|
1.systemserver.java 2.android_server_SystemServer_init1.cpp 3.System_init.cpp 4.systemserver.java 新建线程 class ServerThread extends Thread { …… public void run() { …… try { Log.i(TAG, "Headset Observer"); // Listen for wired headset changes headset = new HeadsetObserver(context); // new a thread to observer headset status } catch (Throwable e) { Log.e(TAG, "Failure starting HeadsetObserver", e); } } }
5.启动服务并广播：HeadsetObserver.java class HeadsetObserver extends UeventObserver { …… public HeadsetObserver(Context context) { …… startObserving(HEADSET_UEVENT_MATCH); init(); // set initial status } }
6.AudioService.java中将接收广播 private class AudioServiceBroadcastReceiver extends BroadcastReceiver { public void onReceive(Context context, Intent intent) { …… else if (action.equals(Intent.ACTION_HEADSET_PLUG)) { …… //if you first insert headset, will implement fellow code AudioSystem.setDeviceConnectionState(AudioSystem.DEVICE_OUT_WIRED_HEADSET,AudioSystem.DEVICE_STATE_AVAILABLE,""); } } }
7.设置设备连接1：状态android_media_AudioSystem.cpp static JNINativeMethod gMethods[] = { "setDeviceConnectionState","(IILjava/lang/String;)I",(void*)android_media_AudioSystem_setDeviceConnectionState}, };
8.设置连接状态2：AudioSystem.cpp status_t AudioSystem::setDeviceConnectionState(audio_devices device, device_connection_state state, const char *device_address) { const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service(); if (aps == 0) return PERMISSION_DENIED; return aps->setDeviceConnectionState(device, state, device_address); } 9.设置连接状态3：AudioPolicyManager.cpp status_t AudioPolicyManager::setDeviceConnectionState(AudioSystem::audio_devices device, AudioSystem::device_connection_state state, const char *device_address) { …… // handle output devices if (AudioSystem::isOutputDevice(device)) { switch (state) { case AudioSystem::DEVICE_STATE_AVAILABLE: …… if (AudioSystem::isBluetoothScoDevice(device)) { …… } else if (device == AudioSystem::DEVICE_OUT_WIRED_HEADSET || device == AudioSystem::DEVICE_OUT_WIRED_HEADPHONE) { if (getDeviceForStrategy(STRATEGY_PHONE) == device && (mPhoneState == AudioSystem::MODE_IN_CALL || mOutputs.valueFor(mHardwareOutput)->isUsedByStrategy(STRATEGY_PHONE))) { newDevice = device; } else if ((getDeviceForStrategy(STRATEGY_SONIFICATION) & device) && mOutputs.valueFor(mHardwareOutput)->isUsedByStrategy(STRATEGY_SONIFICATION)) { newDevice = getDeviceForStrategy(STRATEGY_SONIFICATION); } else if ((getDeviceForStrategy(STRATEGY_MEDIA) == device) && mOutputs.valueFor(mHardwareOutput)->isUsedByStrategy(STRATEGY_MEDIA)) { newDevice = device; } else if (getDeviceForStrategy(STRATEGY_DTMF) == device && mOutputs.valueFor(mHardwareOutput)->isUsedByStrategy(STRATEGY_DTMF)) { newDevice = device; } } } }
10.确定输出设备AudioPolicyManager.cpp setOutputDevice(mHardwareOutput, newDevice);
11.最后通过alsa切换通路输出 alsa_default.cpp
| 
免费注册
发表于 2011-12-22 08:51
支持啊
发表于 2012-05-22 11:56