Android7.0 Phone应用源码分析（四） phone挂断流程分析

接上篇博文：Android7.0 Phone应用源码分析（三） phone拒接流程分析

今天我们再来分析一下电话挂断流程

电话挂断分为本地挂断和远程挂断，针对这两种情况各做分析

先来看下本地挂断电话的时序图：

 

步骤1：点击通话界面的挂断按钮，会调用到CallCardPresenter的endCallClicked方法，请看CallCardFragment里挂断按钮的监听事件

com.android.incallui.CallCardFragment
 public void onViewCreated(View view, Bundle savedInstanceState) {
        ...... 

        ......
         mFloatingActionButton.setOnClickListener(new View.OnClickListener() {
             @Override
            public void onClick(View v) {
                getPresenter().endCallClicked();
            }
        });
       
}

com.android.incallui.CallCardPresenter
 public void endCallClicked() {
        if (mPrimary == null) {
            return;
        }

        Log.i(this, "Disconnecting call: " + mPrimary);
        final String callId = mPrimary.getId();
        mPrimary.setState(Call.State.DISCONNECTING);
        CallList.getInstance().onUpdate(mPrimary);
        TelecomAdapter.getInstance().disconnectCall(callId);
 }

这里先把Call的状态设置成DISCONNECTING，然后通过CallList更新UI界面，最后继续挂断流程

步骤2：TelecomAdapter的disconnectCall流程

com.android.incallui.TelecomAdapter
void disconnectCall(String callId) {
        android.telecom.Call call = getTelecomCallById(callId);
        if (call != null) {
            call.disconnect();
        } else {
            Log.e(this, "error disconnectCall, call not in call list " + callId);
        }
 }

通过callid找到对应的Call对象（android.telecom.Call）

步骤3：调用到framework里Call的disconnect方法

android.telecom.Call
 public void disconnect() {
        mInCallAdapter.disconnectCall(mTelecomCallId);
 }

这里mInCallAdapter是android.telecom.InCallAdapter类，与telecom进程通信的代理类

步骤4：InCallAdapter的disconnectCall方法

android.telecom.InCallAdapter
 public void disconnectCall(String callId) {
        try {
            mAdapter.disconnectCall(callId);
        } catch (RemoteException e) {
        }
}

mAdapter就是incallui与telecom通信的AIDL接口

步骤5：跨进程调用进入telecom进程，该AIDL接口具体实现类是InCallAdapter，相同的类名不一样的包名

com.android.server.telecom.InCallAdapter
 public void disconnectCall(String callId) {
        try {
            Log.startSession("ICA.dC", mOwnerComponentName);
            long token = Binder.clearCallingIdentity();
            try {
                synchronized (mLock) {
                    Log.v(this, "disconnectCall: %s", callId);
                    Call call = mCallIdMapper.getCall(callId);
                    if (call != null) {
                        mCallsManager.disconnectCall(call);
                    } else {
                        Log.w(this, "disconnectCall, unknown call id: %s", callId);
                    }
                }
            } finally {
                Binder.restoreCallingIdentity(token);
            }
        } finally {
            Log.endSession();
        }
}

这里同样是根据callid取出对应Call（com.android.server.telecom.Call),最后调用CallsManager的disconnectCall方法传入call

步骤6：CallsManager的disconnectCall方法

com.android.server.telecom.CallsManager
public void disconnectCall(Call call) {
        Log.v(this, "disconnectCall %s", call);

        if (!mCalls.contains(call)) {
            Log.w(this, "Unknown call (%s) asked to disconnect", call);
        } else {
            mLocallyDisconnectingCalls.add(call);
            call.disconnect();
        }
}

将该Call对象加入本地断开Call列表，之后进入Call的disconnect方法

步骤7：Call的disconnect方法

com.android.server.telecom.Call 
public void disconnect() {
        disconnect(false);
 }

public void disconnect(boolean wasViaNewOutgoingCallBroadcaster) {
        Log.event(this, Log.Events.REQUEST_DISCONNECT);

        // Track that the call is now locally disconnecting.
        setLocallyDisconnecting(true);

        if (mState == CallState.NEW || mState == CallState.SELECT_PHONE_ACCOUNT ||
                mState == CallState.CONNECTING) {
            Log.v(this, "Aborting call %s", this);
            abort(wasViaNewOutgoingCallBroadcaster);
        } else if (mState != CallState.ABORTED && mState != CallState.DISCONNECTED) {
            if (mConnectionService == null) {
                Log.e(this, new Exception(), "disconnect() request on a call without a"
                        + " connection service.");
            } else {
                Log.i(this, "Send disconnect to connection service for call: %s", this);
                // The call isn't officially disconnected until the connection service
                // confirms that the call was actually disconnected. Only then is the
                // association between call and connection service severed, see
                // {@link CallsManager#markCallAsDisconnected}.
                mConnectionService.disconnect(this);
            }
        }
 }

setLocallyDisconnecting(true); 先设置是否为本地挂断标志为true

由于mState这时候是CallState.ACTIVE状态，进入mConnectionService的disconnect方法

这里的mConnectionService是ConnectionServiceWrapper类，是telecom与telephony通信的代理类

步骤8：ConnectionServiceWrapper的disconnect方法

com.android.server.telecom.ConnectionServiceWrapper
void disconnect(Call call) {
        final String callId = mCallIdMapper.getCallId(call);
        if (callId != null && isServiceValid("disconnect")) {
            try {
                logOutgoing("disconnect %s", callId);
                mServiceInterface.disconnect(callId);
            } catch (RemoteException e) {
            }
        }
}

这里mServiceInterface就是telephony提供给telecom调用的AIDL接口

步骤9：跨进程调用进入telephony进程，AIDL接口具体实现是其父类ConnectionService的mBinder成员变量

android.telecom.ConnectionService
 private final IBinder mBinder = new IConnectionService.Stub() {
       

        ...... 

        ......

public void disconnect(String callId) {
            mHandler.obtainMessage(MSG_DISCONNECT, callId).sendToTarget();
        }

}

步骤10~13：发送MSG_DISCONNECT消息到队列里处理

private void disconnect(String callId) {
        Log.d(this, "disconnect %s", callId);
        if (mConnectionById.containsKey(callId)) {
            findConnectionForAction(callId, "disconnect").onDisconnect();
        } else {
            findConferenceForAction(callId, "disconnect").onDisconnect();
        }
    }

private Connection findConnectionForAction(String callId, String action) {
        if (mConnectionById.containsKey(callId)) {
            return mConnectionById.get(callId);
        }
        Log.w(this, "%s - Cannot find Connection %s", action, callId);
        return getNullConnection();
    }

根据callid找到对应的connection对象（android.telecom.Connection），调用onDisconnect方法

步骤14，15：TelephonyConnection继承于connection

com.android.services.telephony.TelephonyConnection
 public void onDisconnect() {
        Log.v(this, "onDisconnect");
        hangup(android.telephony.DisconnectCause.LOCAL);
    }

protected void hangup(int telephonyDisconnectCode) {
        if (mOriginalConnection != null) {
            try {
                // Hanging up a ringing call requires that we invoke call.hangup() as opposed to
                // connection.hangup(). Without this change, the party originating the call will not
                // get sent to voicemail if the user opts to reject the call.
                if (isValidRingingCall()) {
                    Call call = getCall();
                    if (call != null) {
                        call.hangup();
                    } else {
                        Log.w(this, "Attempting to hangup a connection without backing call.");
                    }
                } else {
                    // We still prefer to call connection.hangup() for non-ringing calls in order
                    // to support hanging-up specific calls within a conference call. If we invoked
                    // call.hangup() while in a conference, we would end up hanging up the entire
                    // conference call instead of the specific connection.
                    mOriginalConnection.hangup();
                }
            } catch (CallStateException e) {
                Log.e(this, e, "Call to Connection.hangup failed with exception");
            }
        }
    }

设置断开连接类型为DisconnectCause.LOCAL，并调用mOriginalConnection的hangup方法, 实际Connection类是GsmCdmaConnection

步骤16：GsmCdmaConnection的hangup方法

com.android.internal.telephony.GsmCdmaConnection
 public void hangup() throws CallStateException {
        if (!mDisconnected) {
            mOwner.hangup(this);
        } else {
            throw new CallStateException ("disconnected");
        }
 }

这里的mOwner对想是GsmCdmaCallTracker类型

步骤17：GsmCdmaCallTracker的hangup方法

com.android.internal.telephony.GsmCdmaCallTracker
 public void hangup(GsmCdmaConnection conn) throws CallStateException {
        if (conn.mOwner != this) {
            throw new CallStateException ("GsmCdmaConnection " + conn
                                    + "does not belong to GsmCdmaCallTracker " + this);
        }

        if (conn == mPendingMO) {
            // We're hanging up an outgoing call that doesn't have it's
            // GsmCdma index assigned yet

            if (Phone.DEBUG_PHONE) log("hangup: set hangupPendingMO to true");
            mHangupPendingMO = true;
        } else if (!isPhoneTypeGsm()
                && conn.getCall() == mRingingCall
                && mRingingCall.getState() == GsmCdmaCall.State.WAITING) {
            // Handle call waiting hang up case.
            //
            // The ringingCall state will change to IDLE in GsmCdmaCall.detach
            // if the ringing call connection size is 0. We don't specifically
            // set the ringing call state to IDLE here to avoid a race condition
            // where a new call waiting could get a hang up from an old call
            // waiting ringingCall.
            //
            // PhoneApp does the call log itself since only PhoneApp knows
            // the hangup reason is user ignoring or timing out. So conn.onDisconnect()
            // is not called here. Instead, conn.onLocalDisconnect() is called.
            conn.onLocalDisconnect();

            updatePhoneState();
            mPhone.notifyPreciseCallStateChanged();
            return;
        } else {
            try {
                mCi.hangupConnection (conn.getGsmCdmaIndex(), obtainCompleteMessage());
            } catch (CallStateException ex) {
                // Ignore "connection not found"
                // Call may have hung up already
                Rlog.w(LOG_TAG,"GsmCdmaCallTracker WARN: hangup() on absent connection "
                                + conn);
            }
        }

        conn.onHangupLocal();
 }

由于是通话中挂断，这里调用 mCi.hangupConnection (conn.getGsmCdmaIndex(), obtainCompleteMessage());

这里调用conn的getGsmCdmaIndex方法先获取索引

com.android.internal.telephony.GsmCdmaConnection
 getGsmCdmaIndex() throws CallStateException {
        if (mIndex >= 0) {
            return mIndex + 1;
        } else {
            throw new CallStateException ("GsmCdma index not yet assigned");
        }
}

这个索引对应的就是DriveCall里的index值，匹配modem里CallList里对于Call对象

mCi是CommandsInterface即RILJ接口，包装了一个EVENT_OPERATION_COMPLETE回调消息，发送给RIL

步骤18：RIL的hangupConnection方法

com.android.internal.telephony.RIL
public void  hangupConnection (int gsmIndex, Message result) {
        if (RILJ_LOGD) riljLog("hangupConnection: gsmIndex=" + gsmIndex);

        RILRequest rr = RILRequest.obtain(RIL_REQUEST_HANGUP, result);

        if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest) + " " +
                gsmIndex);

        mEventLog.writeRilHangup(rr.mSerial, RIL_REQUEST_HANGUP, gsmIndex);

        rr.mParcel.writeInt(1);
        rr.mParcel.writeInt(gsmIndex);

        send(rr);
 }

给RIL层发送RIL_REQUEST_HANGUP消息并附带index参数

步骤19~23：收到RIL层的回应消息并处理，最后发送回调消息EVENT_OPERATION_COMPLETE给GsmCdmaCallTracker

步骤24：GsmCdmaCallTracker处理回调消息EVENT_OPERATION_COMPLETE

com.android.internal.telephony.GsmCdmaCallTracker 
private void operationComplete() {
        mPendingOperations--;

        if (DBG_POLL) log("operationComplete: pendingOperations=" +
                mPendingOperations + ", needsPoll=" + mNeedsPoll);

        if (mPendingOperations == 0 && mNeedsPoll) {
            mLastRelevantPoll = obtainMessage(EVENT_POLL_CALLS_RESULT);
            mCi.getCurrentCalls(mLastRelevantPoll);
        } else if (mPendingOperations < 0) {
            // this should never happen
            Rlog.e(LOG_TAG,"GsmCdmaCallTracker.pendingOperations < 0");
            mPendingOperations = 0;
        }
    }

这里再次向RIL发送消息主动获取当前Call状态，包装的回调消息为EVENT_POLL_CALLS_RESULT

步骤25~31：RIL返回消息，GsmCdmaCallTracker接收EVENT_POLL_CALLS_RESULT消息并处理

com.android.internal.telephony.GsmCdmaCallTracker 
protected synchronized void handlePollCalls(AsyncResult ar) {
        List polledCalls;

        if (VDBG) log("handlePollCalls");
        if (ar.exception == null) {
            polledCalls = (List)ar.result;
        } else if (isCommandExceptionRadioNotAvailable(ar.exception)) {
            // just a dummy empty ArrayList to cause the loop
            // to hang up all the calls
            polledCalls = new ArrayList();
        } else {
            // Radio probably wasn't ready--try again in a bit
            // But don't keep polling if the channel is closed
            pollCallsAfterDelay();
            return;
        }

        …………

for (int i = 0, curDC = 0, dcSize = polledCalls.size()
                ; i < mConnections.length; i++) {
            GsmCdmaConnection conn = mConnections[i];
            DriverCall dc = null;

            // polledCall list is sparse
            if (curDC < dcSize) {
                dc = (DriverCall) polledCalls.get(curDC);

                if (dc.index == i+1) {
                    curDC++;
                } else {
                    dc = null;
                }
            }

          …………          
            } else if (conn != null && dc == null) {
                if (isPhoneTypeGsm()) {
                    // Connection missing in CLCC response that we were
                    // tracking.
                    mDroppedDuringPoll.add(conn);
                    // Dropped connections are removed from the CallTracker
                    // list but kept in the GsmCdmaCall list
                    mConnections[i] = null;
                } else {
                

           …………      
        for (int i = mDroppedDuringPoll.size() - 1; i >= 0 ; i--) {
            GsmCdmaConnection conn = mDroppedDuringPoll.get(i);
            //CDMA
            boolean wasDisconnected = false;

            if (conn.isIncoming() && conn.getConnectTime() == 0) {
                // Missed or rejected call
                int cause;
                if (conn.mCause == DisconnectCause.LOCAL) {
                    cause = DisconnectCause.INCOMING_REJECTED;
                } else {
                    cause = DisconnectCause.INCOMING_MISSED;
                }

                if (Phone.DEBUG_PHONE) {
                    log("missed/rejected call, conn.cause=" + conn.mCause);
                    log("setting cause to " + cause);
                }
                mDroppedDuringPoll.remove(i);
                hasAnyCallDisconnected |= conn.onDisconnect(cause);
                wasDisconnected = true;
            } else if (conn.mCause == DisconnectCause.LOCAL
                    || conn.mCause == DisconnectCause.INVALID_NUMBER) {
                mDroppedDuringPoll.remove(i);
                hasAnyCallDisconnected |= conn.onDisconnect(conn.mCause);
                wasDisconnected = true;
            }

            if (!isPhoneTypeGsm() && wasDisconnected && unknownConnectionAppeared
                    && conn == newUnknownConnectionCdma) {
                unknownConnectionAppeared = false;
                newUnknownConnectionCdma = null;
            }
        }

        /* Disconnect any pending Handover connections */
        for (Iterator<Connection> it = mHandoverConnections.iterator();
                it.hasNext();) {
            Connection hoConnection = it.next();
            log("handlePollCalls - disconnect hoConn= " + hoConnection +
                    " hoConn.State= " + hoConnection.getState());
            if (hoConnection.getState().isRinging()) {
                hoConnection.onDisconnect(DisconnectCause.INCOMING_MISSED);
            } else {
                hoConnection.onDisconnect(DisconnectCause.NOT_VALID);
            }
            it.remove();
        }

        // Any non-local disconnects: determine cause
        if (mDroppedDuringPoll.size() > 0) {
            mCi.getLastCallFailCause(
                obtainNoPollCompleteMessage(EVENT_GET_LAST_CALL_FAIL_CAUSE));
        }

         …………
        if (VDBG) log("handlePollCalls calling updatePhoneState()");
        updatePhoneState();

        if (unknownConnectionAppeared) {
            if (isPhoneTypeGsm()) {
                for (Connection c : newUnknownConnectionsGsm) {
                    log("Notify unknown for " + c);
                    mPhone.notifyUnknownConnection(c);
                }
            } else {
                mPhone.notifyUnknownConnection(newUnknownConnectionCdma);
            }
        }

        if (hasNonHangupStateChanged || newRinging != null || hasAnyCallDisconnected) {
            mPhone.notifyPreciseCallStateChanged();
        }

        //dumpState();
    }
}

这里是通话断开事件，将connection放入mDroppedDuringPoll列表，由于断开类型是DisconnectCause.LOCAL

直接调用GsmCdmaConnection的onDisconnect方法传入cause参数

步骤32：GsmCdmaConnection的onDisconnect方法

com.android.internal.telephony.GsmCdmaConnection
 public boolean onDisconnect(int cause) {
        boolean changed = false;

        mCause = cause;

        if (!mDisconnected) {
            doDisconnect();

            if (DBG) Rlog.d(LOG_TAG, "onDisconnect: cause=" + cause);

            mOwner.getPhone().notifyDisconnect(this);

            if (mParent != null) {
                changed = mParent.connectionDisconnected(this);
            }

            mOrigConnection = null;
        }
        clearPostDialListeners();
        releaseWakeLock();
        return changed;
  }

doDisconnect方法设置断开时间以及通话时长

private void  doDisconnect() {
        mIndex = -1;
        mDisconnectTime = System.currentTimeMillis();
        mDuration = SystemClock.elapsedRealtime() - mConnectTimeReal;
        mDisconnected = true;
        clearPostDialListeners();
}

最后通知注册者断开事件mOwner.getPhone().notifyDisconnect(this);

步骤33之后的流程就跟上篇讲解phone拒接流程一样，这里就不重复描述了

详见http://www.cnblogs.com/lance2016/p/6391096.html

讲完本地挂断电话的流程，再讲一下远程挂断的流程，先看一下相关的时序图

 

步骤1~4：modem层上报RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED事件，RIL通知EVENT_CALL_STATE_CHANGE消息

步骤5，6，7：GsmCdmaCallTracker处理消息，向RIL发送消息主动获取当前Call状态，包装的回调消息为EVENT_POLL_CALLS_RESULT

com.android.internal.telephony.CallTracker 
protected void pollCallsWhenSafe() {
        mNeedsPoll = true;

        if (checkNoOperationsPending()) {
            mLastRelevantPoll = obtainMessage(EVENT_POLL_CALLS_RESULT);
            mCi.getCurrentCalls(mLastRelevantPoll);
        }
}

步骤8~13：RIL返回消息，GsmCdmaCallTracker接收EVENT_POLL_CALLS_RESULT消息并处理

com.android.internal.telephony.GsmCdmaCallTracker
 protected synchronized void handlePollCalls(AsyncResult ar) {
        List polledCalls;

       …………

if (mDroppedDuringPoll.size() > 0) {
            mCi.getLastCallFailCause(
                obtainNoPollCompleteMessage(EVENT_GET_LAST_CALL_FAIL_CAUSE));
        }

       …………

}

这里跟前面本地挂断的流程差不多，但区别是由于不是本地挂断的cause类型，会主动再向RIL发送消息获取通话断开的cause

包装的回调消息为EVENT_GET_LAST_CALL_FAIL_CAUSE

步骤14：RIL的getLastCallFailCause方法

com.android.internal.telephony.RIL
 public void getLastCallFailCause (Message result) {
        RILRequest rr
                = RILRequest.obtain(RIL_REQUEST_LAST_CALL_FAIL_CAUSE, result);

        if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest));

        send(rr);
 }

向MODEM发送RIL_REQUEST_LAST_CALL_FAIL_CAUSE消息

步骤15~20：modem回应RIL_REQUEST_LAST_CALL_FAIL_CAUSE消息，RIL发送回调消息EVENT_GET_LAST_CALL_FAIL_CAUSE

步骤21：GsmCdmaCallTracker处理消息

com.android.internal.telephony.GsmCdmaCallTracker
 case EVENT_GET_LAST_CALL_FAIL_CAUSE:
                int causeCode;
                String vendorCause = null;
                ar = (AsyncResult)msg.obj;

                operationComplete();

                if (ar.exception != null) {
                    // An exception occurred...just treat the disconnect
                    // cause as "normal"
                    causeCode = CallFailCause.NORMAL_CLEARING;
                    Rlog.i(LOG_TAG,
                            "Exception during getLastCallFailCause, assuming normal disconnect");
                } else {
                    LastCallFailCause failCause = (LastCallFailCause)ar.result;
                    causeCode = failCause.causeCode;
                    vendorCause = failCause.vendorCause;
                }
                // Log the causeCode if its not normal
                if (causeCode == CallFailCause.NO_CIRCUIT_AVAIL ||
                    causeCode == CallFailCause.TEMPORARY_FAILURE ||
                    causeCode == CallFailCause.SWITCHING_CONGESTION ||
                    causeCode == CallFailCause.CHANNEL_NOT_AVAIL ||
                    causeCode == CallFailCause.QOS_NOT_AVAIL ||
                    causeCode == CallFailCause.BEARER_NOT_AVAIL ||
                    causeCode == CallFailCause.ERROR_UNSPECIFIED) {

                    CellLocation loc = mPhone.getCellLocation();
                    int cid = -1;
                    if (loc != null) {
                        if (isPhoneTypeGsm()) {
                            cid = ((GsmCellLocation)loc).getCid();
                        } else {
                            cid = ((CdmaCellLocation)loc).getBaseStationId();
                        }
                    }
                    EventLog.writeEvent(EventLogTags.CALL_DROP, causeCode, cid,
                            TelephonyManager.getDefault().getNetworkType());
                }

                for (int i = 0, s = mDroppedDuringPoll.size(); i < s ; i++) {
                    GsmCdmaConnection conn = mDroppedDuringPoll.get(i);

                    conn.onRemoteDisconnect(causeCode, vendorCause);
                }

                updatePhoneState();

                mPhone.notifyPreciseCallStateChanged();
                mDroppedDuringPoll.clear();
            break;

RIL在处理RIL_REQUEST_LAST_CALL_FAIL_CAUSE消息时将结果放入LastCallFailCause对象，传递给GsmCdmaCallTracker

GsmCdmaCallTracker得到结果，其中causeCode值就是断开原因，接着调用GsmCdmaConnection的onRemoteDisconnect方法

步骤22：GsmCdmaConnection的onRemoteDisconnect方法

com.android.internal.telephony.GsmCdmaConnection
void onRemoteDisconnect(int causeCode, String vendorCause) {
        this.mPreciseCause = causeCode;
        this.mVendorCause = vendorCause;
        onDisconnect(disconnectCauseFromCode(causeCode));
    }

这里通过disconnectCauseFromCode方法将causeCode值转化为DisconnectCause值

int disconnectCauseFromCode(int causeCode) {
        /**
         * See 22.001 Annex F.4 for mapping of cause codes
         * to local tones
         */

        switch (causeCode) {
            case CallFailCause.USER_BUSY:
                return DisconnectCause.BUSY;

            case CallFailCause.NO_CIRCUIT_AVAIL:
            case CallFailCause.TEMPORARY_FAILURE:
            case CallFailCause.SWITCHING_CONGESTION:
            case CallFailCause.CHANNEL_NOT_AVAIL:
            case CallFailCause.QOS_NOT_AVAIL:
            case CallFailCause.BEARER_NOT_AVAIL:
                return DisconnectCause.CONGESTION;

            case CallFailCause.ACM_LIMIT_EXCEEDED:
                return DisconnectCause.LIMIT_EXCEEDED;

            case CallFailCause.CALL_BARRED:
                return DisconnectCause.CALL_BARRED;

            case CallFailCause.FDN_BLOCKED:
                return DisconnectCause.FDN_BLOCKED;

            case CallFailCause.UNOBTAINABLE_NUMBER:
                return DisconnectCause.UNOBTAINABLE_NUMBER;

            case CallFailCause.DIAL_MODIFIED_TO_USSD:
                return DisconnectCause.DIAL_MODIFIED_TO_USSD;

            case CallFailCause.DIAL_MODIFIED_TO_SS:
                return DisconnectCause.DIAL_MODIFIED_TO_SS;

            case CallFailCause.DIAL_MODIFIED_TO_DIAL:
                return DisconnectCause.DIAL_MODIFIED_TO_DIAL;

            case CallFailCause.CDMA_LOCKED_UNTIL_POWER_CYCLE:
                return DisconnectCause.CDMA_LOCKED_UNTIL_POWER_CYCLE;

            case CallFailCause.CDMA_DROP:
                return DisconnectCause.CDMA_DROP;

            case CallFailCause.CDMA_INTERCEPT:
                return DisconnectCause.CDMA_INTERCEPT;

            case CallFailCause.CDMA_REORDER:
                return DisconnectCause.CDMA_REORDER;

            case CallFailCause.CDMA_SO_REJECT:
                return DisconnectCause.CDMA_SO_REJECT;

            case CallFailCause.CDMA_RETRY_ORDER:
                return DisconnectCause.CDMA_RETRY_ORDER;

            case CallFailCause.CDMA_ACCESS_FAILURE:
                return DisconnectCause.CDMA_ACCESS_FAILURE;

            case CallFailCause.CDMA_PREEMPTED:
                return DisconnectCause.CDMA_PREEMPTED;

            case CallFailCause.CDMA_NOT_EMERGENCY:
                return DisconnectCause.CDMA_NOT_EMERGENCY;

            case CallFailCause.CDMA_ACCESS_BLOCKED:
                return DisconnectCause.CDMA_ACCESS_BLOCKED;

            case CallFailCause.ERROR_UNSPECIFIED:
            case CallFailCause.NORMAL_CLEARING:
            default:
                GsmCdmaPhone phone = mOwner.getPhone();
                int serviceState = phone.getServiceState().getState();
                UiccCardApplication cardApp = phone.getUiccCardApplication();
                AppState uiccAppState = (cardApp != null) ? cardApp.getState() :
                                                            AppState.APPSTATE_UNKNOWN;
                if (serviceState == ServiceState.STATE_POWER_OFF) {
                    return DisconnectCause.POWER_OFF;
                } else if (serviceState == ServiceState.STATE_OUT_OF_SERVICE
                        || serviceState == ServiceState.STATE_EMERGENCY_ONLY ) {
                    return DisconnectCause.OUT_OF_SERVICE;
                } else {
                    if (isPhoneTypeGsm()) {
                        if (uiccAppState != AppState.APPSTATE_READY) {
                            return DisconnectCause.ICC_ERROR;
                        } else if (causeCode == CallFailCause.ERROR_UNSPECIFIED) {
                            if (phone.mSST.mRestrictedState.isCsRestricted()) {
                                return DisconnectCause.CS_RESTRICTED;
                            } else if (phone.mSST.mRestrictedState.isCsEmergencyRestricted()) {
                                return DisconnectCause.CS_RESTRICTED_EMERGENCY;
                            } else if (phone.mSST.mRestrictedState.isCsNormalRestricted()) {
                                return DisconnectCause.CS_RESTRICTED_NORMAL;
                            } else {
                                return DisconnectCause.ERROR_UNSPECIFIED;
                            }
                        } else if (causeCode == CallFailCause.NORMAL_CLEARING) {
                            return DisconnectCause.NORMAL;
                        } else {
                            // If nothing else matches, report unknown call drop reason
                            // to app, not NORMAL call end.
                            return DisconnectCause.ERROR_UNSPECIFIED;
                        }
                    } else {
                        if (phone.mCdmaSubscriptionSource ==
                                CdmaSubscriptionSourceManager.SUBSCRIPTION_FROM_RUIM
                                && uiccAppState != AppState.APPSTATE_READY) {
                            return DisconnectCause.ICC_ERROR;
                        } else if (causeCode==CallFailCause.NORMAL_CLEARING) {
                            return DisconnectCause.NORMAL;
                        } else {
                            return DisconnectCause.ERROR_UNSPECIFIED;
                        }
                    }
                }
        }
    }

由于causeCode值是NORMAL_CLEARING，所以得到的DisconnectCause值是DisconnectCause.NORMAL

接着调用onDisconnect方法

public boolean onDisconnect(int cause) {
        boolean changed = false;

        mCause = cause;

        if (!mDisconnected) {
            doDisconnect();

            if (DBG) Rlog.d(LOG_TAG, "onDisconnect: cause=" + cause);

            mOwner.getPhone().notifyDisconnect(this);

            if (mParent != null) {
                changed = mParent.connectionDisconnected(this);
            }

            mOrigConnection = null;
        }
        clearPostDialListeners();
        releaseWakeLock();
        return changed;
    }

步骤23之后的流程就跟上篇讲解phone拒接流程一样，这里就不重复描述了

详见http://www.cnblogs.com/lance2016/p/6391096.html

至此，一个电话挂断的流程就分析完了，结合log打印会对整个流程的理解更加深刻