11年下半年一直在做RIL的移植，主要解決第三方庫的一些bug，使之能更好的工作在公司的PAD上。但是后來發現遠遠不夠，有好多問題出現在Framework層。比方說我們想讓PAD支持熱插拔，盡管底層做好了，但上層還會出現很多問題，如PIN/PUK解鎖功能，用戶把解鎖PIN/PUK的界面打開但同時他把卡拔掉了，此時是無法解鎖的，系統該如何響應此時的情況，我們該怎么做，這都是需要了解Telephony Framework之后才知道如何實現的。

于是研究了一番Telephony的Java框架，剛開始接觸時感覺挺復雜很混亂，現在理清了關系，所以希望能幫到那些還在糾結中的同志。

我想大致以網絡連接為例分析Android Telephony Framework層，關于ril及其移植的文章有很多所以就不贅述了。

以下部分內容引自前段時期我關于Telephony的總結做的PPT，參考了不少前輩的文章，用英文寫的，懶得再譯回來了，湊合著看吧（當時為了翻譯成英文還煞費苦心- -！），需要PPT原件可以在此?http://wenku.baidu.com/view/bfe5361afad6195f312ba61c.html?下載，重要的和難理解的地方會做些解釋，文章較長，一篇日志不讓保存所以共分為四部分。

先來個整體結構圖，有個大致印象，看完本文回頭再看應該會有更深的理解。

?

1.Telephony Framework

Telephony framework contains a set of telephony API for applications. There are two?categaries?of JAVA?pacakges?in telephony framework:

1.The internal telephony packages -??

??com.android.internal.telephony.*,

???source code:?frameworks/base/telephony/java/com/android/internal/telephony

2.The open telephony packages -

??android.telephony.*.

???source code:?frameworks/base/telephony/java/android/telephony

The internal packages are used for Android default telephony application -?Phone.apk, and the open packages are for any 3rd?party telephony applications.

?

Internal Telephony Packages:

frameworks/base/telephony/java/com/android/internal/telephony

The public interface?Phone?is used to control the phone. The abstract class?PhoneBase?implements this interface. And the class?GSMPhone?extends this abstract class.

Phone.java

44 public interface Phone{ 326 String getPhoneName(); 332 int getPhoneType(); 1118 void setPreferredNetworkType(int networkType， Message response）； 1125 void getPreferredNetworkType（Message response）； ...

The default telephony application could use?makeDefaultPhones()?and?getDefaultPhone()?in the class?PhoneFactory?to obtain the unique instance of Phone. The code below shows how this be done.

packages/apps/Phone/src/com/android/phone/PhoneApp.java

410???? public void onCreate() { ? ? ? ? ?? ... 425???????? if (phone == null) { 426???????????? // Initialize the telephonyframework 427???????????? PhoneFactory.makeDefaultPhones(this); 428 429???????????? // Get the default phone 430???????????? phone = PhoneFactory.getDefaultPhone();

PhoneFactory.java

56 public static void makeDefaultPhone(Context context) { ... 130 sCommandsInterface = new RIL(context, networkMode, cdmaSubscription); 132 int phoneType = getPhoneType(networkMode); if (phoneType == Phone.PHONE_TYPE_GSM) { 135 sProxyPhone = new PhoneProxy(new GSMPhone(context, sCommandsInterface, sPhoneNotifier)); 137 } else if (phoneType == Phone.PHONE_TYPE_CDMA) {

Let’s suppose the current network mode is in GSM/GPRS, so the default telephony application could obtain a?PhoneProxy?to a?GSMPhone, and use its API to achieve telephony functionalities.ProxyPhone?is also extended from?Phone. It is used to abstract the specific instance of a specific network mode.

PhoneProxy.java

?57?????public PhoneProxy(Phone phone) {

?58?????????mActivePhone = phone;

????????????...

?66?????????mCommandsInterface = ((PhoneBase)mActivePhone).mCM;

?67?????????mCommandsInterface.registerForRadioTechnologyChanged(

?68?????????????????this, EVENT_RADIO_TECHNOLOGY_CHANGED, null);

?69?????}?

????????...

549?????public void getPreferredNetworkType(Message response) {

550?????????mActivePhone.getPreferredNetworkType(response);

551?????}????????

The class?PhoneBase?has a member?mCM?of the type?CommandsInterface. And this is assigned in the constructor of?GSMPhone.

GSMPhone.java

130?????GSMPhone (Context context,?CommandsInterface ci, PhoneNotifier notifier,

???????????????????????????????boolean unitTestMode) {

131?????????super(notifier, context,?ci, unitTestMode);

????????????...

PhoneBase.java

114?????public CommandsInterface mCM;

????????...

203?????protected PhoneBase(PhoneNotifier notifier, Context context, CommandsInterface ci,

204?????????????boolean unitTestMode) {

207?????????mLooper = Looper.myLooper();

208?????????mCM = ci;

????????...

757?????public void getPreferredNetworkType(Message response) {

758?????????mCM.getPreferredNetworkType(response);

759?????}

All the telephony functionalities which need sending AT command to RIL daemon should be achieved by the?the?interface?CommandsInterface. And the class?RIL?implements this interface.??Moreover,?RILalso extends the abstract class?BaseCommands?to provide unsolicited result code to default telephony application.

CommandsInterface.java

27?????public interface CommandsInterface {

1332?????void getPreferredNetworkType(Message response);

BaseCommands.java

36 public abstract class BaseCommands implements CommandsInterface {??????

RIL.java

199 public final class RIL extends BaseCommands implements CommandsInterface {

1861?????public void getPreferredNetworkType(Message response)?{

1862?????????RILRequest rr = RILRequest.obtain(

1863?????????????????RILConstants.RIL_REQUEST_GET_PREFERRED_NETWORK_TYPE, response);

1867?????????send(rr); //call sender and send to target

?
我想說說為何網絡需要用狀態機來管理，DcDefaultState是下面所有狀態的父狀態，子狀態無法處理的EVENT都由他來處理，這是狀態 機的機制，是大前提。

圖中初始狀態為紅色部分，在狀態未切換的時候，事件均由它來處理，無法處理的交給父狀態處理，當來一個EVENT_CONNECT的事件的時候，狀態切換到DcActivingState，此時若有事件發給狀態機，均在此狀態下處理，無法處理的交給父狀態處理，當網絡連接成功（SetupResult==SUCCESS），切換到綠色表示的狀態，綠色部分DcActiveState是表示網絡連接成功了，比如在此狀態下來個EVENT_CONNECT事件（此事件在網絡斷開的狀態下會發起網絡連接）它不會自己處理（因為此時網絡已經連接成功了，無需再連，此狀態下只會處理EVENT_DISCONNECT事件），而把該事件交由父狀態DcDefaultState來處理。

通過此機制，可以讓網絡狀態得到穩定有序的管理。

下圖展示了如何發起一個網絡連接 (最后為連接成功狀態）

?
下圖以HUAWEI-RIL 2.3為例，展示了第三方庫是如何對網絡請求響應的（ril的機制要有基本了解）
?

感覺Telephony有點復雜，事件多，Telephony不僅包括對Call，MMS，SIM?card，網絡連接等的管理，還包括運營商，電話薄，解鎖等功能揉在一塊，感覺非常龐大?，其實事件雖多，但框架都基本類似，也就是觸類旁通，掌握一個，自然能夠順藤摸瓜，解決其他的問題。 上面的圖根據ANDROID ICS的源碼畫的，華為模塊的RIL_VERSION 2.3。

下面的內容就是通知機制了，以網絡狀態變化為例，status?bar上信號一會2格一會滿格，其原理是怎么實現的呢

Telephony framework needs to track the network return value and events???happened in RIL daemon. At the same time, default telephony application should also be able to be notified by telephony framework.

In the constructor of?GSMPhone, a?GsmServiceStateTracker?would be created to track the network status. And in the?contructor?of?GsmServiceStateTracker, it would register to?RIL?for network status message.?

gsm/GSMPhone.java

101?????GsmServiceStateTracker mSST;

130?????public GSMPhone (Context context, CommandsInterface ci, PhoneNotifier notifier,

??????????????????boolean unitTestMode) {

????????????...

139?????????mSST = new GsmServiceStateTracker (this);

gsm/GsmServiceStateTracker.java

186?????public GsmServiceStateTracker(GSMPhone phone) {

189????????this.phone = phone;

190????????cm = phone.mCM;

204????????cm.registerForVoiceNetworkStateChanged(this, EVENT_NETWORK_STATE_CHANGED, null);

It registers into a registrant list of?BaseCommands.

BaseCommands.java

58??????protected RegistrantList mVoiceNetworkStateRegistrants = new RegistrantList();

????????...

324?????public void registerForVoiceNetworkStateChanged(Handler h, int what, Object obj) {

325?????????Registrant r =?new Registrant (h, what, obj);

327?????????mVoiceNetworkStateRegistrants.add(r);

328?????}

When network state changes, the endless loop waiting for the message in telephony framework will be notified by RIL daemon. And the message is?deliverred?to registrant.

RIL.java

2395?????private void

2396?????processUnsolicited (Parcel p) {

?????????????????...

2467?????????????case RIL_UNSOL_RESPONSE_VOICE_NETWORK_STATE_CHANGED:

2468?????????????????if (RILJ_LOGD) unsljLog(response);

2469

2470?????????????????mVoiceNetworkStateRegistrants

2471?????????????????????.notifyRegistrants(new?AsyncResult(null, null, null));

GsmServiceStateTracker?is a subclass of Handler.

When RILJ call?notifyRegistrants(), the?registed?handler?obj?will call?sendMessage(msg), thenhandleMessage() will be call.

gsm/GsmServiceStateTracker.java

260?????public void handleMessage (Message msg) {

261?????????AsyncResult ar;

262?????????int[] ints;

263?????????String[] strings;

264?????????Message message;

265

266?????????switch (msg.what) {

????????????????...

304?????????????case?EVENT_NETWORK_STATE_CHANGED:

305?????????????????pollState();

306?????????????????break;

Open telephony packages:

frameworks/base/telephony/java/android/telephony

??????

TelephonyManager?provides a way for 3rd application??interacting with internal telephony packages.

Class Overview (from android?sdk?document)

Provides access to information about the telephony services on the device. Applications can use the methods in this class to determine telephony services and states, as well as to access some types of subscriber information. Applications can also register a listener to receive notification of telephony state changes.

You do not instantiate this class directly; instead, you retrieve a reference to an instance throughContext.getSystemService(Context.TELEPHONY_SERVICE).

Note that access to some telephony information is?permission-protected. Your application cannot access the protected information unless it has the appropriate permissions declared in its manifest file. Where permissions apply, they are noted in the?the?methods through which you access the protected information.

?這個圖我想詳細的說一下，這個圖演示了第三方應用，Phone Service及Telephony的關系。

第一條主線，以TelephonyManager為軸的上半部分，PhoneApp是一個非常特殊的app，由它通過調用PhoneFactory'創建一個Telephony（Internal），同時給第三方application暴露接口，供其通過TelephonyManager調用，TelephonyManager通過ITelephony（android的AIDL機制）獲得PhoneInterfaceManager的遠程對象，然后第三方application通過這個遠程對象來調用service里的方法，這里的調用是兩個獨立進程之間進行的（如果不清楚aidl，可以假想為3rd?application直接調用了PhoneInterfaceManager里的方法，但實際上是需要通過TelephonyManager才能調用的）

第二條主線，以TelephonyManager為軸的右半部分，TelephonyRegistry，顧名思義，是什么東西的注冊，這種注冊的一般都是為了實現回調功能，這個類的主要作用就是把第三方App里new的PhoneStateListener和需要監聽的動作通過調用TelephonyManager注冊到TelephonyRegistry，當底層狀態變化通知GSMPhone時，GSMPhone里的DefaultPhoneNotifier會通知TelephonyRegistry，然后注冊到TelephonyRegistry的PhoneStateListener監聽的事件會被觸發（此時TelephonyRegistry還會發個boardCast），然后回調上層APP復寫的方法。

（要理清關系的最好辦法就是結合圖閱讀源碼，那樣會有更深的理解）

如果上面的機制看不懂也沒關系，作為SDK開發只要知道以下部分就行,

If we want to track telephony state in 3rd?application:

1??We should?retrive?an instance of?TelephonyManager?and get Phone service. ? ? ?//needed 2 ?Implement a?PhoneStateListener?what you want to listen. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? //not needed 3 ?You can also register a?BroadCastReceiver?to receive broadcast if you want. ? ? ? //not needed 4 ?Don’t forget add permission in manifest file. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?//needed

Take Settings as example to show how to achieve these.

packages/apps/Settings/src/com/android/settings/deviceinfo/ Status.java

111?????private TelephonyManager mTelephonyManager;

???????

169?????private PhoneStateListener mPhoneStateListener = new PhoneStateListener() {

170?????????@Override

171?????????public void?onDataConnectionStateChanged(int state) {

???????????????UpdateDataState();??//you can override with your own code here

???????

178?????protected void onCreate(Bundle icicle) {????????????

184?????????mTelephonyManager = (TelephonyManager)getSystemService(TELEPHONY_SERVICE);

268?????protected void onResume() {

278?????????????mTelephonyManager.listen(mPhoneStateListener,

279???????????????????????PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);

337?????private void updateDataState() {

338?????????int state = mTelephonyManager.getDataState();

341?????????switch (state) {

總結

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