java的RIL框架处理modem网络状态改变事件的流程

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PhoneApp收到一个RIL_UNSOL_RESPONSE_NETWORK_STATE_CHANGED网络状态变化事件。
发送message到注册的handler上。GsmServiceStateTracker的构造方法将GsmServiceStateTracker对象本身注册到mNetworkStateRegistrants
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PhoneApp->GSMPhone(phone)->RIL(mCM)->RILReceiver(mReceiver)::run()
    readRilMessage(InputStream is, byte[] buffer)
        processResponse(Parcel p)
            processUnsolicited(Parcel p)
                PhoneApp->GSMPhone(phone)->RIL(mCM)->RegistrantList(mNetworkStateRegistrants)::notifyRegistrants(AsyncResult ar)

RIL.java            
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            case RIL_UNSOL_RESPONSE_NETWORK_STATE_CHANGED:
                if (RILJ_LOGD) unsljLog(response);
                Log.d(TAG, ">>>>>>>>>>>> processUnsolicited RIL_UNSOL_RESPONSE_NETWORK_STATE_CHANGED = " + responseToString(response));
                mNetworkStateRegistrants
                    .notifyRegistrants(new AsyncResult(null, null, null));
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GsmServiceStateTracker检测到事件类型为网络状态变，发送主动请求获取新的状态信息等
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PhoneApp->GSMPhone(phone)->GsmServiceStateTracker(mSST)::handleMessage(Message msg)
    pollState()
        cm.getOperator(msg),cm.getGPRSRegistrationState(msg),cm.getRegistrationState(msg),cm.getNetworkSelectionMode(msg)

GsmServiceStateTracker.java
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            case EVENT_NETWORK_STATE_CHANGED:
                Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker handleMessage EVENT_NETWORK_STATE_CHANGED");
                pollState();
                break;
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PhoneApp收到请求响应的事件。将事件绑定的消息发回给所属的handler
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PhoneApp->GSMPhone(phone)->RIL(mCM)->RILReceiver(mReceiver)::run()
    readRilMessage(InputStream is, byte[] buffer)
        processResponse(Parcel p)
            processSolicited(Parcel p)
                rr.mResult.sendToTarget()
                            
                            
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GsmServiceStateTracker检测事件类型为网络状态变化响应结果，如果网络类型改变则通过binder调用TelephonyRegistry服务的notifyDataConnection方法。
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PhoneApp->GSMPhone(phone)->GsmServiceStateTracker(mSST)::handleMessage(Message msg)
    handlePollStateResult(int what, AsyncResult ar)
        pollStateDone()
            if (hasNetworkTypeChanged)phone.notifyDataConnection(null)
                PhoneApp->GSMPhone(phone)->DefaultPhoneNotifier(mNotifier)::notifyDataConnection()
                    PhoneApp->GSMPhone(phone)->DefaultPhoneNotifier(mNotifier)->ITelephonyRegistry(mRegistry)::notifyDataConnection()
                   
GsmServiceStateTracker.java             
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        if (hasGprsAttached) {
            Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasGprsAttached");
            gprsAttachedRegistrants.notifyRegistrants();
        }

        if (hasGprsDetached) {
                    Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasGprsDetached");
            gprsDetachedRegistrants.notifyRegistrants();
        }

        if (hasNetworkTypeChanged) {
                    Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasNetworkTypeChanged");
            phone.notifyDataConnection(null);
        }

        if (hasRoamingOn) {
                    Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasRoamingOn");
            roamingOnRegistrants.notifyRegistrants();
        }

        if (hasRoamingOff) {
                    Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasRoamingOff");
            roamingOffRegistrants.notifyRegistrants();
        }

        if (hasLocationChanged) {
                    Log.d(TAG, ">>>>>>>>>>>> GsmServiceStateTracker pollStateDone hasLocationChanged");
            phone.notifyLocationChanged();
        }
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SystemServer中的TelephonyRegistry服务notifyDataConnection方法。注意这里的执行上下文在systemserver进程中。
notifyDataConnection根据条件调用已经注册的callback。
通过TelephonyManager的ITelephonyRegistry远程代理listen接口能够在TelephonyRegistry服务中注册callback。在SystemServer中通过com.android.server.status.StatusBarPolicy.installIcons(context, statusBar)向TelephonyRegistry服务注册了一个callback。
callback本身是IPhoneStateListener的一个远程代理对象。（实际上IPhoneStateListener的远程服务也在当前SystemServer进程）
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TelephonyRegistry::notifyDataConnection()
    if ((r.events & PhoneStateListener.LISTEN_DATA_CONNECTION_STATE) != 0)r.callback.onDataConnectionStateChanged(state, networkType);
  

   
   

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callback远程服务执行环境是在SystemServer进程中的。构造一个message发送给mhandler。
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StatusBarPolicy->匿名PhoneStateListener子类(mPhoneStateListener)->匿名binder服务类(callback)::onDataConnectionStateChanged
    Message.obtain(mHandler, LISTEN_DATA_CONNECTION_STATE, state, networkType, null).sendToTarget();

PhoneStateListener.java
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        public void onDataConnectionStateChanged(int state, int networkType) {
            Log.d(TAG, ">>>>>>>>>>>>PhoneStateListener.callback onDataConnectionStateChanged state = " + state + ", networkType = " + networkType);
            Message.obtain(mHandler, LISTEN_DATA_CONNECTION_STATE, state, networkType, null).
                    sendToTarget();
        }
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mHandler是StatusBarPolicy->PhoneStateListener成员属性。使用的是主线程的默认loop，也就是SystemServer的主线程。然后调用statusbarservice更新状态栏图标。
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StatusBarPolicy->PhoneStateListener(mPhoneStateListener)->Handler(handler)::handleMessage()
    PhoneStateListener.this.onDataConnectionStateChanged(msg.arg1, msg.arg2);
        updateDataNetType(networkType);
        updateDataIcon();


StatusBarPolicy.java
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        @Override
        public void onDataConnectionStateChanged(int state, int networkType) {
        Log.d(TAG, ">>>>>>>>>>>>StatusBarPolicy.PhoneStateListener onDataConnectionStateChanged state = " + state + ", networkType = " + networkType);
            mDataState = state;
            updateDataNetType(networkType);
            updateDataIcon();
        }
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