREAM_MUSIC,       // STREAM_MUSIC
        AudioSystem.STREAM_MUSIC,       // STREAM_ALARM
        AudioSystem.STREAM_MUSIC,       // STREAM_NOTIFICATION
        AudioSystem.STREAM_MUSIC,       // STREAM_BLUETOOTH_SCO
        AudioSystem.STREAM_MUSIC,       // STREAM_SYSTEM_ENFORCED
        AudioSystem.STREAM_MUSIC,       // STREAM_DTMF
        AudioSystem.STREAM_MUSIC,       // STREAM_TTS
        AudioSystem.STREAM_MUSIC        // STREAM_ACCESSIBILITY
    };
    private final int[] STREAM_VOLUME_ALIAS_DEFAULT = new int[] {
        AudioSystem.STREAM_VOICE_CALL,      // STREAM_VOICE_CALL
        AudioSystem.STREAM_RING,            // STREAM_SYSTEM
        AudioSystem.STREAM_RING,            // STREAM_RING
        AudioSystem.STREAM_MUSIC,           // STREAM_MUSIC
        AudioSystem.STREAM_ALARM,           // STREAM_ALARM
        AudioSystem.STREAM_RING,            // STREAM_NOTIFICATION
        AudioSystem.STREAM_BLUETOOTH_SCO,   // STREAM_BLUETOOTH_SCO
        AudioSystem.STREAM_RING,            // STREAM_SYSTEM_ENFORCED
        AudioSystem.STREAM_RING,            // STREAM_DTMF
        AudioSystem.STREAM_MUSIC,           // STREAM_TTS
        AudioSystem.STREAM_MUSIC            // STREAM_ACCESSIBILITY
    };

AudioService获取到单一音量控制状态后,根据映射来更新系统不同音频流的音量;

相关推荐
跟着珅聪学java2 小时前
spring boot 整合 activiti 教程
android·java·spring
junnhwan3 小时前
【苍穹外卖笔记】Day04--套餐管理模块
java·数据库·spring boot·后端·苍穹外卖·crud
川石课堂软件测试4 小时前
全链路Controller压测负载均衡
android·运维·开发语言·python·mysql·adb·负载均衡
程序员清风4 小时前
Dubbo RPCContext存储一些通用数据,这个用手动清除吗?
java·后端·面试
摇滚侠4 小时前
Spring Boot 3零基础教程,条件注解,笔记09
java·spring boot·笔记
南瓜小米粥、4 小时前
从可插拔拦截器出发:自定义、注入 Spring Boot、到生效路径的完整实践(Demo 版)
java·spring boot·后端
Huangmiemei9114 小时前
Spring Boot项目的常用依赖有哪些?
java·spring boot·后端
天天摸鱼的java工程师4 小时前
接口联调总卡壳?先问自己:真的搞清楚 HTTP 的 Header 和 Body 了吗?
java·后端
真的想不出名儿4 小时前
上传头像到腾讯云对象存储-前端基于antdv
java·数据库·腾讯云
Nan_Shu_6144 小时前
学习SpringBoot
java·spring boot·后端·学习·spring