Android Framework—Service

介绍

Service是一种可以在后台执行长时间运行操作而不提供界面的应用组件。服务可以由其他应用组件启动，而且即使用户切换到其他应用，服务仍将在后台继续运行。此外，组件可以通过绑定到服务与之进行交互，甚至是执行进程之间的通信。

正文

1.Service的介绍

<service android:name=".MyService"android:isolatedProcess="true"android:directBootAware="true"android:process=":subService"/>

import android.app.Service
import android.content.Intent
import android.os.IBinderclass PreloadService : Service() {override fun onBind(p0: Intent?): IBinder? {return null}
}

service的标签属性比较简单，具体可以参考官网。我在这里就举几个属性的例子:

isolatedProcess:服务与系统其余部分隔离的特殊进程下运行。

process:指定服务运行的进程名称。以:开头，系统会根据需要时创建新进程，并且服务会在该进程运行。

directBootAware:服务是否支持直接启动，也就是可以在用户解锁设备之前运行。

Service的生命周期

它的生命周期会和我们使用Service的不同 也有所不同。左边是startService 右边是bindService。我们汇编可以根据源码 再来看看执行的时机。

Service的运行模式

1.前台Service:执行一些用户能注意到的操作，前台服务必须显示通知。

2.后台Service:后台服务不会影响用户，在26以后，系统会对后台服务施加限制。

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2.Service的启动

1.startService

在源码中我们可以直接在Activity中调用startService,那就跟一下 看看它是如何开启Service的。 文件目录:/android/frameworks/base/core/java/android/content/ContextWrapper.java

public ComponentName startServiceAsUser(Intent service, UserHandle user) {return mBase.startServiceAsUser(service, user);
}
//mBase就是ContextImpl 参考Activity创建流程
Context mBase;public ComponentName startService(Intent service) {warnIfCallingFromSystemProcess();return startServiceCommon(service, false, mUser);
}//开启Service
private ComponentName startServiceCommon(Intent service, boolean requireForeground,UserHandle user) {try {//校验intentvalidateServiceIntent(service);//设置intent的属性，准备离开现有进程service.prepareToLeaveProcess(this);//调用AMS的startService  传入了 当前进程，service(目标servcie),true ComponentName cn = ActivityManager.getService().startService(mMainThread.getApplicationThread(), service, service.resolveTypeIfNeeded(getContentResolver()), requireForeground,getOpPackageName(), user.getIdentifier());return cn;} catch (RemoteException e) {throw e.rethrowFromSystemServer();}
}

看看AMS是如何开启Service

public ComponentName startService(IApplicationThread caller, Intent service,String resolvedType, boolean requireForeground, String callingPackage, int userId)throws TransactionTooLargeException {//判断是否是隔离进程调用enforceNotIsolatedCaller("startService");synchronized(this) {//获取pidfinal int callingPid = Binder.getCallingPid();//获取uidfinal int callingUid = Binder.getCallingUid();//获取origidfinal long origId = Binder.clearCallingIdentity();ComponentName res;try {//调用mService的startServiceLocked 这里的mService就是之前讲AMS启动流程时创建的ActiveServices 用来管理Service的res = mServices.startServiceLocked(caller, service,resolvedType, callingPid, callingUid,requireForeground, callingPackage, userId);} finally {Binder.restoreCallingIdentity(origId);}return res;}
}
文件目录:/android/frameworks/base/services/core/java/com/android/server/am/ActiveServices.javaComponentName startServiceLocked(IApplicationThread caller, Intent service, String resolvedType,int callingPid, int callingUid, boolean fgRequired, String callingPackage, final int userId)throws TransactionTooLargeException {return startServiceLocked(caller, service, resolvedType, callingPid, callingUid, fgRequired,callingPackage, userId, false);
}ComponentName startServiceLocked(IApplicationThread caller, Intent service, String resolvedType,int callingPid, int callingUid, boolean fgRequired, String callingPackage,final int userId, boolean allowBackgroundActivityStarts)throws TransactionTooLargeException {final boolean callerFg;if (caller != null) {//不为null 获取到当前进程的ProcessRecordfinal ProcessRecord callerApp = mAm.getRecordForAppLocked(caller);callerFg = callerApp.setSchedGroup != ProcessList.SCHED_GROUP_BACKGROUND;} else {callerFg = true;}//得到ServiceRecord对象:先从mServiceMap中查找 如果有就返回 没有的话就创建（通过pkms.resolveService 查找service创建ServiceRecord包装成ServiceLookupResult返回）ServiceLookupResult res =retrieveServiceLocked(service, null, resolvedType, callingPackage,callingPid, callingUid, userId, true, callerFg, false, false);//拿到ServiceRecord  ServiceRecord继承自BinderServiceRecord r = res.record;final boolean bgLaunch = !mAm.isUidActiveLocked(r.appInfo.uid);boolean forcedStandby = false;if (bgLaunch && appRestrictedAnyInBackground(r.appInfo.uid, r.packageName)) {forcedStandby = true;}boolean forceSilentAbort = false;if (fgRequired) {//这里是false不走 前台走这里}if (forcedStandby || (!r.startRequested && !fgRequired)) {//判断是否运行启动服务：常驻内存、蓝牙、电源白名单允许直接启动服务 否则执行默认策略：如果大于AndroidO不允许启动后台服务final int allowed = mAm.getAppStartModeLocked(r.appInfo.uid, r.packageName,r.appInfo.targetSdkVersion, callingPid, false, false, forcedStandby);if (allowed != ActivityManager.APP_START_MODE_NORMAL) {//不允许启动服务的逻辑if (allowed == ActivityManager.APP_START_MODE_DELAYED || forceSilentAbort) {return null;}if (forcedStandby) {if (fgRequired) {//falsereturn null;}}UidRecord uidRec = mAm.mProcessList.getUidRecordLocked(r.appInfo.uid);return new ComponentName("?", "app is in background uid " + uidRec);}}if (r.appInfo.targetSdkVersion < Build.VERSION_CODES.O && fgRequired) {//不走这里fgRequired = false;}//记录时间戳r.lastActivity = SystemClock.uptimeMillis();//设置已经开启了r.startRequested = true;r.delayedStop = false;r.fgRequired = fgRequired;//添加了一个ServiceRecord.StartItem taskRemoved = false  如果是BindService 不会添加 因为他直接调用的是realStartServicer.pendingStarts.add(new ServiceRecord.StartItem(r, false, r.makeNextStartId(),service, neededGrants, callingUid));if (fgRequired) {//这里不走}final ServiceMap smap = getServiceMapLocked(r.userId);boolean addToStarting = false;if (allowBackgroundActivityStarts) {r.whitelistBgActivityStartsOnServiceStart();}//调用startServiceInnerLockedComponentName cmp = startServiceInnerLocked(smap, service, r, callerFg, addToStarting);return cmp;
}ComponentName startServiceInnerLocked(ServiceMap smap, Intent service, ServiceRecord r,boolean callerFg, boolean addToStarting) throws TransactionTooLargeException {ServiceState stracker = r.getTracker();if (stracker != null) {stracker.setStarted(true, mAm.mProcessStats.getMemFactorLocked(), r.lastActivity);}r.callStart = false;synchronized (r.stats.getBatteryStats()) {r.stats.startRunningLocked();}//调用bringUpServiceLocked 开启进程String error = bringUpServiceLocked(r, service.getFlags(), callerFg, false, false);if (error != null) {return new ComponentName("!!", error);}if (r.startRequested && addToStarting) {boolean first = smap.mStartingBackground.size() == 0;smap.mStartingBackground.add(r);r.startingBgTimeout = SystemClock.uptimeMillis() + mAm.mConstants.BG_START_TIMEOUT;if (DEBUG_DELAYED_SERVICE) {RuntimeException here = new RuntimeException("here");here.fillInStackTrace();} else if (DEBUG_DELAYED_STARTS) {}if (first) {smap.rescheduleDelayedStartsLocked();}} else if (callerFg || r.fgRequired) {smap.ensureNotStartingBackgroundLocked(r);}return r.name;
}private String bringUpServiceLocked(ServiceRecord r, int intentFlags, boolean execInFg,boolean whileRestarting, boolean permissionsReviewRequired)throws TransactionTooLargeException {if (r.app != null && r.app.thread != null) {//已经运行sendServiceArgsLocked(r, execInFg, false);return null;}if (!whileRestarting && mRestartingServices.contains(r)) {return null;}if (mRestartingServices.remove(r)) {clearRestartingIfNeededLocked(r);}if (r.delayed) {getServiceMapLocked(r.userId).mDelayedStartList.remove(r);r.delayed = false;}//是否需要进程隔离下 运行final boolean isolated = (r.serviceInfo.flags&ServiceInfo.FLAG_ISOLATED_PROCESS) != 0;//获取进程名final String procName = r.processName;//创建HostingRecordHostingRecord hostingRecord = new HostingRecord("service", r.instanceName);ProcessRecord app;if (!isolated) {//非隔离进程//获取到service的ProcessRecordapp = mAm.getProcessRecordLocked(procName, r.appInfo.uid, false);if (app != null && app.thread != null) {//进程已经存在 启动了try {app.addPackage(r.appInfo.packageName, r.appInfo.longVersionCode, mAm.mProcessStats);realStartServiceLocked(r, app, execInFg);return null;} catch (TransactionTooLargeException e) {throw e;} catch (RemoteException e) {}}} else {//隔离进程//第一次开启isolatedProc是nullapp = r.isolatedProc;if (WebViewZygote.isMultiprocessEnabled()&& r.serviceInfo.packageName.equals(WebViewZygote.getPackageName())) {hostingRecord = HostingRecord.byWebviewZygote(r.instanceName);}if ((r.serviceInfo.flags & ServiceInfo.FLAG_USE_APP_ZYGOTE) != 0) {hostingRecord = HostingRecord.byAppZygote(r.instanceName, r.definingPackageName,r.definingUid);}}//服务还没启动调用startProcessLocked 创建进程if (app == null && !permissionsReviewRequired) {if ((app=mAm.startProcessLocked(procName, r.appInfo, true, intentFlags,hostingRecord, false, isolated, false)) == null) {String msg = "Unable to launch app "+ r.appInfo.packageName + "/"+ r.appInfo.uid + " for service "+ r.intent.getIntent() + ": process is bad"; bringDownServiceLocked(r);return msg;}if (isolated) {r.isolatedProc = app;}}if (r.fgRequired) {//不走这里 是falsemAm.tempWhitelistUidLocked(r.appInfo.uid,SERVICE_START_FOREGROUND_TIMEOUT, "fg-service-launch");}if (!mPendingServices.contains(r)) {//假如mPendingServices中mPendingServices.add(r);}if (r.delayedStop) {r.delayedStop = false;if (r.startRequested) {stopServiceLocked(r);}}return null;
}

在AMS这里会先检查Service是否可以执行(常驻内存、蓝牙、电源白名单允许直接启动服务)，接着调用bringUpServiceLocked 判断是否需要隔离进程如果非隔离 就看是否已经启动进程 执行realStartServiceLocked，否则是隔离进程 直接开启新进程。我们没有设置隔离进程 所以我们会直接开启新进程，开启进程的过程在之前已经接触很多次了，我们直接跳过，开启成功之后会将ServiceRecord添加到mPendingServices中去。所以我们看看进程创建成功之后会如何开启Service。

private boolean attachApplicationLocked(@NonNull IApplicationThread thread,int pid, int callingUid, long startSeq) {//到这里来thread.bindApplication(processName, appInfo, providers,instr2.mClass,profilerInfo, instr2.mArguments,instr2.mWatcher,instr2.mUiAutomationConnection, testMode,mBinderTransactionTrackingEnabled, enableTrackAllocation,isRestrictedBackupMode || !normalMode, app.isPersistent(),new Configuration(app.getWindowProcessController().getConfiguration()),app.compat, getCommonServicesLocked(app.isolated),mCoreSettingsObserver.getCoreSettingsLocked(),buildSerial, autofillOptions, contentCaptureOptions);boolean badApp = false;boolean didSomething = false;//在这里开启activityif (normalMode) {try {didSomething = mAtmInternal.attachApplication(app.getWindowProcessController());} catch (Exception e) {badApp = true;}}if (!badApp) {try {//开启ServicedidSomething |= mServices.attachApplicationLocked(app, processName);} catch (Exception e) {badApp = true;}}return true;
}
//还是在ActiveService中boolean attachApplicationLocked(ProcessRecord proc, String processName)throws RemoteException {boolean didSomething = false;//此时Services的size是大于0的if (mPendingServices.size() > 0) {ServiceRecord sr = null;try {for (int i=0; i<mPendingServices.size(); i++) {sr = mPendingServices.get(i);if (proc != sr.isolatedProc && (proc.uid != sr.appInfo.uid|| !processName.equals(sr.processName))) {continue;}mPendingServices.remove(i);i--;proc.addPackage(sr.appInfo.packageName, sr.appInfo.longVersionCode,mAm.mProcessStats);//调用realStartServiceLocked开启servicerealStartServiceLocked(sr, proc, sr.createdFromFg);didSomething = true;if (!isServiceNeededLocked(sr, false, false)) {bringDownServiceLocked(sr);}}} catch (RemoteException e) {throw e;}}return didSomething;
}//开启service
private final void realStartServiceLocked(ServiceRecord r,ProcessRecord app, boolean execInFg) throws RemoteException {//服务和当前进程绑定r.setProcess(app);r.restartTime = r.lastActivity = SystemClock.uptimeMillis();//添加到ProcessRecord中final boolean newService = app.services.add(r);//埋炸弹scheduleServiceTimeoutLockedbumpServiceExecutingLocked(r, execInFg, "create");//更新进程LRUmAm.updateLruProcessLocked(app, false, null);updateServiceForegroundLocked(r.app, /* oomAdj= */ false);//更新OOMAdjmAm.updateOomAdjLocked(OomAdjuster.OOM_ADJ_REASON_START_SERVICE);boolean created = false;try {synchronized (r.stats.getBatteryStats()) {r.stats.startLaunchedLocked();}mAm.notifyPackageUse(r.serviceInfo.packageName,PackageManager.NOTIFY_PACKAGE_USE_SERVICE);app.forceProcessStateUpTo(ActivityManager.PROCESS_STATE_SERVICE);//调用到应用进程 也就是服务进程 ActivityThreadapp.thread.scheduleCreateService(r, r.serviceInfo,mAm.compatibilityInfoForPackage(r.serviceInfo.applicationInfo),app.getReportedProcState());r.postNotification();created = true;} catch (DeadObjectException e) {} finally {}if (r.whitelistManager) {app.whitelistManager = true;}//处理Bind我们不处理 没有Bind 此时直说startServicerequestServiceBindingsLocked(r, execInFg);updateServiceClientActivitiesLocked(app, null, true);if (newService && created) {app.addBoundClientUidsOfNewService(r);}if (r.startRequested && r.callStart && r.pendingStarts.size() == 0) {r.pendingStarts.add(new ServiceRecord.StartItem(r, false, r.makeNextStartId(),null, null, 0));}//发送Service的argssendServiceArgsLocked(r, execInFg, true);if (r.delayed) {getServiceMapLocked(r.userId).mDelayedStartList.remove(r);r.delayed = false;}
}回到ActivityThread看看它的scheduleCreateServicepublic final void scheduleCreateService(IBinder token,ServiceInfo info, CompatibilityInfo compatInfo, int processState) {updateProcessState(processState, false);CreateServiceData s = new CreateServiceData();s.token = token;s.info = info;s.compatInfo = compatInfo;//给mH发送了H.CREATE_SERVICEsendMessage(H.CREATE_SERVICE, s);
}case CREATE_SERVICE:handleCreateService((CreateServiceData)msg.obj);break;
//创建Service
private void handleCreateService(CreateServiceData data) {unscheduleGcIdler();LoadedApk packageInfo = getPackageInfoNoCheck(data.info.applicationInfo, data.compatInfo);Service service = null;try {//反射创建Servicejava.lang.ClassLoader cl = packageInfo.getClassLoader();service = packageInfo.getAppFactory().instantiateService(cl, data.info.name, data.intent);} catch (Exception e) {}try {//创建ContextContextImpl context = ContextImpl.createAppContext(this, packageInfo);context.setOuterContext(service);//调用makeApplicationApplication app = packageInfo.makeApplication(false, mInstrumentation);//调用service的attach 绑定ActivityThread token Application 以及AMSservice.attach(context, this, data.info.name, data.token, app,ActivityManager.getService());//调用service的onCreateservice.onCreate();//存入到mService中去mServices.put(data.token, service);try {//告诉AMS创建完成ActivityManager.getService().serviceDoneExecuting(data.token, SERVICE_DONE_EXECUTING_ANON, 0, 0);} catch (RemoteException e) {throw e.rethrowFromSystemServer();}} catch (Exception e) {}
}public final void attach(Context context,ActivityThread thread, String className, IBinder token,Application application, Object activityManager) {attachBaseContext(context);mThread = thread;           // NOTE:  unused - remove?mClassName = className;mToken = token;mApplication = application;mActivityManager = (IActivityManager)activityManager;mStartCompatibility = getApplicationInfo().targetSdkVersion< Build.VERSION_CODES.ECLAIR;
}到AMS 处理服务创建public void serviceDoneExecuting(IBinder token, int type, int startId, int res) {synchronized(this) {if (!(token instanceof ServiceRecord)) {throw new IllegalArgumentException("Invalid service token");}mServices.serviceDoneExecutingLocked((ServiceRecord)token, type, startId, res);}
}//AMS开启Service成功
void serviceDoneExecutingLocked(ServiceRecord r, int type, int startId, int res) {boolean inDestroying = mDestroyingServices.contains(r);if (r != null) {//在这里把炸弹拆除serviceDoneExecutingLocked(r, inDestroying, inDestroying);} 
}
发送的args
private final void sendServiceArgsLocked(ServiceRecord r, boolean execInFg,boolean oomAdjusted) throws TransactionTooLargeException {final int N = r.pendingStarts.size();if (N == 0) {//不是0return;}ArrayList<ServiceStartArgs> args = new ArrayList<>();while (r.pendingStarts.size() > 0) {ServiceRecord.StartItem si = r.pendingStarts.remove(0);if (si.intent == null && N > 1) {continue;}si.deliveredTime = SystemClock.uptimeMillis();r.deliveredStarts.add(si);si.deliveryCount++;//埋炸弹bumpServiceExecutingLocked(r, execInFg, "start");if (!oomAdjusted) {oomAdjusted = true;mAm.updateOomAdjLocked(r.app, true, OomAdjuster.OOM_ADJ_REASON_START_SERVICE);}if (r.fgRequired && !r.fgWaiting) {//前台Serviceif (!r.isForeground) {scheduleServiceForegroundTransitionTimeoutLocked(r);} else {r.fgRequired = false;}}int flags = 0;if (si.deliveryCount > 1) {flags |= Service.START_FLAG_RETRY;}if (si.doneExecutingCount > 0) {flags |= Service.START_FLAG_REDELIVERY;}args.add(new ServiceStartArgs(si.taskRemoved, si.id, flags, si.intent));}//执行ActivityThread的scheduleServiceArgsr.app.thread.scheduleServiceArgs(r, slice);
}public final void scheduleServiceArgs(IBinder token, ParceledListSlice args) {List<ServiceStartArgs> list = args.getList();for (int i = 0; i < list.size(); i++) {ServiceStartArgs ssa = list.get(i);ServiceArgsData s = new ServiceArgsData();s.token = token;s.taskRemoved = ssa.taskRemoved;s.startId = ssa.startId;s.flags = ssa.flags;s.args = ssa.args;//给mH发送SERVICE_ARGSsendMessage(H.SERVICE_ARGS, s);}
}case SERVICE_ARGS:handleServiceArgs((ServiceArgsData)msg.obj);break;//处理Args
private void handleServiceArgs(ServiceArgsData data) {Service s = mServices.get(data.token);if (s != null) {try {if (data.args != null) {data.args.setExtrasClassLoader(s.getClassLoader());data.args.prepareToEnterProcess();}int res;if (!data.taskRemoved) {//这里是false 所以会执行onStartCommandres = s.onStartCommand(data.args, data.flags, data.startId);} else {}QueuedWork.waitToFinish();try {//通知AMS 拆除炸弹ActivityManager.getService().serviceDoneExecuting(data.token, SERVICE_DONE_EXECUTING_START, data.startId, res);} catch (RemoteException e) {}} catch (Exception e) {}}
}

进程创建之后，会调用AMS的attachApplication 接着处理service(ActiveService)，之前创建之后会添加到mPendingServices中，现在继续处理调用realStartServiceLocked来开启Service，在开启的过程中会埋入一个炸弹(给Handler发送一个SERVICE_TIMEOUT_MSG) 如果超时未处理会弹出ANR，然后调用app.thread.scheduleCreateService通知客户端创建反射Service、Context 调用onCreate 把Service存入到mService中，调用AMS的serviceDoneExecuting进行炸弹的拆除。 然后再埋炸弹 调用app.thread.scheduleServiceArgs 调用service.onStartCommand再通知AMS 拆除炸弹。 这样Service就运行起来了。我们再看看Service的onStop。

还是回到ContextImpl

public boolean stopService(Intent service) {return stopServiceCommon(service, mUser);
}private boolean stopServiceCommon(Intent service, UserHandle user) {validateServiceIntent(service);service.prepareToLeaveProcess(this);//调用AMS的stopServiceint res = ActivityManager.getService().stopService(mMainThread.getApplicationThread(), service,service.resolveTypeIfNeeded(getContentResolver()), user.getIdentifier());return res != 0;
}public int stopService(IApplicationThread caller, Intent service,String resolvedType, int userId) {enforceNotIsolatedCaller("stopService");synchronized(this) {//调用ActiveService的stopServiceLockedreturn mServices.stopServiceLocked(caller, service, resolvedType, userId);}
}int stopServiceLocked(IApplicationThread caller, Intent service,String resolvedType, int userId) {//获取到调用这的ProcessRecordfinal ProcessRecord callerApp = mAm.getRecordForAppLocked(caller);//获取ServiceRecord ServiceLookupResult r = retrieveServiceLocked(service, null, resolvedType, null,Binder.getCallingPid(), Binder.getCallingUid(), userId, false, false, false, false);if (r != null) {if (r.record != null) {final long origId = Binder.clearCallingIdentity();try {//调用stopServiceLockedstopServiceLocked(r.record);} finally {Binder.restoreCallingIdentity(origId);}return 1;}return -1;}return 0;
}private void stopServiceLocked(ServiceRecord service) {if (service.delayed) {service.delayedStop = true;return;}synchronized (service.stats.getBatteryStats()) {service.stats.stopRunningLocked();}service.startRequested = false;if (service.tracker != null) {service.tracker.setStarted(false, mAm.mProcessStats.getMemFactorLocked(),SystemClock.uptimeMillis());}service.callStart = false;bringDownServiceIfNeededLocked(service, false, false);
}private final void bringDownServiceIfNeededLocked(ServiceRecord r, boolean knowConn,boolean hasConn) {if (isServiceNeededLocked(r, knowConn, hasConn)) {return;}if (mPendingServices.contains(r)) {return;}bringDownServiceLocked(r);
}private final void bringDownServiceLocked(ServiceRecord r) {if (r.app != null && r.app.thread != null) {boolean needOomAdj = false;//执行unBindfor (int i = r.bindings.size() - 1; i >= 0; i--) {IntentBindRecord ibr = r.bindings.valueAt(i);if (ibr.hasBound) {try {bumpServiceExecutingLocked(r, false, "bring down unbind");needOomAdj = true;ibr.hasBound = false;ibr.requested = false;r.app.thread.scheduleUnbindService(r,ibr.intent.getIntent());} catch (Exception e) {serviceProcessGoneLocked(r);}}}if (needOomAdj) {mAm.updateOomAdjLocked(r.app, true,OomAdjuster.OOM_ADJ_REASON_UNBIND_SERVICE);}}r.fgRequired = false;r.fgWaiting = false;ServiceState stracker = r.getTracker();if (stracker != null) {stracker.setForeground(false, mAm.mProcessStats.getMemFactorLocked(),r.lastActivity);}mAm.mAppOpsService.finishOperation(AppOpsManager.getToken(mAm.mAppOpsService),AppOpsManager.OP_START_FOREGROUND, r.appInfo.uid, r.packageName);mAm.mHandler.removeMessages(ActivityManagerService.SERVICE_FOREGROUND_TIMEOUT_MSG, r);if (r.app != null) {Message msg = mAm.mHandler.obtainMessage(ActivityManagerService.SERVICE_FOREGROUND_CRASH_MSG);msg.obj = r.app;msg.getData().putCharSequence(ActivityManagerService.SERVICE_RECORD_KEY, r.toString());mAm.mHandler.sendMessage(msg);}}
//记录销毁时间r.destroyTime = SystemClock.uptimeMillis();final ServiceMap smap = getServiceMapLocked(r.userId);//从map中移除ServiceRecord found = smap.mServicesByInstanceName.remove(r.instanceName);//移除smap.mServicesByIntent.remove(r.intent);r.totalRestartCount = 0;r.isForeground = false;r.foregroundId = 0;r.foregroundNoti = null;r.clearDeliveredStartsLocked();r.pendingStarts.clear();smap.mDelayedStartList.remove(r);if (r.app != null) {synchronized (r.stats.getBatteryStats()) {r.stats.stopLaunchedLocked();}r.app.services.remove(r);r.app.updateBoundClientUids();if (r.whitelistManager) {updateWhitelistManagerLocked(r.app);}if (r.app.thread != null) {updateServiceForegroundLocked(r.app, false);try {//埋炸弹bumpServiceExecutingLocked(r, false, "destroy");mDestroyingServices.add(r);r.destroying = true;mAm.updateOomAdjLocked(r.app, true,OomAdjuster.OOM_ADJ_REASON_UNBIND_SERVICE);//到客户端执行scheduleStopServicer.app.thread.scheduleStopService(r);} catch (Exception e) {serviceProcessGoneLocked(r);}} else {}} if (r.bindings.size() > 0) {//清空bindingsr.bindings.clear();}if (r.restarter instanceof ServiceRestarter) {((ServiceRestarter)r.restarter).setService(null);}int memFactor = mAm.mProcessStats.getMemFactorLocked();long now = SystemClock.uptimeMillis();if (r.tracker != null) {r.tracker.setStarted(false, memFactor, now);r.tracker.setBound(false, memFactor, now);if (r.executeNesting == 0) {r.tracker.clearCurrentOwner(r, false);r.tracker = null;}}smap.ensureNotStartingBackgroundLocked(r);
}public final void scheduleStopService(IBinder token) {sendMessage(H.STOP_SERVICE, token);
}case STOP_SERVICE:handleStopService((IBinder)msg.obj);schedulePurgeIdler();//清空待清理的资源break;private void handleStopService(IBinder token) {
//从mService中移除掉 只是从map中移除掉了引用,所以我们需要注意Service内部的thread 以及变量不要引起内存泄漏或者线程没有停止Service s = mServices.remove(token);if (s != null) {try {//调用s的onDestorys.onDestroy();s.detachAndCleanUp();Context context = s.getBaseContext();if (context instanceof ContextImpl) {final String who = s.getClassName();((ContextImpl) context).scheduleFinalCleanup(who, "Service");}QueuedWork.waitToFinish();try {//调用AMS的serviceDoneExecuting 拆除炸弹ActivityManager.getService().serviceDoneExecuting(token, SERVICE_DONE_EXECUTING_STOP, 0, 0);} catch (RemoteException e) {throw e.rethrowFromSystemServer();}} catch (Exception e) {}} else {}
}

stop的流程和start的流程差不多，需要注意的是stop只是从map中移除了，我们需要自己释放资源。