在android中，APP通過SmsManager.java一系列方法實現發送短信的功能，而發送的內容有很很多種，比如sendTextMessage、sendMultipartTextMessage、sendDataMessage等等，在這篇文章里我們就以其中一個為例闡述發送短信的完整流程，如果有不對的地方，請大家指正，一起學習。
1. 起點：SmsManager.java (frameworks/base/telephony/java/android/telephony/SmsManager.java)
sendTextMessage的核心代碼如下：
view plaincopy to clipboardprint?public void sendTextMessage(?
????????? ......?
?????? try {?
?????????? ISms iccISms = ISms.Stub.asInterface(ServiceManager.getService("isms"));?
?????????? if (iccISms != null) {?
?????????????? iccISms.sendText(destinationAddress, scAddress, text, sentIntent, deliveryIntent);?
?????????? }?
?????? } catch (RemoteException ex) {?
?????????? // ignore it??
?????? }?
?? }?
?public void sendTextMessage(
?????????? ......
??????? try {
??????????? ISms iccISms = ISms.Stub.asInterface(ServiceManager.getService("isms"));
??????????? if (iccISms != null) {
??????????????? iccISms.sendText(destinationAddress, scAddress, text, sentIntent, deliveryIntent);
??????????? }
??????? } catch (RemoteException ex) {
??????????? // ignore it
??????? }
??? }其中，view plaincopy to clipboardprint?ISms iccISms = ISms.Stub.asInterface(ServiceManager.getService("isms"));?
ISms iccISms = ISms.Stub.asInterface(ServiceManager.getService("isms"));是通過AIDL的方式，獲得服務，再調用這個服務對象的sendText()方法，那這個服務對象在哪里呢？
2. 我們知道，在eclipse中創建一個xx.aidl文件后，IDE會利用相關工具自動生成一個名為xx.java的接口，它有一個名為Stub的內部類，那我們自己創建一個類并繼承這個內部類，則可以實現了進程間的通信，這個是aidl的知識，這兒不詳述。我們往下看：
公司設立流程詳細，根據aidl的實現流程，那該服務對象應該是繼承了ISms.Stub，經過查找我們發現這個服務類：IccSmsInterfaceManagerProxy.java，所以從SmsManager.sendTextMessage()方法調用了IccSmsInterfaceManagerProxy對象的sendText()方法。
3. 第二階段：IccSmsInterfaceManagerProxy.java(frameworks/base/telephony/java/com/android/internal/telephony/IccSmsInterfaceManagerProxy)
我們看IccSmsInterfaceManagerProxy的sendText()方法核心代碼：
view plaincopy to clipboardprint?private IccSmsInterfaceManager mIccSmsInterfaceManager;?
......?
public void sendText(String destAddr, String scAddr,?
??????????? String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {?
??????? mIccSmsInterfaceManager.sendText(destAddr, scAddr, text, sentIntent, deliveryIntent);?
??? }?
private IccSmsInterfaceManager mIccSmsInterfaceManager;
......
public void sendText(String destAddr, String scAddr,
??????????? String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
??????? mIccSmsInterfaceManager.sendText(destAddr, scAddr, text, sentIntent, deliveryIntent);
??? }
繼續調用，此時調用的是IccSmsInterfaceManager對象的sendText()方法，那IccSmsInterfaceManager是什么玩意？？
4. 第三階段：IccSmsInterfaceManager.java(frameworks/base/telephony/java/com/android/internal/telephony/IccSmsInterfaceManager.java)
Android。從代碼看出IccSmsInterfaceManager是一個繼承了ISms.Stub的抽象類，相關核心代碼如下：
view plaincopy to clipboardprint?protected SMSDispatcher mDispatcher;?
public void sendText(String destAddr, String scAddr,?
??????????? String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {?
??????? mPhone.getContext().enforceCallingPermission(?
??????????????? "android.permission.SEND_SMS",?
??????????????? "Sending SMS message");?
??????? if (Log.isLoggable("SMS", Log.VERBOSE)) {?
??????????? log("sendText: destAddr=" + destAddr + " scAddr=" + scAddr +?
??????????????? " text='"+ text + "' sentIntent=" +?
??????????????? sentIntent + " deliveryIntent=" + deliveryIntent);?
??????? }?
??????? mDispatcher.sendText(destAddr, scAddr, text, sentIntent, deliveryIntent);?
??? }?
protected SMSDispatcher mDispatcher;
public void sendText(String destAddr, String scAddr,
??????????? String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
??????? mPhone.getContext().enforceCallingPermission(
??????????????? "android.permission.SEND_SMS",
??????????????? "Sending SMS message");
??????? if (Log.isLoggable("SMS", Log.VERBOSE)) {
??????????? log("sendText: destAddr=" + destAddr + " scAddr=" + scAddr +
??????????????? " text='"+ text + "' sentIntent=" +
??????????????? sentIntent + " deliveryIntent=" + deliveryIntent);
??????? }
??????? mDispatcher.sendText(destAddr, scAddr, text, sentIntent, deliveryIntent);
??? }
IccSmsInterfaceManager對象的sendText()方法調用了SMSDispatcher類的sendText()方法，繼續往下：
5. 第四階段：SMSDispatcher.java(frameworks/base/telephony/java/com/android/internal/telephony/SMSDispatcher.java)
該類是一個抽象類，它的sendText()并沒有實現，它的實現類是GsmSMSDispatcher.java或者CdmaSMSDispatcher.java,假設我們用的GSM網絡，則此時調用到GsmSMSDispatcher的sendText()方法。
6. 第五階段：GsmSMSDispatcher.java(frameworks/base/telephony/java/com/android/internal/telephony/gsm/GsmSMSDispatcher.java)
核心代碼如下：
活動流程？view plaincopy to clipboardprint?protected void sendText(String destAddr, String scAddr, String text,?
??????????? PendingIntent sentIntent, PendingIntent deliveryIntent) {?
??????? SmsMessage.SubmitPdu pdu = SmsMessage.getSubmitPdu(?
??????????????? scAddr, destAddr, text, (deliveryIntent != null));?
??????? sendRawPdu(pdu.encodedScAddress, pdu.encodedMessage, sentIntent, deliveryIntent);?
??? }?
......?
protected void sendText(String destAddr, String scAddr, String text,
??????????? PendingIntent sentIntent, PendingIntent deliveryIntent) {
??????? SmsMessage.SubmitPdu pdu = SmsMessage.getSubmitPdu(
??????????????? scAddr, destAddr, text, (deliveryIntent != null));
??????? sendRawPdu(pdu.encodedScAddress, pdu.encodedMessage, sentIntent, deliveryIntent);
??? }
......
到這兒，"sendText()"這個字眼就沒了，換成了另外一個方法名：sendRawPdu(),追蹤這個方法可以發現它是SMSDispatcher.java的一個方法，這個類看著很眼熟吧？不錯，在第四階段我們已經和它打過交道了！我們來看看它的sendRawPdu到底是干嘛的：view plaincopy to clipboardprint?protected void sendRawPdu(byte[] smsc, byte[] pdu, PendingIntent sentIntent,?
??????????? PendingIntent deliveryIntent) {?
?????????? ......?
?????????? sendSms(tracker);?
?????????? .....?
?}?
protected void sendRawPdu(byte[] smsc, byte[] pdu, PendingIntent sentIntent,
??????????? PendingIntent deliveryIntent) {
?????????? ......
?????????? sendSms(tracker);
?????????? .....
?}又來了一個新方法名：sendSms(),從sendRawPdu()傳來的信息經過封裝傳遞給sendSms()方法進行處理，而在SMSDispatcher.java中，這個方法只是聲明了一下，它的具體實現由子類：GsmSMSDispatcher.java完成。下面我們來看GsmSMSDispatcher.java
7. 第六階段：GsmSMSDispatcher.java(frameworks/base/telephony/java/com/android/internal/telephony/gsm/GsmSMSDispatcher.java)
GsmSMSDispatcher.java的sendSms()方法核心代碼如下：
view plaincopy to clipboardprint?protected CommandsInterface mCm;?
?
protected void sendSms(SmsTracker tracker) {?
??????? HashMap map = tracker.mData;?
?
??????? byte smsc[] = (byte[]) map.get("smsc");?
??????? byte pdu[] = (byte[]) map.get("pdu");?
?
??????? Message reply = obtainMessage(EVENT_SEND_SMS_COMPLETE, tracker);?
??????? mCm.sendSMS(IccUtils.bytesToHexString(smsc),?
??????????????? IccUtils.bytesToHexString(pdu), reply);?
??? }?
protected CommandsInterface mCm;
protected void sendSms(SmsTracker tracker) {
??????? HashMap map = tracker.mData;
登機流程，??????? byte smsc[] = (byte[]) map.get("smsc");
??????? byte pdu[] = (byte[]) map.get("pdu");
??????? Message reply = obtainMessage(EVENT_SEND_SMS_COMPLETE, tracker);
??????? mCm.sendSMS(IccUtils.bytesToHexString(smsc),
??????????????? IccUtils.bytesToHexString(pdu), reply);
??? }離成功已經不遠了....
我們知道，CommandsInterface是一個特殊的接口，它的RIL.java息息相關，而在上面的代碼中sendSms()調用來CommandsInterface對象的sendSMS()方法來做事情，而CommandsIterface是一個接口，所以事情只好由它的兒子(其實是孫子，RIL的爸爸BaseCommands是CommandsInterface的兒子)來完成，好，進入RIL.java.
8. 第七階段：RIL.java(/frameworks/base/telephony/java/com/android/internal/telephony/RIL.java)
只要研究過ril層的，對這玩意都一定很熟悉，所以直接看它的sendSMS()方法：
view plaincopy to clipboardprint?public void sendSMS (String smscPDU, String pdu, Message result) {?
??????? RILRequest rr?
??????????????? = RILRequest.obtain(RIL_REQUEST_SEND_SMS, result);?
?
??????? rr.mp.writeInt(2);?
??????? rr.mp.writeString(smscPDU);?
??????? rr.mp.writeString(pdu);?
?
??????? if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest));?
?
??????? send(rr);?
??? }?
?
//send(RILRequest rr)??
<pre name="code" class="java">private void?
??? send(RILRequest rr) {?
??????? Message msg;?
?
??????? msg = mSender.obtainMessage(EVENT_SEND, rr);?
?
??????? acquireWakeLock();?
?
??????? msg.sendToTarget();?
??? }?
public void sendSMS (String smscPDU, String pdu, Message result) {
??????? RILRequest rr
??????????????? = RILRequest.obtain(RIL_REQUEST_SEND_SMS, result);
安卓短信。??????? rr.mp.writeInt(2);
??????? rr.mp.writeString(smscPDU);
??????? rr.mp.writeString(pdu);
??????? if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest));
??????? send(rr);
??? }
//send(RILRequest rr)
<pre name="code" class="java">private void
??? send(RILRequest rr) {
??????? Message msg;
??????? msg = mSender.obtainMessage(EVENT_SEND, rr);
安卓手機怎么發送短信？??????? acquireWakeLock();
??????? msg.sendToTarget();
??? }
OK!在sendSMS()方法中，我們把上面所傳下來的東東寫入到Parcel中，協同一個特殊的RILRequest被發送出去，發送到哪里了？接著看：view plaincopy to clipboardprint?public void?
??????? handleMessage(Message msg) {?
??????????? RILRequest rr = (RILRequest)(msg.obj);?
??????????? RILRequest req = null;?
?
??????????? switch (msg.what) {?
??????????????? case EVENT_SEND:?
??????????????????? boolean alreadySubtracted = false;?
??????????????????? try {?
????????????????????? LocalSocket s;?
????????????????????? ......?
????????????????????? s.getOutputStream().write(dataLength);?
????????????????????? s.getOutputStream().write(data);?
??????????????????? } catch (IOException ex) {?
????????????????????? ......??????
??????????????????? }?
??????????????????? break;?
??????????? }?
??????? }?
public void
??????? handleMessage(Message msg) {
??????????? RILRequest rr = (RILRequest)(msg.obj);
??????????? RILRequest req = null;
??????????? switch (msg.what) {
??????????????? case EVENT_SEND:
??????????????????? boolean alreadySubtracted = false;
??????????????????? try {
????????????????????? LocalSocket s;
????????????????????? ......
????????????????????? s.getOutputStream().write(dataLength);
????????????????????? s.getOutputStream().write(data);
??????????????????? } catch (IOException ex) {
????????????????????? ......????
??????????????????? }
??????????????????? break;
??????????? }
??????? }重點：LocalSocket、s.getOutputStream().write(data)
我們把短信相關的數據及特殊RILRequst對象寫入到Socket的的輸出流中，進而將數據傳遞到RIL層，即底層，然后RIL層通過接收Socket中傳過來的數據解析得到請求內容并進行處理，到此，發短信的Java部分講完了。
RIL層以后再分析，如果文中有不對的地方，請大家告訴我，謝謝！
