Android 挂断电话流程

今天试图解决android挂断电话没有响应的一个bug，跟踪了一下Android 挂断电话流程，在此做个记录

有电话打入是RIL会通知CallNotifier，CallNotifier会调用InCallScreen,这些不再我们今天讨论的范围内，简单提一下。

CallNotifier会调用InCallScreen 代码

 PhoneUtils.showIncomingCallUi(mPhone);

然后InCallScreen会显示InCallTouchUI ,InCallTouchUI 就是可以拖动接听和挂断的那个界面 ，这个页面持有一个SlidingTab控件，这个就是可以左右拖动的控件了。

InCallTouchUI实现了SlidingTab.OnTriggerListener， 在该监听者的OnTrigge方法里面处理接听和挂断的动作，代码如下

    //
    // SlidingTab.OnTriggerListener implementation
    //

    /**
     * Handles "Answer" and "Reject" actions for an incoming call.
     * We get this callback from the SlidingTab
     * when the user triggers an action.
     *
     * To answer or reject the incoming call, we call
     * InCallScreen.handleOnscreenButtonClick() and pass one of the
     * special "virtual button" IDs:
     *   - R.id.answerButton to answer the call
     * or
     *   - R.id.rejectButton to reject the call.
     */
    public void onTrigger(View v, int whichHandle) {
        log("onDialTrigger(whichHandle = " + whichHandle + ")...");

        switch (whichHandle) {
            case SlidingTab.OnTriggerListener.LEFT_HANDLE:
                if (DBG) log("LEFT_HANDLE: answer!");

                hideIncomingCallWidget();

                // ...and also prevent it from reappearing right away.
                // (This covers up a slow response from the radio; see updateState().)
                mLastIncomingCallActionTime = SystemClock.uptimeMillis();

                // Do the appropriate action.
                if (mInCallScreen != null) {
                    // Send this to the InCallScreen as a virtual "button click" event:
                    mInCallScreen.handleOnscreenButtonClick(R.id.answerButton);
                } else {
                    Log.e(LOG_TAG, "answer trigger: mInCallScreen is null");
                }
                break;

            case SlidingTab.OnTriggerListener.RIGHT_HANDLE:
                if (DBG) log("RIGHT_HANDLE: reject!");

                hideIncomingCallWidget();

                // ...and also prevent it from reappearing right away.
                // (This covers up a slow response from the radio; see updateState().)
                mLastIncomingCallActionTime = SystemClock.uptimeMillis();

                // Do the appropriate action.
                if (mInCallScreen != null) {
                    // Send this to the InCallScreen as a virtual "button click" event:
                    mInCallScreen.handleOnscreenButtonClick(R.id.rejectButton);   //看到了吧，这个就是挂断电话的代码了，继续往下看
                } else {
                    Log.e(LOG_TAG, "reject trigger: mInCallScreen is null");
                }
                break;

            default:
                Log.e(LOG_TAG, "onDialTrigger: unexpected whichHandle value: " + whichHandle);
                break;
        }

        // Regardless of what action the user did, be sure to clear out
        // the hint text we were displaying while the user was dragging.
        mInCallScreen.updateSlidingTabHint(0, 0);
    }

InCallScreen的 handleOnscreenButtonClick方法

    /**
     * Handles button clicks from the InCallTouchUi widget.
     */
    /* package */ void handleOnscreenButtonClick(int id) {
        if (DBG) log("handleOnscreenButtonClick(id " + id + ")...");

        switch (id) {
            // TODO: since every button here corresponds to a menu item that we
            // already handle in onClick(), maybe merge the guts of these two
            // methods into a separate helper that takes an ID (of either a menu
            // item *or* touch button) and does the appropriate user action.

            // Actions while an incoming call is ringing:
            case R.id.answerButton:
                internalAnswerCall();
                break;
            case R.id.rejectButton:
                internalHangupRingingCall();             //挂断电话的方法
                break;

            // The other regular (single-tap) buttons used while in-call:
            case R.id.holdButton:
                onHoldClick();
                break;
            case R.id.swapButton:
                internalSwapCalls();
                break;
            case R.id.endButton:
                internalHangup();
                break;
            case R.id.dialpadButton:
                onShowHideDialpad();
                break;
            case R.id.bluetoothButton:
                onBluetoothClick();
                break;
            case R.id.muteButton:
                onMuteClick();
                break;
            case R.id.speakerButton:
                onSpeakerClick();
                break;
            case R.id.addButton:
                PhoneUtils.startNewCall(mCM);  // Fires off an ACTION_DIAL intent
                break;
            case R.id.mergeButton:
            case R.id.cdmaMergeButton:
                PhoneUtils.mergeCalls(mCM);
                break;
            case R.id.manageConferencePhotoButton:
                // Show the Manage Conference panel.
                setInCallScreenMode(InCallScreenMode.MANAGE_CONFERENCE);
                break;

            default:
                Log.w(LOG_TAG, "handleOnscreenButtonClick: unexpected ID " + id);
                break;
        }

        // Just in case the user clicked a "stateful" menu item (i.e. one
        // of the toggle buttons), we force the in-call buttons to update,
        // to make sure the user sees the *new* current state.
        //
        // (But note that some toggle buttons may *not* immediately change
        // the state of the Phone, in which case the updateInCallTouchUi()
        // call here won't have any visible effect.  Instead, those
        // buttons will get updated by the updateScreen() call that gets
        // triggered when the onPhoneStateChanged() event comes in.)
        //
        // TODO: updateInCallTouchUi() is overkill here; it would be
        // more efficient to update *only* the affected button(s).
        // Consider adding API for that.  (This is lo-pri since
        // updateInCallTouchUi() is pretty cheap already...)
        updateInCallTouchUi();
    }

然后调用PhoneUtils.hangupRingingCall(mCM.getFirstActiveRingingCall()); 方法

    /**
     * Hang up the ringing call (aka "Don't answer").
     */
    /* package */ void internalHangupRingingCall() {
        if (DBG) log("internalHangupRingingCall()...");
        if (VDBG) PhoneUtils.dumpCallManager();
        // In the rare case when multiple calls are ringing, the UI policy
        // it to always act on the first ringing call.v
        PhoneUtils.hangupRingingCall(mCM.getFirstActiveRingingCall());
    }

    static boolean hangupRingingCall(Call ringing) {
        if (DBG) log("hangup ringing call");
        int phoneType = ringing.getPhone().getPhoneType();

        if (phoneType == Phone.PHONE_TYPE_CDMA) {
            // CDMA: Ringing call and Call waiting hangup is handled differently.
            // For Call waiting we DO NOT call the conventional hangup(call) function
            // as in CDMA we just want to hungup the Call waiting connection.
            Call.State state = ringing.getState();
            if (state == Call.State.INCOMING) {
                if (DBG) log("hangup ringing call");
                return hangup(ringing);
            } else if (state == Call.State.WAITING) {
                if (DBG) log("hangup Call waiting call");
                final CallNotifier notifier = PhoneApp.getInstance().notifier;
                notifier.sendCdmaCallWaitingReject();
                return true;
            } else {
                // This should never happen cause hangupRingingCall should always be called
                // if the call.isRinging() returns TRUE, which basically means that the call
                // should either be in INCOMING or WAITING state
                if (DBG) log("No Ringing call to hangup");
                return false;
            }
        } else if ((phoneType == Phone.PHONE_TYPE_GSM)
                || (phoneType == Phone.PHONE_TYPE_SIP)) {
            // GSM:  Ringing Call and Call waiting, both are hungup by calling
            // hangup(call) function.
            if (DBG) log("hangup ringing call");
            return hangup(ringing);               
        } else {
            throw new IllegalStateException("Unexpected phone type: " + phoneType);
        }
    }

    /**
     * Trivial wrapper around Call.hangup(), except that we return a
     * boolean success code rather than throwing CallStateException on
     * failure.
     *
     * @return true if the call was successfully hung up, or false
     *         if the call wasn't actually active.
     */
    static boolean hangup(Call call) {
        try {
            call.hangup();
            return true;
        } catch (CallStateException ex) {
            Log.e(LOG_TAG, "Call hangup: caught " + ex, ex);
        }

        return false;
    }

然后进入 GsmCall

    public void
    hangup() throws CallStateException {
        owner.hangup(this);
    }

然后进入frameworks/base/telephony/java/com/android/internal/telephony/gsm/GsmCallTracker.java

可以看到很多不同情况下挂断电话的处理，我们只看第一种情况hangupWaitingOrBackground

    //***** Called from GsmCall

    /* package */ void
    hangup (GsmCall call) throws CallStateException {
        if (call.getConnections().size() == 0) {
            throw new CallStateException("no connections in call");
        }

        if (call == ringingCall) {
            if (Phone.DEBUG_PHONE) log("(ringing) hangup waiting or background");
            cm.hangupWaitingOrBackground(obtainCompleteMessage());
        } else if (call == foregroundCall) {
            if (call.isDialingOrAlerting()) {
                if (Phone.DEBUG_PHONE) {
                    log("(foregnd) hangup dialing or alerting...");
                }
                hangup((GsmConnection)(call.getConnections().get(0)));
            } else {
                hangupForegroundResumeBackground();
            }
        } else if (call == backgroundCall) {
            if (ringingCall.isRinging()) {
                if (Phone.DEBUG_PHONE) {
                    log("hangup all conns in background call");
                }
                hangupAllConnections(call);
            } else {
                hangupWaitingOrBackground();
            }
        } else {
            throw new RuntimeException ("GsmCall " + call +
                    "does not belong to GsmCallTracker " + this);
        }

        call.onHangupLocal();
        phone.notifyPreciseCallStateChanged();
    }

下面进入RIL java， 向rild 发请求了

    public void
    hangupWaitingOrBackground (Message result) {
        RILRequest rr = RILRequest.obtain(RIL_REQUEST_HANGUP_WAITING_OR_BACKGROUND,
                                        result);

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

        send(rr);
    }

再往下就是 rild ， 厂商refence ril工作了 ，其实就是发AT命令，这部分每个厂商可能有自己的实现，就不细说了 。

总之，android的挂断电话流程还是挺复杂的，中间要处理很多不同的情景。