來電亮屏流程分析

本文檔是針對手機來電時候自主點亮屏幕這一流程的分析,非常自然的就將其分為2個階段,第一個是來電，第二個是點亮屏幕。

來電的流程：

來電消息是從RIL層接收到的。然后才開始傳遞上來。

AT??????:?RING?????????????????????????????

AT??????:?AT<?RING????????????????????????????

AT??????:?RIL_URC_READER:RING?????????????????

AT??????:?RIL_URC_READER?Enter?processLine????

use-Rlog/RLOG-RIL:?Nw?URC:RING????????????????

use-Rlog/RLOG-RIL:?receiving?RING!!!!!!???????

use-Rlog/RLOG-RIL:?receiving?first?RING!!!!!!?

use-Rlog/RLOG-RIL:?sending?ECPI!!!!!!??

?同一時候也向RIL.java上報UNSOL_RESPONSE_CALL_STATE_CHANGED消息，RIL.java收到將才標志轉換為RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED，這告訴我們真正處理代碼在哪個分支里，看以下代碼：??

processUnsolicited?(Parcel?p)?{//主動上報的命令??

…省略代碼……??

case?RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED:??

mCallStateRegistrants?.notifyRegistrants(new?AsyncResult(null,?null,?null);

break;?

}

上面這個通知發到GsmCallTracker.java文件里的構造函數中。在這里面就能看到要找的事件（EVENT_CALL_STATE_CHANGE）了：

?GsmCallTracker?(GSMPhone?phone)?{

????this.phone?=?phone;

????cm?=?phone.mCM;

????cm.registerForCallStateChanged(this,?EVENT_CALL_STATE_CHANGE,?null);

????cm.registerForOn(this,?EVENT_RADIO_AVAILABLE,?null);

????cm.registerForNotAvailable(this,?EVENT_RADIO_NOT_AVAILABLE,?null);

}?

在文件BaseCommands.java中有對函數的實現：

public?void?registerForCallStateChanged(Handler?h,?int?what,?Object?obj)?{

????????Registrant?r?=?new?Registrant?(h,?what,?obj);

????????mCallStateRegistrants.add(r);

????}???

當然EVENT_CALL_STATE_CHANGE這個消息的上會有非常多原因。除了來電消息RING，還有掛斷消息NOCARRIER、電話狀態改變消息CLCC等，RIL都會作為EVENT_CALL_STATE_CHANGE報給GsmCallTracker.java，GsmCalTracker.java收到之后會。在handleMessage()相應分支中進行處理。代碼例如以下：

case?EVENT_CALL_STATE_CHANGE:

pollCallsWhenSafe();

break;

進入pollCallsWhenSafe（）方法中，又見消息。這回是主動查詢CLCC，查詢一下通話列表，即查詢全部的通話詳情，在這個分支?EVENT_POLL_CALLS_RESULT里獲得查詢結果：

????protected?void?pollCallsWhenSafe()?{

????????needsPoll?=?true;

????????if?(checkNoOperationsPending())?{

????????????lastRelevantPoll?=?obtainMessage(EVENT_POLL_CALLS_RESULT);

????????????cm.getCurrentCalls(lastRelevantPoll);

????????}

}

處理EVENT_POLL_CALLS_RESULT消息是在GsmCallTracker.java中：

????case?EVENT_POLL_CALLS_RESULT:

????????ar?=?(AsyncResult)msg.obj;

?

????????if?(msg?==?lastRelevantPoll)?{

????????????if?(DBG_POLL)?log(

????????????????????"handle?EVENT_POLL_CALL_RESULT:?set?needsPoll=F");

????????????needsPoll?=?false;

????????????lastRelevantPoll?=?null;

????????????handlePollCalls((AsyncResult)msg.obj);

????????}

break;

進入handlePollCalls()方法中。在這種方法里將揭開CLCC命令返回參數和connections集合里的元素的是什么關系？handlePollCalls()方法中會進行一個for循環操作。底層查的通話列表用DriverCall類表示。FrameWork層則抽象為GsmConnection類。在這里先看一個關于CLCC命令的樣例：

????CLCC?：?1、0、2、0、0???1881234578?…..

????先是CLCC這個command。后面

????第一個參數表示?index序號，

????每二個如是0表示來電、1表示去電，

????第三個是電話狀態。

????第四個表示是數據業務還是語音業務。

????第五個表示是否是視頻會議。后面再跟著號碼。

CLCC返回的電話列表中，第一個參數就是沒路通話的編號，從1開始編號，相同能夠看到GsmCallTracker中保存的GsmConnection的集合connections集合對象是一個數組，數組編號是從0開始的，所以我們會看到會有一個dc.index?==?i+1；的操作。相應關系就是這里建立的。

之后會把底層查的DriverCall對象和GsmCallTracker中保存的GsmConnection對象進行比較。如DriverCall對象為空，我們本地保持的GsmConnection對象存在，非常顯然，是這路電話掛斷了。反之如過DriverCall對象有，GsmConnection對象不存在，則是一個來電：

if?(conn?==?null?&&?dc?!=?null){??

if?(newRinging?!=?null)?{

????? phone.notifyNewRingingConnection(newRinging);

}}

在phoneBase.java里發出通知??

protected?void?notifyNewRingingConnectionP(Connection?cn)?{??

if?(!mIsVoiceCapable)??

return;??

syncResult?ar?=?new?AsyncResult(null,?cn,?null);??

mNewRingingConnectionRegistrants.notifyRegistrants(ar);??

?}

再后面的代碼就離開Framework層了，這里把來電消息通知給上層應用：

private?void?registerForNotifications()?{??

mCM.registerForNewRingingConnection(this,PHONE_NEW_RINGING_CONNECTION,?null);??

?….后面的代碼省略???

?}???

public?void?registerForNewRingingConnection(??

Handler?h,?int?what,?Object?obj)?{??

checkCorrectThread(h);????????

mNewRingingConnectionRegistrants.addUnique(h,?what,?obj);??

}

PHONE_NEW_RINGING_CONNECTION這個消息發送出去之后,是在CallNotifier.java文件里處理的：

public?void?handleMessage(Message?msg)?{

????????if(handleMessageMTK(msg))?{

????????????return;

????????}

????????switch?(msg.what)?{

????????????case?CallStateMonitor.PHONE_NEW_RINGING_CONNECTION:

????????????????log("RINGING...?(new)");

????????????????onNewRingingConnection((AsyncResult)?msg.obj);

????????????????mSilentRingerRequested?=?false;

????????????????break;

}…省略代碼…

}

以下有對來電鈴音連接事件的處理：

/**

*?Handles?a?"new?ringing?connection"?event?from?the?telephony?layer.

*/

private?void?onNewRingingConnection(AsyncResult?r)?{

????????Connection?c?=?(Connection)?r.result;

????????log("onNewRingingConnection():?state?=?"?+?mCM.getState()?+?",?conn?=?{?"?+?c?+?"?}");

????????Call?ringing?=?c.getCall();

????????Phone?phone?=?ringing.getPhone();?

if?(ignoreAllIncomingCalls(phone))?{//在這里面會有去查詢黑名單或則其它操作，從而決定是否自己主動拒接來電

????????????

????????????PhoneUtils.hangupRingingCall(ringing);

????????????return;

????????}??????

…省略代碼…????????

Call.State?state?=?c.getState();//手機狀態

????????//?State?will?be?either?INCOMING?or?WAITING.

????????if?(VDBG)?log("-?connection?is?ringing!??state?=?"?+?state);????????

????????if?(PhoneUtils.isRealIncomingCall(state))?{???????????????????????

PhoneUtils.setAudioControlState(PhoneUtils.AUDIO_RINGING);???????????

????????????if?(mApplication.getWiredHeadsetManager().isHeadsetPlugged()?&&?isIncomingMuteOrVibrate())?{

????????????????playCallWaitingTone();

????????????}???????????

????????????PhoneUtils.setAudioMode();

????????????}?else?{???????????

???????????? mShouldSkipRing?=?true;

???????? }

????????startIncomingCallQuery(c);???????

????????sendEmptyMessageDelayed(DELAY_AUTO_ANSWER,?3000);???????

????????if?(VDBG)?log("-?onNewRingingConnection()?done.");

????}

在這之后會依據獲取當前手機的狀態模式推斷是否處于摘機狀態等。

PhoneConstants.State?state?=?mCM.getState();

推斷響鈴的模式：

public?void?setRingerMode(int?ringerMode)?{…代碼省略…}

startIncomingCallQuery(c)//取數據庫查找相應的資源，比方用什么鈴音就會去里面查找：

private?void?startIncomingCallQuery(Connection?c)?{

if?(shouldStartQuery)?{

setDefaultRingtoneUri(c);//設置默認的鈴聲

}

}

public?void?applyDeviceVolume(int?device)?{…代碼省略…}//設置設備音量

public?Uri?getDefaultRingtone(int?type)?{}//依據傳入的type類型設置默認的鈴音,1為TYPE_RINGTONE，2為TYPE_NOTIFICATION

public?static?CallerInfoToken?startGetCallerInfo(Context?context,?Connection?c,CallerInfoAsyncQuery.OnQueryCompleteListener?listener,?Object?cookie,RawGatewayInfo?info){}//這里面能夠看到呼叫方的號碼，和當前電話用的什么網絡。

startIncomingCallQuery中最后會運行響鈴并通知有來電了：

private?void?ringAndNotifyOfIncomingCall(Connection?c)?{

mCallModeler.onNewRingingConnection(c);

}

函數onNewRingingConnection的實現：

Call?onNewRingingConnection(Connection?conn)?{

????????Log.i(TAG,?"onNewRingingConnection");

????????updateDualTalkCallInfo();

????????final?Call?call?=?getCallFromMap(mCallMap,?conn,?true);

????????if?(call?!=?null)?{

????????????updateCallFromConnection(call,?conn,?false);

????????????for?(int?i?=?0;?i?<?mListeners.size();?++i)?{

????????????????mListeners.get(i).onIncoming(call);

????????????}

????????}

????????PhoneGlobals.getInstance().updateWakeState();//這里開始更新喚醒狀態

????????return?call;

????}

更新喚醒狀態：

void?updateWakeState()?{

…省略代碼…

requestWakeState(keepScreenOn??

?WakeState.FULL?:?WakeState.SLEEP);

}

public?void?requestWakeState(WakeState?ws)?{

????????synchronized?(this)?{

????????????if?(mWakeState?!=?ws)?{

????????????????if(is82SMBPlugged()){

????????????????????ws?=?WakeState.SLEEP;

????????????????}

????????????????switch?(ws)?{

????????????????????case?PARTIAL:

????????????????????????mPartialWakeLock.acquire();

????????????????????????if?(mWakeLock.isHeld())?{

????????????????????????????mWakeLock.release();

????????????????????????}

????????????????????????break;

????????????????????case?FULL:

????????????????????????mWakeLock.acquire();

????????????????????????if?(mPartialWakeLock.isHeld())?{

????????????????????????????mPartialWakeLock.release();

????????????????????????}

????????????????????????break;

????????????????????case?SLEEP:

????????????????????default:

????????????????????????if?(mWakeLock.isHeld())?{

????????????????????????????mWakeLock.release();

????????????????????????}

????????????????????????if?(mPartialWakeLock.isHeld())?{

????????????????????????????mPartialWakeLock.release();

????????????????????????}

????????????????????????break;

????????????????}

????????????????mWakeState?=?ws;

????????????}

????????}

????}

以上就基本上完畢了來電流程的總結。

亮屏的流程：

點亮屏幕是從喚醒開始的:

首先依據mProximityPositive的值檢查屏幕當前是否處于遠離狀態,假設是遠離狀態的話才會去點亮,否則是不會去點亮的。

假設處于遠離狀態須要去推斷喚醒鎖是否須要更新。假設須要更新那么就會去運行更新操作。

函數wakeUpNoUpdateLocked(eventTime)的作用就是去推斷喚醒鎖是否須要更新，首先會依據mWakefulness的值去運行相應的操作，假設為WAKEFULNESS_ASLEEP，且mIPOShutdown為false時候。運行例如以下操作：

case?WAKEFULNESS_ASLEEP://接收到喚醒消息

????if?(!mIPOShutdown)?{

????????sendPendingNotificationsLocked();

????????mNotifier.onWakeUpStarted();//開始喚醒

????????mSendWakeUpFinishedNotificationWhenReady?=?true;

????}

????break;

要開始喚醒就須要捕獲亮屏堵塞個數。每捕獲一次就添加一個。

然后更新廣播鎖,即是運行函數updatePendingBroadcastLocked()。首先也是捕獲堵塞塊，也是捕獲一次就添加一個，然后發送一個MSG_BROADCAST的消息。且這個消息是異步運行的。

接收到MSG_BROADCAST這個消息后會運行sendNextBroadcast()方法。假設powerState的值等于POWER_STATE_AWAKE，那么就發送喚醒廣播。否則就發送休眠廣播。

if?(powerState?==?POWER_STATE_AWAKE)?{

sendWakeUpBroadcast();//發起喚醒廣播

}?else?{

sendGoToSleepBroadcast(goToSleepReason);//發送休眠廣播

}

推斷用戶界面鎖是否更新，依據mUserActivityPending的值決定是否發送異步運行的消息MSG_USER_ACTIVITY，從而運行方法sendUserActivity()。

發送的喚醒廣播最重要的操作就是運行方法：

ActivityManagerNative.getDefault().wakingUp()，這種方法不是馬上就能完畢的。可能會有一定延遲才干完畢。可是當他完畢后，且系統已經準備好就會發出一個喚醒已經結束的廣播：

if?(ActivityManagerNative.isSystemReady())?{

mContext.sendOrderedBroadcastAsUser(mScreenOnIntent,?UserHandle.ALL,?null,mWakeUpBroadcastDone,?mHandler,?0,?null,?null);????????

}?else?{

EventLog.writeEvent(EventLogTags.POWER_SCREEN_BROADCAST_STOP,?2,?1);

????sendNextBroadcast();

}

這個廣播的接收器例如以下：

private?final?BroadcastReceiver?mWakeUpBroadcastDone?=?new?BroadcastReceiver(){????????

@Override

public?void?onReceive(Context?context,?Intent?intent)?{

???? EventLog.writeEvent(EventLogTags.POWER_SCREEN_BROADCAST_DONE,?1,

???????? SystemClock.uptimeMillis()?-?mBroadcastStartTime,?1);

????????????sendNextBroadcast();

????????}

}

這里的廣播從發送到接收到有一定延遲。甚至可能出現有巨大延遲的狀況,由于僅僅有系統覺得亮屏結束的時候才會認定廣播接收完畢。

當確認須要更新喚醒鎖。即是wakeUpNoUpdateLocked(eventTime)的值為true時，就會去運行更新就是運行方法updatePowerStateLocked()。

updatePowerStateLocked(eventTime)這個函數非常重要，他會去更新非常多鎖的狀態代碼例如以下：

private?void?updatePowerStateLocked()?{

if?(!mSystemReady?||?mDirty?==?0)?{

???? return;

????}

updateIsPoweredLocked(mDirty);

updateStayOnLocked(mDirty);

?

final?long?now?=?SystemClock.uptimeMillis();

int?dirtyPhase2?=?0;

for?(;;)?{

????int?dirtyPhase1?=?mDirty;

????dirtyPhase2?|=?dirtyPhase1;

????mDirty?=?0;

????updateWakeLockSummaryLocked(dirtyPhase1);

updateUserActivitySummaryLocked(now,?dirtyPhase1);

????if?(!updateWakefulnessLocked(dirtyPhase1))?{

????????break;

????}

}

?

updateDreamLocked(dirtyPhase2);

updateDisplayPowerStateLocked(dirtyPhase2);

?

if?(mDisplayReady)?{

?????sendPendingNotificationsLocked();

}

updateSuspendBlockerLocked();

}

updateWakeLockSummaryLocked(dirtyPhase1)：更新喚醒鎖主鎖，依據wakeLocked中flag值與上PowerManager.WAKE_LOCK_LEVEL_MASK進行匹配，依據各種匹配結果對mWakeLockSummary進行賦值。這里一共同擁有例如以下幾種鎖：

PARTIAL_WAKE_LOCK:保持CPU?運轉，屏幕和鍵盤燈有可能是關閉的。

SCREEN_DIM_WAKE_LOCK：保持CPU?運轉，同意保持屏幕顯示但有可能是灰的，同意關閉鍵盤燈

SCREEN_BRIGHT_WAKE_LOCK：保持CPU?運轉。同意保持屏幕高亮顯示。同意關閉鍵盤燈

FULL_WAKE_LOCK：保持CPU?運轉，保持屏幕高亮顯示，鍵盤燈也保持亮度

我們這里關注的就是FULL_WAKE_LOCK。當mWakefulness不為WAKEFULNESS_ASLEEP

mWakeLockSummary?|=?WAKE_LOCK_CPU?|?WAKE_LOCK_SCREEN_BRIGHT?|?WAKE_LOCK_BUTTON_BRIGHT。假設此時mWakefulness還等于WAKEFULNESS_AWAKE那么還要或上WAKE_LOCK_STAY_AWAKE。

updateUserActivitySummaryLocked(now,?dirtyPhase1)：這個函數作用就依據不同的情況設置mUserActivitySummary的值，而此時就須要注意給其賦值的三個參數，各自是：按鍵亮：USER_ACTIVITY_BUTTON_BRIGHT。屏幕亮：USER_ACTIVITY_SCREEN_BRIGHT。和屏幕暗：USER_ACTIVITY_SCREEN_DIM。

updateDisplayPowerStateLocked(dirtyPhase2)：這個函數的作用是更新顯示狀態鎖的。這里面最重要的newScreenState屏幕狀態值，screenBrightness屏幕亮度值。

函數中會對按鍵背光亮滅做處理：

if?(?(?(mWakeLockSummary?&?WAKE_LOCK_BUTTON_BRIGHT)?!=?0?)?||

???????(?(mUserActivitySummary?&?USER_ACTIVITY_BUTTON_BRIGHT)?!=?0)?)?{

mButtonLight.setBrightness(screenBrightness);

}?else?{

mButtonLight.turnOff();

}

mDisplayReady顯示是否準備好，他會通過mDisplayPowerController的requestPowerState方法推斷得出，注意這里有延時，或者是說有了反饋消息才干獲得mDisplayReady的值。requestPowerState方法返回的是mDisplayReadyLocked。而僅僅有當change的值為false，即是狀態鎖沒有更新的時候。

在有更改的時候可能會去發送更新電源狀態鎖即是運行函數sendUpdatePowerStateLocked()，而這個函數的作用就是發出一個更新電源狀態的消息：MSG_UPDATE_POWER_STATE。接收消息的地方是：

switch?(msg.what)?{

case?MSG_UPDATE_POWER_STATE:

????updatePowerState();

????break;

}

updatePowerState():更新電源狀態，這個函數非常重要，后文重點說明。

updateSuspendBlockerLocked()：這個函數主要是對mWakeLockSuspendBlocker和mDisplaySuspendBlocker的獲取和釋放進行操作。并對相應的鎖進行設值，獲取設為true。釋放設為false。

updateDreamLocked(dirtyPhase2)：更新休眠鎖，這個函數是對休眠狀態下進行一些處理。當中會發出一個MSG_SANDMAN消息，處理這個消息的是handleSandman()方法。

以下重點介紹下updatePowerState()方法：

private?void?updatePowerState()?{

…省略代碼…

…依據距離傳感器設置亮滅屏和是否激活距離傳感器…

…光感功能…

if?(wantScreenOn(mPowerRequest.screenState))?{//反饋屏幕狀態亮屏?

???? if?(mScreenAutoBrightness?>=?0?&&?mLightSensorEnabled?&&?mPowerRequest.useAutoBrightness)?{????????????????

????????????????target?=?mScreenAutoBrightness;

????????????????slow?=?mUsingScreenAutoBrightness;

????????????????mUsingScreenAutoBrightness?=?true;

????????????}?else?{???????????

????????????????target?=?mPowerRequest.screenBrightness;

????????????????slow?=?false;

????????????????mUsingScreenAutoBrightness?=?false;

????????????}

????????if?(mPowerRequest.screenState?==?DisplayPowerRequest.SCREEN_STATE_DIM)?{//滅屏

????????????????target?=?Math.min(target?-?SCREEN_DIM_MINIMUM_REDUCTION,

????????????????????????mScreenBrightnessDimConfig);

????????????????slow?=?false;???????????????

????????????????if?(FeatureOption.MTK_AAL_SUPPORT)?{

????????????????????nativeSetScreenState(SCREEN_STATE_DIM,?clampScreenBrightness(target));

????????????????}???????????????

????????????}?else?if?(wasDim)?{

????????????????slow?=?false;????????????????

????????????????if?(FeatureOption.MTK_AAL_SUPPORT)?{

????????????????????nativeSetScreenState(SCREEN_STATE_ON,?clampScreenBrightness(target));

????????????????}

????????????}

????????????animateScreenBrightness(clampScreenBrightness(target),

????????????????????slow??

?BRIGHTNESS_RAMP_RATE_SLOW?:?BRIGHTNESS_RAMP_RATE_FAST);//動態決定緩慢改變亮度還是迅速改變

????????}?else?{????????????

????????????mUsingScreenAutoBrightness?=?false;

????????}

??//動態運行屏幕亮或者屏幕滅

??????if?(!mScreenOffBecauseOfProximity?||?mPowerRequest.forceWakeUpEnable)?{

????????????if?(wantScreenOn(mPowerRequest.screenState))?{????????????

????????????????if?(!mElectronBeamOffAnimator.isStarted())?{

????????????????????setScreenOn(true);?//設置屏亮

????????????????????mSbScreenOnIsStart?=?true;

????????????????????if?(mPowerRequest.blockScreenOn//亮屏處于堵塞狀態且電量等級為0，0為滅屏，1為亮屏

????????????????????????????&&?mPowerState.getElectronBeamLevel()?==?0.0f)?{????????????????????

????????????????????????blockScreenOn();//堵塞亮屏

????????????????????????mPowerState.updateElectronBeam();

????????????????????}?else?{

????????????????????????unblockScreenOn();//開啟亮屏

????????????????????????if?(USE_ELECTRON_BEAM_ON_ANIMATION)?{

條件一直為false，里面代碼忽略

????????????????????????}?else?{//設置亮屏

????????????????????????????mPowerState.setElectronBeamLevel(1.0f);????????????????????????????

????????????????????????????mPowerState.dismissElectronBeam();

????????????????????????????mSbScreenOnIsStart?=?false;

????????????????????????}

????????????????????}

????????????????}

????????????}?else?{//滅屏時就會運行這里??????????????

????????????????if?(!mElectronBeamOnAnimator.isStarted())?{

????????????????????if?(!mElectronBeamOffAnimator.isStarted())?{

????????????????????????if?(mPowerState.getElectronBeamLevel()?==?0.0f?||?mShutDownFlag_D)?{

????????????????????????????setScreenOn(false);//設置滅屏

????????????????????????????mShutDownFlag_D?=?false;?

??????????????????????? }?else?if?(mPowerState.prepareElectronBeam(

????????????????????????????????mElectronBeamFadesConfig??

????????????????????????????????????????ElectronBeam.MODE_FADE?:

????????????????????????????????????????????????ElectronBeam.MODE_COOL_DOWN)

????????????????????????????????&&?mPowerState.isScreenOn())?{

????????????????????????????mElectronBeamOffAnimator.start();

????????????????????????}?else?{;

????????????????????????????mElectronBeamOffAnimator.end();

????????????????????????}

????????????????????}

????????????????}

????????????}

????????}

????????if?(mustNotify

????????????????&&?!mScreenOnWasBlocked

????????????????&&?!mElectronBeamOnAnimator.isStarted()

????????????????&&?!mElectronBeamOffAnimator.isStarted()

????????????????&&?mPowerState.waitUntilClean(mCleanListener))?{

????????????synchronized?(mLock)?{//確定顯示是否準備好，亮度是否變化。異步

????????????????if?(!mPendingRequestChangedLocked)?{

????????????????????mDisplayReadyLocked?=?true;

????????????????}

????????????}

????????????sendOnStateChangedWithWakelock();

????????}

????}

setScreenOn(boolean?on)：設置亮屏的方法：

if?(mPowerState.isScreenOn()?!=?on)?{//要處于亮屏狀態

??? ?mPowerState.setScreenOn(on);

??? ?if?(on)?{

?? ?????? mNotifier.onScreenOn();

???? }?else?{

???????? mNotifier.onScreenOff();

???? }??????????

}

public?void?setScreenOn(boolean?on)?{//?mPowerState.setScreenOn(on)

????if?(mScreenOn?!=?on)?{

????????mScreenOn?=?on;

????????mScreenReady?=?false;

????????scheduleScreenUpdate();//使屏幕更新

????}

}

public?void?onScreenOn()?{

????????try?{

????????????mBatteryStats.noteScreenOn();

????????}?catch?(RemoteException?ex)?{

????????}

??? }

scheduleScreenUpdate()終于會去實現接口mScreenUpdateRunnable，會依據是否亮屏mScreenOn?，電子束等級mElectronBeamLevel，屏幕亮度值mScreenBrightness這三個參數設置更新后的屏幕亮度。然后會對方法返回值進行推斷即是：

mPhotonicModulator?.setState(mScreenOn,?brightness)的返回值，它返回的是mChangeInProgress的值，假設為true，則覺得屏幕更新準備好，假設為false。則覺得屏幕更新沒有準備好。在這函數運行中可能去實現一個接口，而接口mTask的實現是：

???private?final?Runnable?mTask?=?new?Runnable()?{

????????????public?void?run()?{????????????????

//申請變更知道完畢

????????????????for?(;;)?{//強制反復運行，直到有條件跳出來

????????????????????final?boolean?on;

????????????????????final?boolean?onChanged;

????????????????????final?int?backlight;

????????????????????final?boolean?backlightChanged;

????????????????????synchronized?(mLock)?{

????????????????????????on?=?mPendingOn;

????????????????????????onChanged?=?(on?!=?mActualOn);

????????????????????????backlight?=?mPendingBacklight;

????????????????????????backlightChanged?=?(backlight?!=?mActualBacklight);

????????????????????????if?(!onChanged?&&?!backlightChanged)?{

????????????????????????????mChangeInProgress?=?false;

????????????????????????????break;

????????????????????????}

????????????????????????mActualOn?=?on;

????????????????????????mActualBacklight?=?backlight;

????????????????????}

????????????????????if?(onChanged?&&?on)?{//有變化且是需點亮狀態

????????????????????????mDisplayBlanker.unblankAllDisplays();//點亮屏幕

????????????????????}

????????????????????if?(mShutDownFlag)?{

????????????????????????try?{

????????????????????????????Thread.sleep(mDelay);??

????????????????????????}?catch?(InterruptedException?e)?{}

????????????????????}

????????????????????if?(backlightChanged)?{//期望亮度值mPendingBacklight和真實亮度值mActualBacklight是否相等，相等時backlightChanged為false，否則為true

????????????????????????mBacklight.setBrightness(backlight);//這里會去底層設置點亮屏。非常重要。backlightChanged才會決定亮不亮屏

????????????????????????mDisplayBlanker.setBlNotify();

????????????????????????if?(on)?{

????????????????????????????Handler?monitorHandler?=?MessageMonitorLogger.getMsgLoggerHandler();

????????????????????????????if?(monitorHandler?!=?null?&&?monitorHandler.hasMessages(MessageMonitorLogger.START_MONITOR_EXECUTION_TIMEOUT_MSG,?monitorHandler))?{????????????????????????????????monitorHandler.removeMessages(MessageMonitorLogger.START_MONITOR_EXECUTION_TIMEOUT_MSG,?monitorHandler);

???????????????????????????????????????????????????????????}

????????????????????????}

????????????????????}

????????????????????if?(onChanged?&&?!on)?{//有變化且是需熄滅狀態

????????????????????????mDisplayBlanker.blankAllDisplays();//熄滅屏幕

????????????????????}

????????????????}

????????????????postScreenUpdateThreadSafe();

????????????}

????};

???public?void?unblankAllDisplays()?{//開啟全顯示，這里有可能會有延時

??? synchronized?(this)?{

????????nativeSetAutoSuspend(false);

????????nativeSetInteractive(true);????????????mDisplayManagerService.unblankAllDisplaysFromPowerManager();

?????????mBlanked?=?false;

?????????mHDMI.hdmiPowerEnable(true);?

?????????mWfdShouldBypass?=?false;

?????????}

???}

unblankAllDisplaysFromPowerManager()：開啟顯示，終于會依據全顯示的狀態值來確定設備開不開啟鎖，代碼例如以下：

switch?(mAllDisplayBlankStateFromPowerManager)?{

????????????????case?DISPLAY_BLANK_STATE_BLANKED:

????????????????????device.blankLocked();

????????????????????break;

????????????????case?DISPLAY_BLANK_STATE_UNBLANKED:

????????????????????device.unblankLocked();

????????????????????break;

????????????}

wakingUp()是在ActivityManagerNative.getDefault().wakingUp()調用時才運行，而要掉這里應該是監聽到了亮屏，監聽器：?mPolicy.screenTurningOn(mScreenOnListener)。

private?final?WindowManagerPolicy.ScreenOnListener?mScreenOnListener?=

????????????new?WindowManagerPolicy.ScreenOnListener()?{

????????@Override

????????public?void?onScreenOn()?{

????????????synchronized?(mLock)?{

????????????????if?(mScreenOnBlockerAcquired?&&?!mPendingWakeUpBroadcast)?{

????????????????????mScreenOnBlockerAcquired?=?false;

????????????????????mScreenOnBlocker.release();

????????????????}

????????????}

????????}

????}//這個非常重要

public?void?wakingUp()?{

???????if?(checkCallingPermission(android.Manifest.permission.DEVICE_POWER)

????????????????!=?PackageManager.PERMISSION_GRANTED)?{

????????????throw?new?SecurityException("Requires?permission?"

????????????????????+?android.Manifest.permission.DEVICE_POWER);

????????}

?

????????synchronized(this)?{

????????????mWentToSleep?=?false;

????????????updateEventDispatchingLocked();

????????????comeOutOfSleepIfNeededLocked();//從休眠狀態退出來

????????}

????}

手機在感受到距離由近及遠的時候也會去點亮屏幕：

private?final?SensorEventListener?mProximitySensorListener?=?new?SensorEventListener()?{//距離傳感器監聽器

????????@Override

????????public?void?onSensorChanged(SensorEvent?event)?{

????????????if?(mProximitySensorEnabled)?{

????????????????final?long?time?=?SystemClock.uptimeMillis();

????????????????final?float?distance?=?event.values[0];

????????????????boolean?positive?=?distance?>=?0.0f?&&?distance?<?mProximityThreshold;

????????????????handleProximitySensorEvent(time,?positive);?//?positive?的值為false，表示離開。為true，表示靠近。

?

????????????}

????????}

????};

?

當mDisplayReady為true時會運行方法sendPendingNotificationsLocked()，這個函數的作用就是發送關于鎖結束的提示，不管是亮屏結束還是熄屏結束都會調用這里，實現的地方例如以下：

if?(mSendWakeUpFinishedNotificationWhenReady)?{//喚醒過程結束

????mSendWakeUpFinishedNotificationWhenReady?=?false;

????mNotifier.onWakeUpFinished();

}

if?(mSendGoToSleepFinishedNotificationWhenReady)?{//休眠過程結束

????mSendGoToSleepFinishedNotificationWhenReady?=?false;

????mNotifier.onGoToSleepFinished();

}

mSendWakeUpFinishedNotificationWhenReady這個值在剛進入喚醒階段就被置為了true的，所以最重要的還是什么時候mDisplayReady的值為true。

真正運行亮屏的是底層驅動去做的,而通知底層驅動的是函數:

public?void?setBrightness(int?brightness)?{//?Task中的

//mBacklight.setBrightness(backlight)

setBrightness(brightness,?BRIGHTNESS_MODE_USER);

}

?

public?void?setBrightness(int?brightness,?int?brightnessMode)?{

synchronized?(this)?{

???? int?color?=?brightness?&?0x000000ff;

???? color?=?0xff000000?|?(color?<<?16)?|?(color?<<?8)?|?color;

????????????????setLightLocked(color,?LIGHT_FLASH_NONE,?0,?0,?brightnessMode);

}

}

protected?void?setLightLocked(int?color,?int?mode,?int?onMS,?int?offMS,?int?brightnessMode)?{

if?(color?!=?mColor?||?mode?!=?mMode?||?onMS?!=?mOnMS?||?offMS?!=?mOffMS)?{

setLight_native(mNativePointer,?mId,?color,?mode,?onMS,?offMS,?brightnessMode);//這個函數就會實現去通知底層驅動更新屏幕亮度

}

}