通话中切换扬声器流程

切换流程将从这里的onclick事件开始分析：回头CallButtonFragment

    public void onClick(View view) {
        int id = view.getId();
        int mode = AudioState.ROUTE_WIRED_OR_EARPIECE;
        Log.d(this, "onClick(View " + view + ", id " + id + ")...");

        switch(id) {
            case R.id.audioButton:
                onAudioButtonClicked();

}

    private void onAudioButtonClicked() {
        if (isSupported(AudioState.ROUTE_BLUETOOTH)) {
            showAudioModePopup();
        } else {
            getPresenter().toggleSpeakerphone();
        }
    }

CallButtonPresenter.java

    public void toggleSpeakerphone() {
        setAudioMode(newMode);
    }

    public void setAudioMode(int mode) {
        TelecomAdapter.getInstance().setAudioRoute(mode);
    }
Phone.java

    public final void setAudioRoute(int route) {
        mInCallAdapter.setAudioRoute(route);
    }

InCallAdapter.java

    public void setAudioRoute(int route) {
        mHandler.obtainMessage(MSG_SET_AUDIO_ROUTE, route, 0).sendToTarget();
    }

    private final class InCallAdapterHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
           case MSG_SET_AUDIO_ROUTE:
                    mCallsManager.setAudioRoute(msg.arg1);
                    break;

}

CallsManager.java

    void setAudioRoute(int route) {
        mCallAudioManager.setAudioRoute(route);
    }

ok, 经过系列转换，终于见到曙光了。

CallAudioManager.java

void setAudioRoute(int route) {

setSystemAudioState(mAudioState.isMuted(), newRoute,
                    mAudioState.getSupportedRouteMask());

}

    private void turnOnSpeaker(boolean on) {
        // Wired headset and earpiece work the same way
        if (mAudioManager.isSpeakerphoneOn() != on) {
            Log.i(this, "turning speaker phone %s", on);
            mAudioManager.setSpeakerphoneOn(on);
        }
    }

终于调用到AudioManager.  这才是系统提供的api。

audiomanager 通过binder 机制调用Audioservice。省去中间简单传递过程，直接从audioservice分析

        private void setForceUse(int usage, int config) {
            AudioSystem.setForceUse(usage, config);
        }

通过audiosystem 以jni 机制调用native方法。 android_media_AudioSystem.cpp

static jint
android_media_AudioSystem_setForceUse(JNIEnv *env, jobject thiz, jint usage, jint config)
{
    return (jint) check_AudioSystem_Command(AudioSystem::setForceUse(static_cast (usage),
                                                           static_cast (config)));
}

AudioSystem.cpp

status_t AudioSystem::setForceUse(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config)
{
    const sp& aps = AudioSystem::get_audio_policy_service();
    if (aps == 0) return PERMISSION_DENIED;
    return aps->setForceUse(usage, config);
}

IAudioPolicyService.cpp

    virtual status_t setForceUse(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config)
    {
        Parcel data, reply;
        data.writeInterfaceToken(IAudioPolicyService::getInterfaceDescriptor());
        data.writeInt32(static_cast (usage));
        data.writeInt32(static_cast (config));
        remote()->transact(SET_FORCE_USE, data, &reply);
        return static_cast (reply.readInt32());
    }

AudioPolicyInterfaceImpl.cpp

status_t AudioPolicyService::setForceUse(audio_policy_force_use_t usage,
                                         audio_policy_forced_cfg_t config)
{
 
    Mutex::Autolock _l(mLock);
    mAudioPolicyManager->setForceUse(usage, config);
    return NO_ERROR;
}
AudioPolicyManager.cpp
void AudioPolicyManager::setForceUse(audio_policy_force_use_t usage,
                                         audio_policy_forced_cfg_t config)
{

applyStreamVolumes(output, newDevice, 0, true);

}

void AudioPolicyManager::applyStreamVolumes(audio_io_handle_t output,
                                                audio_devices_t device,
                                                int delayMs,
                                                bool force)
{

        checkAndSetVolume((audio_stream_type_t)stream,
                          mStreams[stream].getVolumeIndex(device),
                          output,
                          device,
                          delayMs,
                          force);
    }
}

status_t AudioPolicyManager::checkAndSetVolume(audio_stream_type_t stream,
                                                   int index,
                                                   audio_io_handle_t output,
                                                   audio_devices_t device,
                                                   int delayMs,
                                                   bool force)
{

}

后续基本流程

AudioPolicyClientImpl.cpp

AudioPolicyService.cpp

AudioFlinger.cpp