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

    <!-- 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

    /**
     * @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 || f