Camera拍照声设定

    case STRATEGY_ENFORCED_AUDIBLE:
        // strategy STRATEGY_ENFORCED_AUDIBLE uses same routing policy as STRATEGY_SONIFICATION
        // except:
        //   - when in call where it doesn‘t default to STRATEGY_PHONE behavior
        //   - in countries where not enforced in which case it follows STRATEGY_MEDIA

        if ((strategy == STRATEGY_SONIFICATION) ||
                (mForceUse[AudioSystem::FOR_SYSTEM] == AudioSystem::FORCE_SYSTEM_ENFORCED)) {
            device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_SPEAKER;
            if (device == AUDIO_DEVICE_NONE) {
                ALOGE("getDeviceForStrategy() speaker device not found for STRATEGY_SONIFICATION");
            }
        }
        // The second device used for sonification is the same as the device used by media strategy
        // FALL THROUGH

    case STRATEGY_MEDIA: {
        uint32_t device2 = AUDIO_DEVICE_NONE;
        if (strategy != STRATEGY_SONIFICATION) {
            // no sonification on remote submix (e.g. WFD)
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_REMOTE_SUBMIX;
        }
        if ((device2 == AUDIO_DEVICE_NONE) &&
                mHasA2dp && (mForceUse[AudioSystem::FOR_MEDIA] != AudioSystem::FORCE_NO_BT_A2DP) &&
                (getA2dpOutput() != 0) && !mA2dpSuspended) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP;
            if (device2 == AUDIO_DEVICE_NONE) {
                device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES;
            }
            if (device2 == AUDIO_DEVICE_NONE) {
                device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER;
            }
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_WIRED_HEADPHONE;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_WIRED_HEADSET;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_USB_ACCESSORY;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_USB_DEVICE;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET;
        }
        if ((device2 == AUDIO_DEVICE_NONE) && (strategy != STRATEGY_SONIFICATION)) {
            // no sonification on aux digital (e.g. HDMI)
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_AUX_DIGITAL;
        }
        if ((device2 == AUDIO_DEVICE_NONE) &&
                (mForceUse[AudioSystem::FOR_DOCK] == AudioSystem::FORCE_ANALOG_DOCK)) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = mAvailableOutputDevices & AUDIO_DEVICE_OUT_SPEAKER;
        }

        // device is DEVICE_OUT_SPEAKER if we come from case STRATEGY_SONIFICATION or
        // STRATEGY_ENFORCED_AUDIBLE, AUDIO_DEVICE_NONE otherwise
        device |= device2;
        if (device) break;
        device = mDefaultOutputDevice;
        if (device == AUDIO_DEVICE_NONE) {
            ALOGE("getDeviceForStrategy() no device found for STRATEGY_MEDIA");
        }
        } break;

    boolean cameraSoundForced = mContext.getResources().getBoolean(
                com.android.internal.R.bool.config_camera_sound_forced);
    mCameraSoundForced = new Boolean(cameraSoundForced);
    sendMsg(mAudioHandler,
            MSG_SET_FORCE_USE,
            SENDMSG_QUEUE,
            AudioSystem.FOR_SYSTEM,
            cameraSoundForced ?
                      AudioSystem.FORCE_SYSTEM_ENFORCED :AudioSystem.FORCE_NONE,
            null,
            0);