Android短彩信源码解析-短信发送流程（一）

转载请注明出处：http://blog.csdn.net/droyon/article/details/10194591

源码版本来自：Android4.0.3

忙了两三个月，终于有时间可以写点东西了。

有人问我怎么了解原生应用的流程，可能每个人有最适合每个人的方法，现将我的方法说一下，供大家参考：

1、通过DEBUG，DEBUG可以了解每一步代码做了什么，而且可以看到堆栈执行过程。

2、通过打Log的方式。在自己不了解的流程模块打大量的log信息，根据log信息，摸清“模块”的底细。

上述两种方式都需要足够的耐心，但是逐渐接触谜团的真相的过程，确实很享受。好奇心是程序猿，攻城狮的朋友。

 

相关文章：

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2、短信发送framework层逻辑

3、短信发送pdu包压缩解析

---------------------------------------------------------------

现将短信发送的流程整理一下，不当之处请大家斧正。

短信发送大体可以分为下面三个阶段：

我们现在详细叙述一下：

1、短信发送上层逻辑流程

这个界面叫做“会话信息列表界面”，这个界面保存了短彩信所有的会话条目

（会话：英文名Thread，一条会话会记录当前会话内的短信往来信息，例如图片内的10086会话）

点击左下角的新建按钮，那么我们就会进入下面的这个界面：

这个界面叫做“信息列表界面”，它记录了会话内短信往来的所有条目。信息条目按照时间倒序排列：最新的信息条目显示在列表最下方。

我们的短信流程就从这个界面开始，当我们输入完要编辑的信息，点击右下角的发送按钮。

类名：ComposeMessageActivity.java

点击事件：

@Override
    public void onClick(View v) {
        if ((v == mSendButtonSms || v == mSendButtonMms) && isPreparedForSending()) {
            confirmSendMessageIfNeeded();
        } else if ((v == mRecipientsPicker)) {
            launchMultiplePhonePicker();
        }
    }

方法堆栈进入confirmSendMessageIfNeeded，让我们看看confirmSendMessageIfNeeded（）方法：

private void confirmSendMessageIfNeeded() {
        if (!isRecipientsEditorVisible()) {
            sendMessage(true);
            return;
        }

        boolean isMms = mWorkingMessage.requiresMms();
        if (mRecipientsEditor.hasInvalidRecipient(isMms)) {
            if (mRecipientsEditor.hasValidRecipient(isMms)) {
                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 {
                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 {
            // The recipients editor is still open. Make sure we use what's showing there
            // as the destination.
            ContactList contacts = mRecipientsEditor.constructContactsFromInput(false);
            mDebugRecipients = contacts.serialize();
            sendMessage(true);
        }
    }

首先判断联系人输入框是否可见，如果不可见，那么可以直接发送。

然后检查是否有非法的联系人，如果存在，弹出AlertDialog给用户提示。

如果没有非法的联系人，那么直接发送。方法堆栈进入sendMessage（true）

让我们看看sendMessage（true）的逻辑

private void sendMessage(boolean bCheckEcmMode) {
        if (bCheckEcmMode) {
            // TODO: expose this in telephony layer for SDK build
            String inEcm = SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE);
            if (Boolean.parseBoolean(inEcm)) {
                try {
                    startActivityForResult(
                            new Intent(TelephonyIntents.ACTION_SHOW_NOTICE_ECM_BLOCK_OTHERS, null),
                            REQUEST_CODE_ECM_EXIT_DIALOG);
                    return;
                } catch (ActivityNotFoundException e) {
                    // continue to send message
                    Log.e(TAG, "Cannot find EmergencyCallbackModeExitDialog", e);
                }
            }
        }

        if (!mSendingMessage) {
            if (LogTag.SEVERE_WARNING) {
                String sendingRecipients = mConversation.getRecipients().serialize();
                if (!sendingRecipients.equals(mDebugRecipients)) {
                    String workingRecipients = mWorkingMessage.getWorkingRecipients();
                    if (!mDebugRecipients.equals(workingRecipients)) {
                        LogTag.warnPossibleRecipientMismatch("ComposeMessageActivity.sendMessage" +
                                " recipients in window: \"" +
                                mDebugRecipients + "\" differ from recipients from conv: \"" +
                                sendingRecipients + "\" and working recipients: " +
                                workingRecipients, this);
                    }
                }
                sanityCheckConversation();
            }

            // send can change the recipients. Make sure we remove the listeners first and then add
            // them back once the recipient list has settled.
            removeRecipientsListeners();

            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();
        }
    }

传进来的参数为true，也就是检查是否处于紧急模式，如果处于紧急模式，那么进行相关逻辑的处理，并退出发送。

如果当前非处于紧急模式，那么检查当前是否有正在发送的短信，那么在判断mSendDiscreetMode是否为true，如果为true，那么退出此界面。

如果当前不存在正在发送的短信，那么执行 mWorkingMessage.send(mDebugRecipients)。

让我们进入mWorkingMessage.send（）方法：

类名：WorkingMessage.java

public void send(final String recipientsInUI) {
        long origThreadId = mConversation.getThreadId();

        if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
            LogTag.debug("send origThreadId: " + origThreadId);
        }

        removeSubjectIfEmpty(true /* notify */);

        // Get ready to write to disk.
        prepareForSave(true /* notify */);

        // We need the recipient list for both SMS and MMS.
        final Conversation conv = mConversation;
        String msgTxt = mText.toString();//得到发送的内容

        if (requiresMms() || addressContainsEmailToMms(conv, msgTxt)) {//检查当前信息的mMmsState以及是否含有email地址，来判断当前信息是否会转化为彩信
            // uaProfUrl setting in mms_config.xml must be present to send an MMS.
            // However, SMS service will still work in the absence of a uaProfUrl address.
            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;
            }

            // Make local copies of the bits we need for sending a message,
            // because we will be doing it off of the main thread, which will
            // immediately continue on to resetting some of this state.
            final Uri mmsUri = mMessageUri;
            final PduPersister persister = PduPersister.getPduPersister(mActivity);

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

            if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
                LogTag.debug("Send mmsUri: " + mmsUri);
            }

            // Do the dirty work of sending the message off of the main UI thread.
            new Thread(new Runnable() {
                @Override
                public void run() {
                    final SendReq sendReq = makeSendReq(conv, subject);

                    // Make sure the text in slide 0 is no longer holding onto a reference to
                    // the text in the message text box.
                    slideshow.prepareForSend();
                    sendMmsWorker(conv, mmsUri, persister, slideshow, sendReq, textOnly);

                    updateSendStats(conv);
                }
            }, "WorkingMessage.send MMS").start();
        } else {//上面是彩信的逻辑，我们暂且跳过这块，下面的内容，是处理短信的逻辑
            // Same rules apply as above.
            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;
    }

我们主要看一下短信的逻辑部分:

开启一个线程，主线程返回，在新开启的线程里会执行 preSendSmsWorker（）以及updateSendState（）这两个方法。让我们看看这两个方法的内容：

preSendSmsWorker:

private void preSendSmsWorker(Conversation conv, String msgText, String recipientsInUI) {
        // If user tries to send the message, it's a signal the inputted text is what they wanted.
        UserHappinessSignals.userAcceptedImeText(mActivity);

        mStatusListener.onPreMessageSent();

        long origThreadId = conv.getThreadId();

        // Make sure we are still using the correct thread ID for our recipient set.
        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)))) {
            String msg = origThreadId != 0 && origThreadId != threadId ?
                    "WorkingMessage.preSendSmsWorker threadId changed or " +
                    "recipients changed. origThreadId: " +
                    origThreadId + " new threadId: " + threadId +
                    " also mConversation.getThreadId(): " +
                    mConversation.getThreadId()
                :
                    "Recipients in window: \"" +
                    recipientsInUI + "\" differ from recipients from conv: \"" +
                    semiSepRecipients + "\"";

            // Just interrupt the process of sending message if recipient mismatch
            LogTag.warnPossibleRecipientMismatch(msg, mActivity);
        }else {
            // just do a regular send. We're already on a non-ui thread so no need to fire
            // off another thread to do this work.
            sendSmsWorker(msgText, semiSepRecipients, threadId);

            // Be paranoid and clean any draft SMS up.
            deleteDraftSmsMessage(threadId);
        }
    }

在这个方法中，首先 检查/创建 一个threadId，并且调用sendSmsWorker方法。最后删除当前会话内的草稿短信。

比较重要的是两个方法，第一个是conv.ensureThreadId，另一个是sendSmsWorker，我们先来看一下conv.ensureThreadId这个方法：

Conversation.java//保存了和会话信息有关的信息

public synchronized long ensureThreadId() {
        if (DEBUG || DELETEDEBUG) {
            LogTag.debug("ensureThreadId before: " + mThreadId);
        }
        if (mThreadId <= 0) {
            mThreadId = getOrCreateThreadId(mContext, mRecipients);
        }
        if (DEBUG || DELETEDEBUG) {
            LogTag.debug("ensureThreadId after: " + mThreadId);
        }

        return mThreadId;
    }

注意这个方法加了同步锁（synchronized），在这个方法中，我们看到，如果mThreadId不小于0，那么返回mThreadId，如果mThreadId小于0，那么，执行getOrCreateThreadId方法。

这个方法有两个参数，第一个参数为Context，重要的是第二个参数，为当前会话的联系人集合（保存了当前要发送的所有联系人）

private static long getOrCreateThreadId(Context context, ContactList list) {
        HashSet<String> recipients = new HashSet<String>();
        Contact cacheContact = null;
        for (Contact c : list) {
            cacheContact = Contact.get(c.getNumber(), false);
            if (cacheContact != null) {
                recipients.add(cacheContact.getNumber());
            } else {
                recipients.add(c.getNumber());
            }
        }//将联系人的信息导入到recipients中
        synchronized(sDeletingThreadsLock) {//加锁，同步代码快
            if (DELETEDEBUG) {
                ComposeMessageActivity.log("Conversation getOrCreateThreadId for: " +
                        list.formatNamesAndNumbers(",") + " sDeletingThreads: " + sDeletingThreads);
            }
            long now = System.currentTimeMillis();
            while (sDeletingThreads) {
                try {
                    sDeletingThreadsLock.wait(30000);
                } catch (InterruptedException e) {
                }
                if (System.currentTimeMillis() - now > 29000) {
                    // The deleting thread task is stuck or onDeleteComplete wasn't called.
                    // Unjam ourselves.
                    Log.e(TAG, "getOrCreateThreadId timed out waiting for delete to complete",
                            new Exception());
                    sDeletingThreads = false;
                    break;
                }
            }
            long retVal = Threads.getOrCreateThreadId(context, recipients);//重要的是这个方法
            if (DELETEDEBUG || Log.isLoggable(LogTag.APP, Log.VERBOSE)) {
                LogTag.debug("[Conversation] getOrCreateThreadId for (%s) returned %d",
                        recipients, retVal);
            }
            return retVal;
        }
    }

在这个方法中，我们通过执行Threads.getOrCreateTheadId方法来得到或者创建一个ThreadId，并返回。

我们进到Threads.getOrCreateTheadId：

Telephony.java

public static long getOrCreateThreadId(
                Context context, Set<String> recipients) {
            Uri.Builder uriBuilder = THREAD_ID_CONTENT_URI.buildUpon();

            for (String recipient : recipients) {
                if (Mms.isEmailAddress(recipient)) {
                    recipient = Mms.extractAddrSpec(recipient);
                }

                uriBuilder.appendQueryParameter("recipient", recipient);
            }

            Uri uri = uriBuilder.build();
            //if (DEBUG) Rlog.v(TAG, "getOrCreateThreadId uri: " + uri);

            Cursor cursor = SqliteWrapper.query(context, context.getContentResolver(),
                    uri, ID_PROJECTION, null, null, null);
            if (cursor != null) {
                try {
                    if (cursor.moveToFirst()) {
                        return cursor.getLong(0);
                    } else {
                        Rlog.e(TAG, "getOrCreateThreadId returned no rows!");
                    }
                } finally {
                    cursor.close();
                }
            }

            Rlog.e(TAG, "getOrCreateThreadId failed with uri " + uri.toString());
            throw new IllegalArgumentException("Unable to find or allocate a thread ID.");
        }
    }

我们在这个方法汇总只看到了query，并没有看到insert，那么ThreadId在哪里创建的那？
我们跳转到处理SqliteWrapper.query的地方，根据Uri信息，我们找到了处理的逻辑代码：

MmsSmsProvider.java

query方法：

case URI_THREAD_ID:
                List<String> recipients = uri.getQueryParameters("recipient");

                cursor = getThreadId(recipients);
                break;

我们继续深入，进入到getThreadId方法内：

private synchronized Cursor getThreadId(List<String> recipients) {
        Set<Long> addressIds = getAddressIds(recipients);
        String recipientIds = "";

        if (addressIds.size() == 0) {
            Log.e(LOG_TAG, "getThreadId: NO receipients specified -- NOT creating thread",
                    new Exception());
            return null;
        } else if (addressIds.size() == 1) {
            // optimize for size==1, which should be most of the cases
            for (Long addressId : addressIds) {
                recipientIds = Long.toString(addressId);
            }
        } else {
            recipientIds = getSpaceSeparatedNumbers(getSortedSet(addressIds));
        }

        if (Log.isLoggable(LOG_TAG, Log.VERBOSE)) {
            Log.d(LOG_TAG, "getThreadId: recipientIds (selectionArgs) =" +
                    /*recipientIds*/ "xxxxxxx");
        }

        String[] selectionArgs = new String[] { recipientIds };

        SQLiteDatabase db = mOpenHelper.getReadableDatabase();
        db.beginTransaction();
        Cursor cursor = null;
        try {
            // Find the thread with the given recipients
            cursor = db.rawQuery(THREAD_QUERY, selectionArgs);

            if (cursor.getCount() == 0) {
                // No thread with those recipients exists, so create the thread.
                cursor.close();

                Log.d(LOG_TAG, "getThreadId: create new thread_id for recipients " +
                        /*recipients*/ "xxxxxxxx");
                insertThread(recipientIds, recipients.size());

                // The thread was just created, now find it and return it.
                cursor = db.rawQuery(THREAD_QUERY, selectionArgs);
            }
            db.setTransactionSuccessful();
        } catch (Throwable ex) {
            Log.e(LOG_TAG, ex.getMessage(), ex);
        } finally {
            db.endTransaction();
        }

        if (cursor != null && cursor.getCount() > 1) {
            Log.w(LOG_TAG, "getThreadId: why is cursorCount=" + cursor.getCount());
        }
        return cursor;
    }

在这个方法内，我相信大家都找到了答案：

首先：

"SELECT _id FROM threads " + "WHERE recipient_ids=?";

如果查询结果数目为0，也就是说当前联系人不存在任何一个会话（Thread）中，那么我们就执行insertThread创建一个会话。

关于insertThread方法：

private void insertThread(String recipientIds, int numberOfRecipients) {
        ContentValues values = new ContentValues(4);

        long date = System.currentTimeMillis();
        values.put(ThreadsColumns.DATE, date - date % 1000);
        values.put(ThreadsColumns.RECIPIENT_IDS, recipientIds);
        if (numberOfRecipients > 1) {
            values.put(Threads.TYPE, Threads.BROADCAST_THREAD);
        }
        values.put(ThreadsColumns.MESSAGE_COUNT, 0);

        long result = mOpenHelper.getWritableDatabase().insert(TABLE_THREADS, null, values);
        Log.d(LOG_TAG, "insertThread: created new thread_id " + result +
                " for recipientIds " + /*recipientIds*/ "xxxxxxx");

        getContext().getContentResolver().notifyChange(MmsSms.CONTENT_URI, null);
    }

现在我们得到了ThreadId，我们回到我们之前的地方，继续看看在sendSmsWork方法中的逻辑：

WorkingMessage.java

在之前，我们得到了mThreadId，那么我们就可以继续往下走了

sendSmsWorker(msgText, semiSepRecipients, threadId);

            // Be paranoid and clean any draft SMS up.
            deleteDraftSmsMessage(threadId);

我们首先来看看，sendSmsWorker方法：

private void sendSmsWorker(String msgText, String semiSepRecipients, long threadId) {
        String[] dests = TextUtils.split(semiSepRecipients, ";");
        if (LogTag.VERBOSE || Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
            Log.d(LogTag.TRANSACTION, "sendSmsWorker sending message: recipients=" +
                    semiSepRecipients + ", threadId=" + threadId);
        }
        MessageSender sender = new SmsMessageSender(mActivity, dests, msgText, threadId);
        try {
            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);
        }

        mStatusListener.onMessageSent();
        MmsWidgetProvider.notifyDatasetChanged(mActivity);
    }

new一个SmsMessageSender，将联系人的发送地址，发送内容，会话id（threadId）作为参数，然后调用sendMessage方法。

mStatusListener.onMessageSent（）是个回调，告诉ComposeMessageActivity发送完成。

我们主要来看看sendMessage方法。

SmsMessageSender.java

public boolean sendMessage(long token) throws MmsException {
        // In order to send the message one by one, instead of sending now, the message will split,
        // and be put into the queue along with each destinations
        return queueMessage(token);
    }

queueMessage:

private boolean queueMessage(long token) throws MmsException {
        if ((mMessageText == null) || (mNumberOfDests == 0)) {
            // Don't try to send an empty message.
            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);

        for (int i = 0; i < mNumberOfDests; i++) {
            try {
                if (LogTag.DEBUG_SEND) {
                    Log.v(TAG, "queueMessage mDests[i]: " + mDests[i] + " mThreadId: " + mThreadId);
                }
                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);
            }
        }
        // Notify the SmsReceiverService to send the message out
        mContext.sendBroadcast(new Intent(SmsReceiverService.ACTION_SEND_MESSAGE,
                null,
                mContext,
                SmsReceiver.class));
        return false;
    }

检查设置，是否需要发送报告。然后根据mNumberOfDests，执行Sms.addMessageToUri，将信息插入到数据库中。

我们看看插入过程：

Telephony.java

public static Uri addMessageToUri(ContentResolver resolver,
                Uri uri, String address, String body, String subject,
                Long date, boolean read, boolean deliveryReport, long threadId) {
            ContentValues values = new ContentValues(7);

            values.put(ADDRESS, address);
            if (date != null) {
                values.put(DATE, date);
            }
            values.put(READ, read ? Integer.valueOf(1) : Integer.valueOf(0));
            values.put(SUBJECT, subject);
            values.put(BODY, body);
            if (deliveryReport) {
                values.put(STATUS, STATUS_PENDING);
            }
            if (threadId != -1L) {
                values.put(THREAD_ID, threadId);
            }
            return resolver.insert(uri, values);
        }

根据Uri，找到相应的ContentProvider，然后信息会被插入数据库 sms表，信息包括，短信内容，发送时间，信息类型（type = Sms.MESSAGE_TYPE_QUEUED;），等。

sms表上有若干触发器，此处会触发这个触发器：

CREATE TRIGGER sms_update_thread_on_insert AFTER INSERT ON sms BEGIN  UPDATE threads SET    date = (strftime('%s','now') * 1000),     snippet = new.body,     snippet_cs = 0  WHERE threads._id = new.thread_id;   UPDATE threads SET message_count =      (SELECT COUNT(sms._id) FROM sms LEFT JOIN threads       ON threads._id = thread_id      WHERE thread_id = new.thread_id        AND sms.type != 3) +      (SELECT COUNT(pdu._id) FROM pdu LEFT JOIN threads       ON threads._id = thread_id      WHERE thread_id = new.thread_id        AND (m_type=132 OR m_type=130 OR m_type=128)        AND msg_box != 3)   WHERE threads._id = new.thread_id;   UPDATE threads SET read =     CASE (SELECT COUNT(*)          FROM sms          WHERE read = 0            AND thread_id = threads._id)      WHEN 0 THEN 1      ELSE 0    END  WHERE threads._id = new.thread_id; END

意思是在向sms数据表内插入数据后，会更新thread数据表。大家感兴趣的可以自己看一下，大体更新thread表的message_count等。

回到刚才那里，将信息插入到数据库之后，就发起一个广播，然后整个方法堆栈就结束了。

广播发送代码：

mContext.sendBroadcast(new Intent(SmsReceiverService.ACTION_SEND_MESSAGE,
                null,
                mContext,
                SmsReceiver.class));

注意此处的action：

SmsReceiverService.ACTION_SEND_MESSAGE

我们看看广播中的处理逻辑：

SmsReceiver.java

@Override
    public void onReceive(Context context, Intent intent) {
        onReceiveWithPrivilege(context, intent, false);
    }

onReceiveWithPrivilege：

protected void onReceiveWithPrivilege(Context context, Intent intent, boolean privileged) {
        // If 'privileged' is false, it means that the intent was delivered to the base
        // no-permissions receiver class.  If we get an SMS_RECEIVED message that way, it
        // means someone has tried to spoof the message by delivering it outside the normal
        // permission-checked route, so we just ignore it.
        if (!privileged && intent.getAction().equals(Intents.SMS_RECEIVED_ACTION)) {//接受信息的action
            return;
        }

        intent.setClass(context, SmsReceiverService.class);
        intent.putExtra("result", getResultCode());
        beginStartingService(context, intent);//开启service
    }

beginStartingService：

public static void beginStartingService(Context context, Intent intent) {
        synchronized (mStartingServiceSync) {
            if (mStartingService == null) {
                PowerManager pm =
                    (PowerManager)context.getSystemService(Context.POWER_SERVICE);
                mStartingService = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                        "StartingAlertService");
                mStartingService.setReferenceCounted(false);
            }
            mStartingService.acquire();
            context.startService(intent);//开启service
        }
    }

综合来说，这段代码的作用就是在广播中开启了一个service。

我们看看service中的逻辑

smsReceiverService：

public void onCreate() {
        // Temporarily removed for this duplicate message track down.
//        if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE) || LogTag.DEBUG_SEND) {
//            Log.v(TAG, "onCreate");
//        }

        // Start up the thread running the service.  Note that we create a
        // separate thread because the service normally runs in the process's
        // main thread, which we don't want to block.
        HandlerThread thread = new HandlerThread(TAG, Process.THREAD_PRIORITY_BACKGROUND);
        thread.start();

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

首先开启一个新的线程，线程的looper用于处理ServiceHandler中的作业。

public int onStartCommand(Intent intent, int flags, int startId) {
        // Temporarily removed for this duplicate message track down.

        mResultCode = intent != null ? intent.getIntExtra("result", 0) : 0;

        if (mResultCode != 0) {
            Log.v(TAG, "onStart: #" + startId + " mResultCode: " + mResultCode +
                    " = " + translateResultCode(mResultCode));
        }

        Message msg = mServiceHandler.obtainMessage();
        msg.arg1 = startId;
        msg.obj = intent;
        mServiceHandler.sendMessage(msg);
        return Service.START_NOT_STICKY;
    }

将从广播过来的Intent信息包装秤Message作业发送到ServiceHandler中处理：

public void handleMessage(Message msg) {
            int serviceId = msg.arg1;
            Intent intent = (Intent)msg.obj;
            if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
                Log.v(TAG, "handleMessage serviceId: " + serviceId + " intent: " + intent);
            }
            if (intent != null) {
                String action = intent.getAction();

                int error = intent.getIntExtra("errorCode", 0);

                if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
                    Log.v(TAG, "handleMessage action: " + action + " error: " + error);
                }

                if (MESSAGE_SENT_ACTION.equals(intent.getAction())) {
                    handleSmsSent(intent, error);
                } else if (SMS_RECEIVED_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)) {
                    handleSendMessage();
                } else if (ACTION_SEND_INACTIVE_MESSAGE.equals(action)) {
                    handleSendInactiveMessage();
                }
            }
            // NOTE: We MUST not call stopSelf() directly, since we need to
            // make sure the wake lock acquired by AlertReceiver is released.
            SmsReceiver.finishStartingService(SmsReceiverService.this, serviceId);
        }

我们的action：SmsReceiverService.ACTION_SEND_MESSAGE，那么接下来执行：

handleSendMessage（）

private void handleSendMessage() {
        if (!mSending) {
            sendFirstQueuedMessage();
        }
    }

sendFirstQueueMessage：

public synchronized void sendFirstQueuedMessage() {
        boolean success = true;
        // get all the queued messages from the database
        final Uri uri = Uri.parse("content://sms/queued");
        ContentResolver resolver = getContentResolver();
        Cursor c = SqliteWrapper.query(this, resolver, uri,
                        SEND_PROJECTION, null, null, "date ASC");   // date ASC so we send out in
                                                                    // same order the user tried
                                                                    // to send messages.
        if (c != null) {
            try {
                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);

                    SmsMessageSender sender = new SmsSingleRecipientSender(this,
                            address, msgText, threadId, status == Sms.STATUS_PENDING,
                            msgUri);

                    if (LogTag.DEBUG_SEND ||
                            LogTag.VERBOSE ||
                            Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE)) {
                        Log.v(TAG, "sendFirstQueuedMessage " + msgUri +
                                ", address: " + address +
                                ", threadId: " + threadId);
                    }

                    try {
                        sender.sendMessage(SendingProgressTokenManager.NO_TOKEN);;
                        mSending = true;
                    } catch (MmsException e) {
                        Log.e(TAG, "sendFirstQueuedMessage: failed to send message " + msgUri
                                + ", caught ", e);
                        mSending = false;
                        messageFailedToSend(msgUri, SmsManager.RESULT_ERROR_GENERIC_FAILURE);
                        success = false;
                        // Sending current message fails. Try to send more pending messages
                        // if there is any.
                        sendBroadcast(new Intent(SmsReceiverService.ACTION_SEND_MESSAGE,
                                null,
                                this,
                                SmsReceiver.class));
                    }
                }
            } finally {
                c.close();
            }
        }
        if (success) {
            // We successfully sent all the messages in the queue. We don't need to
            // be notified of any service changes any longer.
            unRegisterForServiceStateChanges();
        }
    }

我们刚才将信息插入到sms数据表中，type = Sms.MESSAGE_TYPE_QUEUED，那么此处将这些信息加载上来，遍历发送。

在发送过程中，new一个SmsSingleRecipientSender，将address，msgTest，threadId，是否需要发送报告   ，等作为参数。然后执行此对象的sendMessage方法。

在sendMessage方法中：

public SmsSingleRecipientSender(Context context, String dest, String msgText, long threadId,
            boolean requestDeliveryReport, Uri uri) {
        super(context, null, msgText, threadId);
        mRequestDeliveryReport = requestDeliveryReport;
        mDest = dest;
        mUri = uri;
    }

    public boolean sendMessage(long token) throws MmsException {
        if (LogTag.DEBUG_SEND) {
            Log.v(TAG, "sendMessage token: " + token);
        }
        if (mMessageText == null) {
            // Don't try to send an empty message, and destination should be just
            // one.
            throw new MmsException("Null message body or have multiple destinations.");
        }
        SmsManager smsManager = SmsManager.getDefault();//得到SmsMessager对象
        ArrayList<String> messages = null;
        if ((MmsConfig.getEmailGateway() != null) &&
                (Mms.isEmailAddress(mDest) || MessageUtils.isAlias(mDest))) {
            String msgText;
            msgText = mDest + " " + mMessageText;
            mDest = MmsConfig.getEmailGateway();
            messages = smsManager.divideMessage(msgText);
        } else {
            messages = smsManager.divideMessage(mMessageText);//将短信息分段，是否为长信息
            // remove spaces and dashes from destination number
            // (e.g. "801 555 1212" -> "8015551212")
            // (e.g. "+8211-123-4567" -> "+82111234567")
            mDest = PhoneNumberUtils.stripSeparators(mDest);
            mDest = Conversation.verifySingleRecipient(mContext, mThreadId, mDest);
        }
        int messageCount = messages.size();//得到当前发送内容所占的短信条数

        if (messageCount == 0) {
            // Don't try to send an empty message.
            throw new MmsException("SmsMessageSender.sendMessage: divideMessage returned " +
                    "empty messages. Original message is \"" + mMessageText + "\"");
        }

        boolean moved = Sms.moveMessageToFolder(mContext, mUri, Sms.MESSAGE_TYPE_OUTBOX, 0);//更新短信到发件箱，这个方法挺重要的
        if (!moved) {
            throw new MmsException("SmsMessageSender.sendMessage: couldn't move message " +
                    "to outbox: " + mUri);
        }
        if (LogTag.DEBUG_SEND) {
            Log.v(TAG, "sendMessage mDest: " + mDest + " mRequestDeliveryReport: " +
                    mRequestDeliveryReport);
        }

        ArrayList<PendingIntent> deliveryIntents =  new ArrayList<PendingIntent>(messageCount);//构建两个peddingIntent，用于在信息发送完成之后，回调发送广播。或者在接收到短信状态报告之后回调发送广播
        ArrayList<PendingIntent> sentIntents = new ArrayList<PendingIntent>(messageCount);
        for (int i = 0; i < messageCount; i++) {//遍历发送信息
            if (mRequestDeliveryReport && (i == (messageCount - 1))) {
                // TODO: Fix: It should not be necessary to
                // specify the class in this intent.  Doing that
                // unnecessarily limits customizability.
                deliveryIntents.add(PendingIntent.getBroadcast(
                        mContext, 0,
                        new Intent(
                                MessageStatusReceiver.MESSAGE_STATUS_RECEIVED_ACTION,
                                mUri,
                                mContext,
                                MessageStatusReceiver.class),
                                0));
            } else {
                deliveryIntents.add(null);
            }
            Intent intent  = new Intent(SmsReceiverService.MESSAGE_SENT_ACTION,
                    mUri,
                    mContext,
                    SmsReceiver.class);

            int requestCode = 0;
            if (i == messageCount -1) {
                // Changing the requestCode so that a different pending intent
                // is created for the last fragment with
                // EXTRA_MESSAGE_SENT_SEND_NEXT set to true.
                requestCode = 1;
                intent.putExtra(SmsReceiverService.EXTRA_MESSAGE_SENT_SEND_NEXT, true);
            }
            if (LogTag.DEBUG_SEND) {
                Log.v(TAG, "sendMessage sendIntent: " + intent);
            }
            sentIntents.add(PendingIntent.getBroadcast(mContext, requestCode, intent, 0));
        }
        try {
            smsManager.sendMultipartTextMessage(mDest, mServiceCenter, messages, sentIntents, deliveryIntents);//发送信息的方法。
        } catch (Exception ex) {
            Log.e(TAG, "SmsMessageSender.sendMessage: caught", ex);
            throw new MmsException("SmsMessageSender.sendMessage: caught " + ex +
                    " from SmsManager.sendTextMessage()");
        }
        if (Log.isLoggable(LogTag.TRANSACTION, Log.VERBOSE) || LogTag.DEBUG_SEND) {
            log("sendMessage: address=" + mDest + ", threadId=" + mThreadId +
                    ", uri=" + mUri + ", msgs.count=" + messageCount);
        }
        return false;
    }

总结来说上面的方法做了五件事：

1、得到SmsMessager对象。

2、将信息内容按照GSM/CDMA等制式分段，也就是看需要几条信息将上述信息内容发送出去。因为每条信息有字数限制

3、更新短信类别，更新到发件箱

4、构建两个Peddingintent，这两个Penddingintent用于在信息发送完成之后，或者在接收到短信状态报告之后回调发送广播，这个广播也会在这个service中处理。

5、调用SmsManager发送信息。

以上就是短信发送的上层逻辑，从smsManager.sendMultipartTextMessage之后就要进入到framework层。

我们今天就先介绍短信发送流程的上层逻辑流程，关于后面的两部分，请关注更新。