Android 6.0 Phone MO(去电)流程分析(应用层)

2019-04-13 14:33发布生成海报

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写在前面的话

本文主要分析MO(去电)的流程，研究的代码是Android 6.0的，目前只关注应用层，以GSM为例。

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本文来自http://blog.csdn.net/linyongan

，转载请务必注明出处。

步骤1：当用户点击拨号键盘按钮（DialtactsActivity的floating_action_button）,弹出拨号盘,输入完电话号码，再点击拨号按钮，此时打电话的流程开始，因此打电话流程的入口就在DialpadFragment.java(packagesappsdialersrccomandroiddialerdialpad)的onClick()方法

public void onClick(View view) {
   switch (view.getId()) {
      case R.id.dialpad_floating_action_button:
      mHaptic.vibrate();
      handleDialButtonPressed();
      ...
}

步骤2：在handleDialButtonPressed()方法里，会先判断用户是否已输入号码，假如号码为空，则调用handleDialButtonClickWithEmptyDigits()方法显示上一次拨打过的号码。然后第一次获取到要拨打的number，在这里可以对number做一些判断或者自定义处理。 步骤11,12：在CallIntentProcessor.java的processOutgoingCallIntent()方法里，调用

CallsManager.java的startOutgoingCall()方法创建一个Call实例
Call call = callsManager.startOutgoingCall(handle, phoneAccountHandle, clientExtras);
（这就是Call对象的来源），最后传递给NewOutgoingCallIntentBroadcaster。 步骤13：在NewOutgoingCallIntentBroadcaster.java的processIntent()方法里，第二次获取到要拨打的number，这里也是对number进行一些定制操作的好地方。在这里会调用isPotentialEmergencyNumber()方法判断number是否是潜在的紧急号码，如果是紧急号码会直接走步骤15。

   /**
    * Processes the supplied intent and starts the outgoing call broadcast process relevant to the
    * intent.
    *
    * This method will handle three kinds of actions:
    *
    * - CALL (intent launched by all third party dialers)
    * - CALL_PRIVILEGED (intent launched by system apps e.g. system Dialer, voice Dialer)
    * - CALL_EMERGENCY (intent launched by lock screen emergency dialer)
    *
    * @return {@link DisconnectCause#NOT_DISCONNECTED} if the call succeeded, and an appropriate
    *         {@link DisconnectCause} if the call did not, describing why it failed.
    */
    int processIntent() {
        ...
        //第二次获取到number
        String number = PhoneNumberUtils.getNumberFromIntent(intent, mContext);
        //判断是不是EmergencyNumber
        final boolean isPotentialEmergencyNumber = isPotentialEmergencyNumber(number);
        Log.v(this, "isPotentialEmergencyNumber = %s", isPotentialEmergencyNumber);

        // True for certain types of numbers that are not intended to be intercepted or modified
        // by third parties (e.g. emergency numbers).
        boolean callImmediately = false;

        if (Intent.ACTION_CALL.equals(action)) {
            if (isPotentialEmergencyNumber) {
                if (!mIsDefaultOrSystemPhoneApp) {//拦截第三方软件拨打的紧急号码
                    Log.w(this, "Cannot call potential emergency number %s with CALL Intent %s "
                            + "unless caller is system or default dialer.", number, intent);
                    launchSystemDialer(intent.getData());//弹出系统拨号盘
                    return DisconnectCause.OUTGOING_CANCELED;
                } else {
                    callImmediately = true;//紧急电话的标志
                }
            }
        } else if (Intent.ACTION_CALL_EMERGENCY.equals(action)) {
            if (!isPotentialEmergencyNumber) {//拦截在紧急拨号盘拨打的非紧急电话
                Log.w(this, "Cannot call non-potential-emergency number %s with EMERGENCY_CALL "
                        + "Intent %s.", number, intent);
                return DisconnectCause.OUTGOING_CANCELED;
            }
            callImmediately = true; //紧急电话的标志
        } else {
            Log.w(this, "Unhandled Intent %s. Ignoring and not placing call.", intent);
            return DisconnectCause.INVALID_NUMBER;
        }

        if (callImmediately) {//处理紧急号码
            Log.i(this, "Placing call immediately instead of waiting for "
                    + " OutgoingCallBroadcastReceiver: %s", intent);
            String scheme = isUriNumber ? PhoneAccount.SCHEME_SIP : PhoneAccount.SCHEME_TEL;
            boolean speakerphoneOn = mIntent.getBooleanExtra(
                    TelecomManager.EXTRA_START_CALL_WITH_SPEAKERPHONE, false);
            int videoState = mIntent.getIntExtra(
                    TelecomManager.EXTRA_START_CALL_WITH_VIDEO_STATE,
                    VideoProfile.STATE_AUDIO_ONLY);
            mCallsManager.placeOutgoingCall(mCall, Uri.fromParts(scheme, number, null), null,
                    speakerphoneOn, videoState);//快速处理紧急电话，但是并不return。

            // Don't return but instead continue and send the ACTION_NEW_OUTGOING_CALL broadcast
            // so that third parties can still inspect (but not intercept) the outgoing call. When
            // the broadcast finally reaches the OutgoingCallBroadcastReceiver, we'll know not to
            // initiate the call again because of the presence of the EXTRA_ALREADY_CALLED extra.
        }

        Log.i(this, "Sending NewOutgoingCallBroadcast for %s", mCall);
        //普通电话走这里
        if (isSkipSchemaParsing) {
            broadcastIntent(intent, handle.toString(), !callImmediately);
        } else {
            broadcastIntent(intent, number, !callImmediately);
        }
        return DisconnectCause.NOT_DISCONNECTED;
    }

步骤15：在这里调用了

CallsManage.java的placeOutgoingCall()方法，在这里会调用TelephonyUtil.java的shouldProcessAsEmergency()方法判断是不是紧急拨号,在这里也可以对紧急号码做定制。

 /**
  * Attempts to issue/connect the specified call.
  *
  * @param handle Handle to connect the call with.
  * @param gatewayInfo Optional gateway information that can be used to route the call to the
  *        actual dialed handle via a gateway provider. May be null.
  * @param speakerphoneOn Whether or not to turn the speakerphone on once the call connects.
  * @param videoState The desired video state for the outgoing call.
  */
  void placeOutgoingCall(Call call, Uri handle, GatewayInfo gatewayInfo, boolean speakerphoneOn,
            int videoState) {
        //判断是不是紧急电话
        boolean isEmergencyCall = TelephonyUtil.shouldProcessAsEmergency(mContext,
                call.getHandle());
        ……
        if (isEmergencyCall) {
            // Emergency -- CreateConnectionProcessor will choose accounts automatically
            call.setTargetPhoneAccount(null);
        }

        if (call.getTargetPhoneAccount() != null || isEmergencyCall) {
            if (!isEmergencyCall) {
                updateLchStatus(call.getTargetPhoneAccount().getId());
            }
            // If the account has been set, proceed to place the outgoing call.
            // Otherwise the connection will be initiated when the account is set by the user.
            call.startCreateConnection(mPhoneAccountRegistrar);
        }    }
}

步骤16： call实例被传送到这里，终于派上用场了，进入

Call.java的startCreateConnection()方法

 /**
  * Starts the create connection sequence. Upon completion, there should exist an active
  * connection through a connection service (or the call will have failed).
  *
  * @param phoneAccountRegistrar The phone account registrar.
  */
 void startCreateConnection(PhoneAccountRegistrar phoneAccountRegistrar) {
   Preconditions.checkState(mCreateConnectionProcessor == null);
   mCreateConnectionProcessor = new CreateConnectionProcessor(this, mRepository, this,
   phoneAccountRegistrar, mContext);
   mCreateConnectionProcessor.process();
}

步骤17和18：继续把Call传递给

CreateConnectionProcessor.java，并且new一个CreateConnectionProcessor实例，调用它的process()方法，通过attemptNextPhoneAccount()方法，调用到

service.createConnection，这个service的类型是ConnectionServiceWrapper，它是IConnectionService的子类

private void attemptNextPhoneAccount() {
   ...
   if (mResponse != null && attempt != null) {
     Log.i(this, "Trying attempt %s", attempt);
     ConnectionServiceWrapper service = mRepository.getService(
                            attempt.connectionManagerPhoneAccount.getComponentName());
    if (service == null) {
        Log.i(this, "Found no connection service for attempt %s", attempt);
        attemptNextPhoneAccount();
    } else {
    mCall.setConnectionManagerPhoneAccount(attempt.connectionManagerPhoneAccount);
    mCall.setTargetPhoneAccount(attempt.targetPhoneAccount);
    mCall.setConnectionService(service);
    Log.i(this, "Attempting to call from %s", service.getComponentName());
    service.createConnection(mCall, new Response(service));
    }
  } 
}

这样的话，Call对象就被传递到ConnectionServiceWrapper里了。（读者最好先学习一下AIDL相关知识再继续阅读）
步骤20，21，22：这里调用了ConnectionServiceWrapper的父类ServiceBinder的bind()方法，先new一个ServiceConnection对象，然后绑定一个远程服务端服务。如果绑定成功的话，在ServiceBinder的内部类ServiceBinderConnection的onServiceConnected()方法就被调用。
在这里做了两件事：
1、步骤23和24：通过setBinder()方法，回调ConnectionServiceWrapper的setServiceInterface()方法，通过mServiceInterface = IConnectionService.Stub.asInterface(binder);
这行代码获取一个远程服务端的对象mServiceInterface 。
2、步骤25和26：再通过调用handleSuccessfulConnection()方法回调callback 的onSuccess()方法，也就又回到ConnectionServiceWrapper的createConnection()方法里。
步骤27：最后通过这一行mServiceInterface.createConnection();
，调用

ConnectionService.java里mBinder的createConnection()方法。

private final IBinder mBinder = new IConnectionService.Stub() {
    ...
    @Override
    public void createConnection(PhoneAccountHandle connectionManagerPhoneAccount,
                                 String id,ConnectionRequest request,
                                 boolean isIncoming,boolean isUnknown) {
        SomeArgs args = SomeArgs.obtain();
        args.arg1 = connectionManagerPhoneAccount;
        args.arg2 = id;
        args.arg3 = request;
        args.argi1 = isIncoming ? 1 : 0;
        args.argi2 = isUnknown ? 1 : 0;
        mHandler.obtainMessage(MSG_CREATE_CONNECTION, args).sendToTarget();
    }
    ...
}

步骤28：在这里把传进来的参数封装到Message里再发送出去，然后在

ConnectionService.java里mHandler的handleMessage()方法里处理这个Message

private final Handler mHandler = new Handler(Looper.getMainLooper()) {
    @Override
    public void handleMessage(Message msg) {
       switch (msg.what) {
           case MSG_CREATE_CONNECTION: {
               SomeArgs args = (SomeArgs) msg.obj;
               try {
               final PhoneAccountHandle connectionManagerPhoneAccount =
                                (PhoneAccountHandle) args.arg1;
               final String id = (String) args.arg2;
               final ConnectionRequest request = (ConnectionRequest) args.arg3;
               final boolean isIncoming = args.argi1 == 1;
               final boolean isUnknown = args.argi2 == 1;
               if (!mAreAccountsInitialized) {
                   Log.d(this, "Enqueueing pre-init request %s", id);
                   mPreInitializationConnectionRequests.add(new Runnable() {
                   @Override
                   public void run() {
                   createConnection(connectionManagerPhoneAccount,
                                    id,
                                    request,
                                    isIncoming,
                                    isUnknown);
                                }
                   });
                } else {
                   createConnection(connectionManagerPhoneAccount,
                                    id,
                                    request,
                                    isIncoming,
                                    isUnknown);
                   }
                } finally {
                  args.recycle();
                }
            break;
        }
   ...
}

步骤29，30，31：在这里就把Message里的数据取出来，然后传递到ConnectionService的createConnection()方法里。接着onCreateOutgoingConnection()会被调用到，这个方法被TelephonyConnectionService重写，TelephonyConnectionService是ConnectionService的实例，所以进入

TelephonyConnectionService.java的onCreateOutgoingConnection()方法，在这里第三次取出number，会再次判断是不是紧急号码，如果是的话，会turn on radio关闭飞行模式再拨打紧急电话。phone 对象和connection 对象也是在这时候被创建。

public Connection onCreateOutgoingConnection(
            PhoneAccountHandle connectionManagerPhoneAccount,
            final ConnectionRequest request) {
   ...
   // 判断是不是紧急号码
   boolean isEmergencyNumber = PhoneNumberUtils.isLocalEmergencyNumber(this, number);
   // Get the right phone object from the account data passed in.
   //创建phone 对象
   final Phone phone = getPhoneForAccount(request.getAccountHandle(), isEmergencyNumber);
   if (phone == null) {
     Log.d(this, "onCreateOutgoingConnection, phone is null");
     return Connection.createFailedConnection(
                DisconnectCauseUtil.toTelecomDisconnectCause(
                android.telephony.DisconnectCause.OUT_OF_SERVICE, "Phone is null"));
   }
   ...
   //创建connection对象
   final TelephonyConnection connection =
                createConnectionFor(phone, null, true /* isOutgoing */, null);
   if (connection == null) {
      return Connection.createFailedConnection(
                    DisconnectCauseUtil.toTelecomDisconnectCause(
                    android.telephony.DisconnectCause.OUTGOING_FAILURE,
                    "Invalid phone type"));
   }
   connection.setAddress(handle, PhoneConstants.PRESENTATION_ALLOWED);
   connection.setInitializing();
   connection.setVideoState(request.getVideoState());

   if (useEmergencyCallHelper) {
       if (mEmergencyCallHelper == null) {
                mEmergencyCallHelper = new EmergencyCallHelper(this);
            }
           //打开Radio，关闭飞行模式
            mEmergencyCallHelper.startTurnOnRadioSequence(phone,
                    new EmergencyCallHelper.Callback() {
                        @Override
                        public void onComplete(boolean isRadioReady) {
                            if (connection.getState() == Connection.STATE_DISCONNECTED) {
                                // If the connection has already been disconnected, do nothing.
                            } else if (isRadioReady) {
                            //Radio已被打开，可以拨打紧急电话
                                connection.setInitialized();
                                placeOutgoingConnection(connection, phone, request);
                            } else {
                                Log.d(this, "onCreateOutgoingConnection, failed to turn on radio");
                                connection.setDisconnected(
                                        DisconnectCauseUtil.toTelecomDisconnectCause(
                                                android.telephony.DisconnectCause.POWER_OFF,
                                                "Failed to turn on radio."));
                                connection.destroy();
                            }
                        }
                    });

        } else {
            placeOutgoingConnection(connection, phone, request);
        }   return connection;
}

步骤32：在步骤30createConnection()方法的最后，调用了ConnectionServiceAdapter.java的handleCreateConnectionComplete()方法继续执行了一段流程，在创建Connection完成之后，会把Call的状态从CONNECTING更新为 DIALING。此段流程就不详说了。 步骤34～37：紧接着步骤33，最后通过phone.dial进行拨号，之后的流程就进入到Framework层了。
本文就写到这里。

如果想继续了解Framework层的流程，请看《Android 5.1 Phone MO(去电)流程分析(Framework层) 》