Android短信发送流程之普通短信发送（原）

 我们先来看最简单的流程入手分析，即收件人只有一个，而且不是长短信的情况。

一、地址有效性检测

        当点击发送按钮时，触发onClick事件：

 @ComposeMessageActivity.java
 public void onClick(View v) {
     if ((v == mSendButtonSms || v == mSendButtonMms) && isPreparedForSending()) {
         //确认发送
         confirmSendMessageIfNeeded();
     } else if ((v == mRecipientsPicker)) {
         launchMultiplePhonePicker();
     }
 }

        然后进行 收件人地址信息的确认：

 private void confirmSendMessageIfNeeded() {
     if (!isRecipientsEditorVisible()) {
         //当前的收件人编辑框不可见，说明所发送的对象已经存在短信的会话，也说明当前的收件人地址是ok的
         sendMessage(true);
         return;
     }
     //判断是否为MMS
     boolean isMms = mWorkingMessage.requiresMms();
     if (mRecipientsEditor.hasInvalidRecipient(isMms)) {
         //当前的收件人列表中包含无效地址
         if (mRecipientsEditor.hasValidRecipient(isMms)) {
             //当前的收件人列表中有无效地址和有效地址，提示用户是否忽略，只发送有效的地址
             String title = getResourcesString(R.string.has_invalid_recipient,
                     mRecipientsEditor.formatInvalidNumbers(isMms));
             new AlertDialog.Builder(this)
                 .setTitle(title)
                 .setMessage(R.string.invalid_recipient_message)
                 .setPositiveButton(R.string.try_to_send,
                         new SendIgnoreInvalidRecipientListener())
                 .setNegativeButton(R.string.no, new CancelSendingListener())
                 .show();
         } else {
             //当前的收件人列表中的地址全部无效，取消发送，提示用户
             new AlertDialog.Builder(this)
                 .setTitle(R.string.cannot_send_message)
                 .setMessage(R.string.cannot_send_message_reason)
                 .setPositiveButton(R.string.yes, new CancelSendingListener())
                 .show();
         }
     } else {
         //收件人地址都是有效的，发送
         ContactList contacts = mRecipientsEditor.constructContactsFromInput(false);
         mDebugRecipients = contacts.serialize();
         sendMessage(true);
     }
 }

        经过地址有效性检测后，通过sendMessage()继续流程，这里传递的bCheckEcmMode参数代表是否检查当前Phone的状态， 处于紧急状态时无法发送短信:

 private void sendMessage(boolean bCheckEcmMode) {
     if (bCheckEcmMode) {
         //判断当前是否为紧急呼叫模式
         String inEcm = SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE);
         if (Boolean.parseBoolean(inEcm)) {
             try {
                 //紧急状态下，无法发送短彩信
                 startActivityForResult( new Intent(TelephonyIntents.ACTION_SHOW_NOTICE_ECM_BLOCK_OTHERS, null), REQUEST_CODE_ECM_EXIT_DIALOG);
                 return;
             } catch (ActivityNotFoundException e) {
                 Log.e(TAG, "Cannot find EmergencyCallbackModeExitDialog", e);
             }
         }
     }
     //判断当前是否有短信正在发送
     if (!mSendingMessage) {
         //重置收件人控件的监听器
         removeRecipientsListeners();
         //进入WorkingMessage处理流程
         mWorkingMessage.send(mDebugRecipients);


         mSentMessage = true;
         mSendingMessage = true;
         addRecipientsListeners();


         mScrollOnSend = true;   // in the next onQueryComplete, scroll the list to the end.
     }
     // But bail out if we are supposed to exit after the message is sent.
     if (mSendDiscreetMode) {
         finish();
     }
 }

二、创建短彩信的发送线程

        在sendMessage()中经过对当前紧急服务的处理，然后判断如果当前没有短信正在发送，则通过WorkingMessage发送短信。这里的WorkingMessage是处理当前所编辑的信息的工具类，没有父类，在ComposeMessageActivity界面被创建时或者短信被发送出去时创建， 主要负责区分短彩信的流程以及发送短信时UI的更新。

 @WorkingMessage.java
 public void send(final String recipientsInUI) {
     long origThreadId = mConversation.getThreadId();
     removeSubjectIfEmpty(true /* notify */);
     prepareForSave(true /* notify */);


     //拿到当前的会话
     final Conversation conv = mConversation;
     String msgTxt = mText.toString();


     if (requiresMms() || addressContainsEmailToMms(conv, msgTxt)) {
         //彩信发送
         if (MmsConfig.getUaProfUrl() == null) {
             String err = "WorkingMessage.send MMS sending failure. mms_config.xml is " +
                 "missing uaProfUrl setting.  uaProfUrl is required for MMS service, " +
                 "but can be absent for SMS.";
             RuntimeException ex = new NullPointerException(err);
             Log.e(TAG, err, ex);
             // now, let's just crash.
             throw ex;
         }
         final Uri mmsUri = mMessageUri;
         final PduPersister persister = PduPersister.getPduPersister(mActivity);


         final SlideshowModel slideshow = mSlideshow;
         final CharSequence subject = mSubject;
         final boolean textOnly = mAttachmentType == TEXT;




         //彩信发送线程
         new Thread(new Runnable() {
             @Override
             public void run() {
                 final SendReq sendReq = makeSendReq(conv, subject);
                 slideshow.prepareForSend();
                 sendMmsWorker(conv, mmsUri, persister, slideshow, sendReq, textOnly);
                 updateSendStats(conv);
             }
         }, "WorkingMessage.send MMS").start();
     } else {
         //短信发送流程
         final String msgText = mText.toString();
         new Thread(new Runnable() {
             @Override
             public void run() {
                 preSendSmsWorker(conv, msgText, recipientsInUI);


                 updateSendStats(conv);
             }
         }, "WorkingMessage.send SMS").start();
     }


     // update the Recipient cache with the new to address, if it's different
     RecipientIdCache.updateNumbers(conv.getThreadId(), conv.getRecipients());
     // Mark the message as discarded because it is "off the market" after being sent.
     mDiscarded = true;
 }

        在上面的send流程中，WorkingMessage对短彩信进行分类， 分别创建子线程进行发送，本节我们只关注短信流程，他是在preSendSmsWorker()中被发送的：

 private void preSendSmsWorker(Conversation conv, String msgText, String recipientsInUI) {
     UserHappinessSignals.userAcceptedImeText(mActivity);
     //UI刷新
     mStatusListener.onPreMessageSent();
     //获取初始的线程ID
     long origThreadId = conv.getThreadId();
     //获取分配的线程ID
     long threadId = conv.ensureThreadId();
     String semiSepRecipients = conv.getRecipients().serialize();


     // recipientsInUI can be empty when the user types in a number and hits send
     if (LogTag.SEVERE_WARNING && ((origThreadId != 0 && origThreadId != threadId) || (!semiSepRecipients.equals(recipientsInUI) && !TextUtils.isEmpty(recipientsInUI)))) {
     }else {
         //发送短信
         sendSmsWorker(msgText, semiSepRecipients, threadId);
         //删除草稿
         deleteDraftSmsMessage(threadId);
     }
 }

        在上面的preSendSmsWorker中进行了四个处理：

            1、更新UI(更新编辑框等控件)；

            2、获取当前发送的ThreadID；

            3、发送短信；

            4、删除草稿；

        接下来我们继续来看发送的过程：

 private void sendSmsWorker(String msgText, String semiSepRecipients, long threadId) {
     //获取当前发送的收件人地址
     String[] dests = TextUtils.split(semiSepRecipients, ";");
     //获取MessageSender对象，传递进去4个参数分别为：收件人、信息文本、当前的threadId、SimID。
     MessageSender sender = new SmsMessageSender(mActivity, dests, msgText, threadId);
     try {
         //通过MessageSender发送出去
         sender.sendMessage(threadId);
         // Make sure this thread isn't over the limits in message count
         Recycler.getSmsRecycler().deleteOldMessagesByThreadId(mActivity, threadId);
     } catch (Exception e) {
         Log.e(TAG, "Failed to send SMS message, threadId=" + threadId, e);
     }
     //更新UI
     mStatusListener.onMessageSent();
     MmsWidgetProvider.notifyDatasetChanged(mActivity);
 }

        经过上面WorkingMessage的sendSmsWorker过程，创建了MessageSender对象，并通过该对象的sendMessage()方法将信息发送出去，并在发送之后再次更新UI界面(正在发送中)。

三、通过SmsMessageSender拆分多个收件人

        上面创建的MessageSender对象，继承自MessageSender接口，主要方法只有三个：

 public boolean sendMessage(long token) throws MmsException {};
 private boolean queueMessage(long token) throws MmsException {};
 private String getOutgoingServiceCenter(long threadId) {};

        他的主要作用就是 对当前收件人信息拆分后，把群发的短信构建成一个短信队列并保存在数据库中，然后通知SmsReceiverService将队列读取出来并发送出去。
        下面来看其具体实现过程。

 @SmsMessageSender.java
 public boolean sendMessage(long token) throws MmsException {
     return queueMessage(token);
 }
 private boolean queueMessage(long token) throws MmsException {
     if ((mMessageText == null) || (mNumberOfDests == 0)) {
         //空信息不能发送
         throw new MmsException("Null message body or dest.");
     }


     SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
     boolean requestDeliveryReport = prefs.getBoolean(
             MessagingPreferenceActivity.SMS_DELIVERY_REPORT_MODE,
             DEFAULT_DELIVERY_REPORT_MODE);


     //根据当前短信的收件人数目，遍历当前的发送队列
     for (int i = 0; i < mNumberOfDests; i++) {
         try {
             //将当前要发送的短消息放入发送队列中
             Sms.addMessageToUri(mContext.getContentResolver(),
                     Uri.parse("content://sms/queued"), mDests[i],
                     mMessageText, null, mTimestamp,
                     true /* read */,
                     requestDeliveryReport,
                     mThreadId);
         } catch (SQLiteException e) {
             if (LogTag.DEBUG_SEND) {
                 Log.e(TAG, "queueMessage SQLiteException", e);
             }
             SqliteWrapper.checkSQLiteException(mContext, e);
         }
     }
     //通知SmsReceiverService发送短信
     mContext.sendBroadcast(new Intent(SmsReceiverService.ACTION_SEND_MESSAGE,
                 null,
                 mContext,
                 SmsReceiver.class));
     return false;
 }

        在上面这个过程中，将收件人地址拆分后，生成一个短信队列放入"content://sms/queued"中，然后给SmsReceiver发送了通知，这里的SmsReceiver作用仅仅是将该通知转发给SmsReceiverService而已：

 @SmsReceiver.java
 public void onReceive(Context context, Intent intent) {
     onReceiveWithPrivilege(context, intent, false);
 }
 protected void onReceiveWithPrivilege(Context context, Intent intent, boolean privileged) {
     if (!privileged && intent.getAction().equals(Intents.SMS_DELIVER_ACTION)) {
         return;
     }


     //将请求转交给SmsReceiverService来处理
     intent.setClass(context, SmsReceiverService.class);
     intent.putExtra("result", getResultCode());
     beginStartingService(context, intent);
 }

        也就是说，SmsMessageSender将要发送的短信放入队列中之后，经过SmsReceiver将该消息发送给了SmsReceiverService， 这里的SmsReceiverService是负责短信的收发的Service。
        下面来看SmsReceiverService对于发送短消息的处理过程。
        这个Service被创建时，会创建一个子线程(HandlerThread)以及该线程的Handler对象(ServiceHandler)：

 @SmsReceiverService.java
 public void onCreate() {
     //创建子线程处理各种消息
     HandlerThread thread = new HandlerThread(TAG, Process.THREAD_PRIORITY_BACKGROUND);
     thread.start();


     mServiceLooper = thread.getLooper();
     mServiceHandler = new ServiceHandler(mServiceLooper);
 }

        当该Service被启动时，就会对当前的请求进行处理：

 public int onStartCommand(Intent intent, int flags, int startId) {
     mResultCode = intent != null ? intent.getIntExtra("result", 0) : 0;
     //通知Handler处理当前的请求
     Message msg = mServiceHandler.obtainMessage();
     msg.arg1 = startId;
     msg.obj = intent;
     mServiceHandler.sendMessage(msg);
     return Service.START_NOT_STICKY;
 }

        然后看当前Handler的处理：

 private final class ServiceHandler extends Handler {
     public ServiceHandler(Looper looper) {
         super(looper);
     }
     @Override
     public void handleMessage(Message msg) {
         int serviceId = msg.arg1;
         Intent intent = (Intent)msg.obj;
         if (intent != null && MmsConfig.isSmsEnabled(getApplicationContext())) {
             String action = intent.getAction();
             int error = intent.getIntExtra("errorCode", 0);


             if (MESSAGE_SENT_ACTION.equals(intent.getAction())) {
                 handleSmsSent(intent, error);
             } else if (SMS_DELIVER_ACTION.equals(action)) {
                 handleSmsReceived(intent, error);
             } else if (ACTION_BOOT_COMPLETED.equals(action)) {
                 handleBootCompleted();
             } else if (TelephonyIntents.ACTION_SERVICE_STATE_CHANGED.equals(action)) {
                 handleServiceStateChanged(intent);
             } else if (ACTION_SEND_MESSAGE.endsWith(action)) {
                 //发送短信
                 handleSendMessage();
             } else if (ACTION_SEND_INACTIVE_MESSAGE.equals(action)) {
                 handleSendInactiveMessage();
             }
         }
         SmsReceiver.finishStartingService(SmsReceiverService.this, serviceId);
     }
 }

        从上面的case分支中我们看到，对于当前的发送短信的请求( ACTION_SEND_MESSAGE)将会通过handleSendMessage()来处理：

 private void handleSendMessage() {
     if (!mSending) {
         //当前没有其他任务时就触发发送的操作
         sendFirstQueuedMessage();
     }
 }
 public synchronized void sendFirstQueuedMessage() {
     boolean success = true;
     final Uri uri = Uri.parse("content://sms/queued");
     ContentResolver resolver = getContentResolver();
     //从队列中拿到要发送的短信
     Cursor c = SqliteWrapper.query(this, resolver, uri, SEND_PROJECTION, null, null, "date ASC");
     if (c != null) {
         try {
             //发送队列中第一条短信
             if (c.moveToFirst()) {
                 String msgText = c.getString(SEND_COLUMN_BODY);
                 String address = c.getString(SEND_COLUMN_ADDRESS);
                 int threadId = c.getInt(SEND_COLUMN_THREAD_ID);
                 int status = c.getInt(SEND_COLUMN_STATUS);
                 int msgId = c.getInt(SEND_COLUMN_ID);
                 Uri msgUri = ContentUris.withAppendedId(Sms.CONTENT_URI, msgId);
                 //构建SmsSingleRecipientSender对象
                 SmsMessageSender sender = new SmsSingleRecipientSender(this,
                         address, msgText, threadId, status == Sms.STATUS_PENDING,
                         msgUri);


                 try {
                     //发送
                     sender.sendMessage(SendingProgressTokenManager.NO_TOKEN);;
                     mSending = true;
                 } catch (MmsException e) {
                     mSending = false;
                     messageFailedToSend(msgUri, SmsManager.RESULT_ERROR_GENERIC_FAILURE);
                     success = false;
                     sendBroadcast(new Intent(SmsReceiverService.ACTION_SEND_MESSAGE,
                             null,
                             this,
                             SmsReceiver.class));
                 }
             }
         } finally {
             c.close();
         }
     }
     if (success) {
         unRegisterForServiceStateChanges();
     }
 }

        我们看到，经过SmsReceiverService中Handler的处理，将数据库中的当前要发送的短信队列取出来，然后取出队列中第一个短消息任务，通过SmsSingleRecipientSender的sendMessage()方法发送出去。至此SmsReceiverService的流程就走完了，他的作用主要就是拿到队列中的第一条短消息，构建SmsSingleRecipientSender对象并发送出去。

四、通过SmsSingleRecipientSender拆分长短信

        SmsSingleRecipientSender类继承自SmsMessageSender，他所提供的方法只有一个：

 public boolean sendMessage(long token) throws MmsException {};

        其处理内容就是对长短消息进行分割。然后注册两个广播(一个用于广播当前正在发送，另一个广播短信的送达状态报告)，之后通过SmsManager发送出去。

 @SmsSingleRecipientSender.java
 public boolean sendMessage(long token) throws MmsException {
     if (mMessageText == null) {
         throw new MmsException("Null message body or have multiple destinations.");
     }
     SmsManager smsManager = SmsManager.getDefault();
     ArrayList messages = null;
     //拆分长短信
     if ((MmsConfig.getEmailGateway() != null) && (Mms.isEmailAddress(mDest) || MessageUtils.isAlias(mDest))) {
         //彩信
         String msgText;
         msgText = mDest + " " + mMessageText;
         mDest = MmsConfig.getEmailGateway();
         messages = smsManager.divideMessage(msgText);
     } else {
         //短信
         messages = smsManager.divideMessage(mMessageText);
         mDest = PhoneNumberUtils.stripSeparators(mDest);
         mDest = Conversation.verifySingleRecipient(mContext, mThreadId, mDest);
     }
     int messageCount = messages.size();


     if (messageCount == 0) {
         throw new MmsException("SmsMessageSender.sendMessage: divideMessage returned " + "empty messages. Original message is \"" + mMessageText + "\"");
     }


     boolean moved = Sms.moveMessageToFolder(mContext, mUri, Sms.MESSAGE_TYPE_OUTBOX, 0);
     if (!moved) {
         throw new MmsException("SmsMessageSender.sendMessage: couldn't move message " + "to outbox: " + mUri);
     }
     ArrayList deliveryIntents =  new ArrayList(messageCount);
     ArrayList sentIntents = new ArrayList(messageCount);
     for (int i = 0; i < messageCount; i++) {
         if (mRequestDeliveryReport && (i == (messageCount - 1))) {
             //所有短信被发送完毕后，在最后一条短信后面添加送达报告的Intent
             deliveryIntents.add(PendingIntent.getBroadcast(
                         mContext, 0,
                         new Intent(
                             MessageStatusReceiver.MESSAGE_STATUS_RECEIVED_ACTION,
                             mUri,
                             mContext,
                             MessageStatusReceiver.class),
                         0));
         } else {
             deliveryIntents.add(null);
         }
         //对于拆分后的短消息，需要在每条信息发送完毕后发送该Intent，从而接着发送剩下的拆分短信
         Intent intent  = new Intent(SmsReceiverService.MESSAGE_SENT_ACTION,
                 mUri,
                 mContext,
                 SmsReceiver.class);


         int requestCode = 0;
         if (i == messageCount -1) {
             //收到该附加数据说明当前的拆分短信已经发送完毕
             requestCode = 1;
             intent.putExtra(SmsReceiverService.EXTRA_MESSAGE_SENT_SEND_NEXT, true);
         }
         sentIntents.add(PendingIntent.getBroadcast(mContext, requestCode, intent, 0));
     }
     try {
         //发送
         smsManager.sendMultipartTextMessage(mDest, mServiceCenter, messages, sentIntents, deliveryIntents);
     } catch (Exception ex) {
         throw new MmsException("SmsMessageSender.sendMessage: caught " + ex + " from SmsManager.sendTextMessage()");
     }
     return false;
 }

        经过上面的准备过程，在通过SmsManager发送信息之前，还添加了两个Intent：SmsReceiverService.MESSAGE_SENT_ACTION和MessageStatusReceiver.MESSAGE_STATUS_RECEIVED_ACTION。这两个Intent的作用分别是：
         MESSAGE_STATUS_RECEIVED_ACTION:当所有长短信(或短消息)发送完毕后，发送该Intent。
         MESSAGE_SENT_ACTION:分割后的短消息，每发送一条，都会发送该Intent， 当最后一条发送完毕后，将会在该Intent中附加EXTRA_MESSAGE_SENT_SEND_NEXT=true的数据。
        具体细节在发送完毕后再分析。
        接下来看SmsManager，这里的SmsManager是 单例模型，通过其自己的getDefault()或者getSmsManagerForSubscriber()方法就可以得到该对象。

 @SmsManager.java
 public void sendMultipartTextMessage( String destinationAddress, String scAddress, ArrayList parts, ArrayList sentIntents, ArrayList deliveryIntents) {
     if (TextUtils.isEmpty(destinationAddress)) {
         throw new IllegalArgumentException("Invalid destinationAddress");
     }
     if (parts == null || parts.size() < 1) {
         throw new IllegalArgumentException("Invalid message body");
     }


     if (parts.size() > 1) {
         //长短信发送
         try {
             ISms iccISms = getISmsServiceOrThrow();
             iccISms.sendMultipartText(ActivityThread.currentPackageName(),
                     destinationAddress, scAddress, parts,
                     sentIntents, deliveryIntents);
         } catch (RemoteException ex) {
         }
     } else {
         //普通短信发送
         PendingIntent sentIntent = null;
         PendingIntent deliveryIntent = null;
         if (sentIntents != null && sentIntents.size() > 0) {
             sentIntent = sentIntents.get(0);
         }
         if (deliveryIntents != null && deliveryIntents.size() > 0) {
             deliveryIntent = deliveryIntents.get(0);
         }
         sendTextMessage(destinationAddress, scAddress, parts.get(0),
                 sentIntent, deliveryIntent);
     }
 }

        在上面的流程中 区分了长短信和普通短信的流程，我们目前只分析普通短消息，继续看sendTextMessage()：

 public void sendTextMessage( String destinationAddress, String scAddress, String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
     if (TextUtils.isEmpty(destinationAddress)) {
         throw new IllegalArgumentException("Invalid destinationAddress");
     }


     if (TextUtils.isEmpty(text)) {
         throw new IllegalArgumentException("Invalid message body");
     }


     try {
         //继续
         ISms iccISms = getISmsServiceOrThrow();
         iccISms.sendText(ActivityThread.currentPackageName(), destinationAddress, scAddress, text, sentIntent, deliveryIntent);
     } catch (RemoteException ex) {
     }
 }

        到这里，SmsMessage通过调用iccISms对象的sendText()方法将短信继续传递，而SmsMessage的流程就此结束。

五、发送单条短信

        上面的iccISms对象是UiccSmsController的客户端：

 private static ISms getISmsService() {
     return ISms.Stub.asInterface(ServiceManager.getService("isms"));
 }

        所以接下来我们需要进入UiccSmsController的流程中分析：

 @UiccSmsController.java
 public void sendText(String callingPackage, String destAddr, String scAddr, String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
     sendTextForSubscriber(getPreferredSmsSubscription(), callingPackage, destAddr, scAddr, text, sentIntent, deliveryIntent);
 }
 public void sendTextForSubscriber(long subId, String callingPackage, String destAddr, String scAddr, String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
     IccSmsInterfaceManager iccSmsIntMgr = getIccSmsInterfaceManager(subId);
     if (iccSmsIntMgr != null) {
         //通过IccSmsInterfaceManager发送短信
         iccSmsIntMgr.sendText(callingPackage, destAddr, scAddr, text, sentIntent, deliveryIntent);
     } else {
     }
 }

        在上面的UiccSmsController中将任务交给IccSmsInterfaceManager来继续处理。
        IccSmsInterfaceManager这个类没有父类，他在创建PhoneProxy的时候进行初始化，其 作用是把请求发送给相应的处理者。比如对于sendText()将会转交给ImsSMSDispatcher来实现。

 @IccSmsInterfaceManager.java
 public void sendText(String callingPackage, String destAddr, String scAddr, String text, PendingIntent sentIntent, PendingIntent deliveryIntent) {
     //是否声明了发短信的权限
     mPhone.getContext().enforceCallingPermission( Manifest.permission.SEND_SMS, "Sending SMS message");
     //该操作是否被用户允许
     if (mAppOps.noteOp(AppOpsManager.OP_SEND_SMS, Binder.getCallingUid(), callingPackage) != AppOpsManager.MODE_ALLOWED) {
         return;
     }
     //调用ImsSMSDispatcher发送
     destAddr = filterDestAddress(destAddr);
     mDispatcher.sendText(destAddr, scAddr, text, sentIntent, deliveryIntent, null, callingPackage);
 }

        在上面这个过程中，先进行两级权限检查，然后通过ImsSMSDispatcher发送信息。
        SMSDispatcher总共派生出三个子类：CdmaSMSDispatcher、GsmSMSDispatcher、ImsSMSDispatcher，在IccSmsInterfaceManager创建时只创建ImsSMSDispatcher，而在ImsSMSDispatcher创建过程中会对创建其他两种制式的SMSDispatcher，IccSmsInterfaceManager把请求发送给ImsSMSDispatcher后，由ImsSMSDispatcher根据当前网络状态选择使用CdmaSMSDispatcher还是GsmSMSDispatcher。

 @ImsSMSDispatcher.java
 protected void sendText(String destAddr, String scAddr, String text, PendingIntent sentIntent, PendingIntent deliveryIntent, Uri messageUri, String callingPkg) {
     //根据当前网络类型发送，我们只分析GSM
     if (isCdmaMo()) {
         mCdmaDispatcher.sendText(destAddr, scAddr,
                 text, sentIntent, deliveryIntent, messageUri, callingPkg);
     } else {
         mGsmDispatcher.sendText(destAddr, scAddr,
                 text, sentIntent, deliveryIntent, messageUri, callingPkg);
     }
 }

        在上面的过程中，根据当前网络环境使用不同的SMSDispatcher，对于GSM网络来说，当前使用的是GsmSMSDispatcher对象。
        这是Framework层与RILJ最接近的对象，他将请求发送给RILJ。

 @GsmSMSDispatcher.java
 protected void sendText(String destAddr, String scAddr, String text, PendingIntent sentIntent, PendingIntent deliveryIntent, Uri messageUri, String callingPkg) {
     //对短信内容进行编码
     SmsMessage.SubmitPdu pdu = SmsMessage.getSubmitPdu( scAddr, destAddr, text, (deliveryIntent != null));
     if (pdu != null) {
         if (messageUri == null) {
             if (SmsApplication.shouldWriteMessageForPackage(callingPkg, mContext)) {
                 //写入发件箱
                 messageUri = writeOutboxMessage(
                         getSubId(),
                         destAddr,
                         text,
                         deliveryIntent != null,
                         callingPkg);
             }
         } else {
             //移到发件箱
             moveToOutbox(getSubId(), messageUri, callingPkg);
         }
         HashMap map = getSmsTrackerMap(destAddr, scAddr, text, pdu);
         //发送
         SmsTracker tracker = getSmsTracker(map, sentIntent, deliveryIntent, getFormat(), messageUri, false);
         sendRawPdu(tracker);
     } else {
     }
 }

        在上面的过程中，对短消息内容进行编码，然后把短消息写入(或移入)发件箱，然后利用当前的发地址、收地址、文本、附加Intent等信息创建SmsTracker对象，然后调用sendRawPdu()，这个方法是在GsmSMSDispatcher的父类SMSDispatcher中实现的：

 @SMSDispatcher.java
 protected void sendRawPdu(SmsTracker tracker) {
     HashMap map = tracker.mData;
     byte pdu[] = (byte[]) map.get("pdu");


     if (mSmsSendDisabled) {
         tracker.onFailed(mContext, RESULT_ERROR_NO_SERVICE, 0/*errorCode*/);
         return;
     }
     if (pdu == null) {
         tracker.onFailed(mContext, RESULT_ERROR_NULL_PDU, 0/*errorCode*/);
         return;
     }
     PackageManager pm = mContext.getPackageManager();
     String[] packageNames = pm.getPackagesForUid(Binder.getCallingUid());


     if (packageNames == null || packageNames.length == 0) {
         // Refuse to send SMS if we can't get the calling package name.
         tracker.onFailed(mContext, RESULT_ERROR_GENERIC_FAILURE, 0/*errorCode*/);
         return;
     }


     // Get package info via packagemanager
     PackageInfo appInfo;
     try {
         // XXX this is lossy- apps can share a UID
         appInfo = pm.getPackageInfo(packageNames[0], PackageManager.GET_SIGNATURES);
     } catch (PackageManager.NameNotFoundException e) {
         Rlog.e(TAG, "Can't get calling app package info: refusing to send SMS");
         tracker.onFailed(mContext, RESULT_ERROR_GENERIC_FAILURE, 0/*errorCode*/);
         return;
     }


     // checkDestination() returns true if the destination is not a premium short code or the
     // sending app is approved to send to short codes. Otherwise, a message is sent to our
     // handler with the SmsTracker to request user confirmation before sending.
     if (checkDestination(tracker)) {
         // check for excessive outgoing SMS usage by this app
         if (!mUsageMonitor.check(appInfo.packageName, SINGLE_PART_SMS)) {
             sendMessage(obtainMessage(EVENT_SEND_LIMIT_REACHED_CONFIRMATION, tracker));
             return;
         }
         //发送
         sendSms(tracker);
     }
 }

        这里会对要发送的信息以及当前环境进行检测，然后进入sendSms()流程，这个方法又回到了GsmSMSDispatcher中实现：

 @GsmSMSDispatcher.java
 protected void sendSms(SmsTracker tracker) {
     HashMap map = tracker.mData;
     byte pdu[] = (byte[]) map.get("pdu");


     if (tracker.mRetryCount > 0) {
         // per TS 23.040 Section 9.2.3.6:  If TP-MTI SMS-SUBMIT (0x01) type
         //   TP-RD (bit 2) is 1 for retry
         //   and TP-MR is set to previously failed sms TP-MR
         if (((0x01 & pdu[0]) == 0x01)) {
             pdu[0] |= 0x04; // TP-RD
             pdu[1] = (byte) tracker.mMessageRef; // TP-MR
         }
     }


     // Send SMS via the carrier app.
     BroadcastReceiver resultReceiver = new SMSDispatcherReceiver(tracker);


     Intent intent = new Intent(Intents.SMS_SEND_ACTION);
     String carrierPackage = getCarrierAppPackageName(intent);
     if (carrierPackage != null) {
         intent.setPackage(carrierPackage);
         intent.putExtra("pdu", pdu);
         intent.putExtra("smsc", (byte[]) map.get("smsc"));
         intent.putExtra("format", getFormat());
         if (tracker.mSmsHeader != null && tracker.mSmsHeader.concatRef != null) {
             SmsHeader.ConcatRef concatRef = tracker.mSmsHeader.concatRef;
             intent.putExtra("concat.refNumber", concatRef.refNumber);
             intent.putExtra("concat.seqNumber", concatRef.seqNumber);
             intent.putExtra("concat.msgCount", concatRef.msgCount);
         }
         intent.addFlags(Intent.FLAG_RECEIVER_NO_ABORT);
         Rlog.d(TAG, "Sending SMS by carrier app.");
         mContext.sendOrderedBroadcast(intent, android.Manifest.permission.RECEIVE_SMS,
                 AppOpsManager.OP_RECEIVE_SMS, resultReceiver,
                 null, Activity.RESULT_CANCELED, null, null);
     } else {
         //发送
         sendSmsByPstn(tracker);
     }
 }

        然后来看sendSmsByPstn():

 protected void sendSmsByPstn(SmsTracker tracker) {
     int ss = mPhone.getServiceState().getState();
     if (!isIms() && ss != ServiceState.STATE_IN_SERVICE) {
         tracker.onFailed(mContext, getNotInServiceError(ss), 0/*errorCode*/);
         return;
     }
     //拿到SmsTracker中保存的信息
     HashMap map = tracker.mData;


     byte smsc[] = (byte[]) map.get("smsc");
     byte[] pdu = (byte[]) map.get("pdu");
     Message reply = obtainMessage(EVENT_SEND_SMS_COMPLETE, tracker);


     if (0 == tracker.mImsRetry && !isIms()) {
         if (tracker.mRetryCount > 0) {
             if (((0x01 & pdu[0]) == 0x01)) {
                 pdu[0] |= 0x04; // TP-RD
                 pdu[1] = (byte) tracker.mMessageRef; // TP-MR
             }
         }
         if (tracker.mRetryCount == 0 && tracker.mExpectMore) {
             //调用RILJ发送短信
             mCi.sendSMSExpectMore(IccUtils.bytesToHexString(smsc),
                     IccUtils.bytesToHexString(pdu), reply);
         } else {
             mCi.sendSMS(IccUtils.bytesToHexString(smsc),
                     IccUtils.bytesToHexString(pdu), reply);
         }
     } else {
         //通过IMS发送短信
         mCi.sendImsGsmSms(IccUtils.bytesToHexString(smsc),
                 IccUtils.bytesToHexString(pdu), tracker.mImsRetry,
                 tracker.mMessageRef, reply);
         // increment it here, so in case of SMS_FAIL_RETRY over IMS
         // next retry will be sent using IMS request again.
         tracker.mImsRetry++;
     }
 }

        在上面的发送之前，将SmsTracker中的内容解析出来，通过RILJ发送出去。并且注册了该请求的回应消息EVENT_SEND_SMS_COMPLETE，用于处理短信接收时的流程。

        以上就是普通单收件人，短信的发送流程。

        整个过程的流程图如下：

        下一节来介绍长短信的发送流程。

Source: http://blog.csdn.net/u010961631/article/details/50272705