做网站的属于什么工作类型,英雄联盟最新赛事,知名网站用的技术,做网站和软件哪个挣钱前言 本章主要讲解下 什么是 AMS#xff0c;以及它是如何启动的#xff1b;
SystemServer SystemServer 通过按下电源键接通电源之后就会启动 BootRoom#xff0c;BootRoom 就会拉起一个 BootLoader 程序#xff0c;此程序会拉起 Linux Kernel「系统内核」#xff0c;我们…前言 本章主要讲解下 什么是 AMS以及它是如何启动的
SystemServer SystemServer 通过按下电源键接通电源之后就会启动 BootRoomBootRoom 就会拉起一个 BootLoader 程序此程序会拉起 Linux Kernel「系统内核」我们的 Android 系统就会初始化一个用户态进程也就是 init 进程init 进程会执行 initZygote.rc 创建 zygote 进程zygote 进程会 fork「孵化」出 SystemServer「系统服务进程这是 zygote 进程的最大的一个儿子Android 上层需要的所有服务例如 AMSWMSPMSPKMS 等等都会在 SystemServer 初始化起来」 SystemServer 进程就会拉起我们的第一个应用程序「也就是桌面程序 Launcher 进程」 这是一个 Android GUI 关系图
AMS 是什么 从 java 角度来看AMS 就是一个 java 对象实现了 Ibinder 接口所以它是一个用于进程之间通信的接口这个对象初始化是在 SystemServer.java 的 run() 方法里面
ActivityManagerService 从名字就可以看出它是一个服务用来管理 Activity而且是一个系统服务就是包管理服务电池管理服务震动管理服务等
AMS 实现了 Ibinder 接口所以它是一个 Binder这意味着他不但可以用于进程间通信还是一个线程因为一个 Binder 就是一个线程
总得来说ActivityManagerService 是 Android 系统中一个特别重要的系统服务也是我们上层 APP 打交道最多的系统服务之一。ActivityManagerService以下简称AMS 主要负责四大组件的启动、切换、调度以及应用进程的管理和调度工作。所有的 APP 应用都需要与 AMS 打交道 ActivityManager 的组成主要分为以下几个部分
1.服务代理由 ActivityManagerProxy 实现用于与 Server 端提供的系统服务进行进程间通信
2.服务中枢ActivityManagerNative 继承自 Binder 并实现 IActivityManager它提供了服务接口和Binder 接口的相互转化功能并在内部存储服务代理对象并提供了 getDefault 方法返回服务代理
3.Client由 ActivityManager 封装一部分服务接口供 Client 调用。ActivityManager 内部通过调用ActivityManagerNative 的 getDefault 方法可以得到一个 ActivityManagerProxy 对象的引用进而通过该代理对象调用远程服务的方法
4.Server由 ActivityManagerService 实现提供 Server 端的系统服务
AMS 启动流程 SystemServer 创建之后就会调研 run 方法这个 run 方法就会启动 AMS
createSystemContext
创建进程启动launcher把界面显示出来会需要大量的资源例如「文字图片」想要获取这些资源都需要context而系统的资源获取 也需要一个 context 对象所以创建一个系统级别的 context 来获取资源系统资源的加载都是在这个时候被加载的。例如「android/xxx等都属于系统资源」;
private void createSystemContext() {ActivityThread activityThread ActivityThread.systemMain();mSystemContext activityThread.getSystemContext();mSystemContext.setTheme(DEFAULT_SYSTEM_THEME);final Context systemUiContext activityThread.getSystemUiContext();systemUiContext.setTheme(DEFAULT_SYSTEM_THEME);
}这里重点关注的时候 ActivityThread.systemMain() 方法我们进入这个方法看下
public static ActivityThread systemMain() {ThreadedRenderer.initForSystemProcess();ActivityThread thread new ActivityThread();thread.attach(true, 0);return thread;
}这里创建了 ActivityThread 已经进行了 attach 操作
ActivityThread() {mResourcesManager ResourcesManager.getInstance();
}获取资源管理实例
private void attach(boolean system, long startSeq) {if (!system) {// 省略部分代码} else {try {mInstrumentation new Instrumentation();mInstrumentation.basicInit(this);ContextImpl context ContextImpl.createAppContext(this, getSystemContext().mPackageInfo);mInitialApplication context.mPackageInfo.makeApplication(true, null);mInitialApplication.onCreate();} catch (Exception e) {throw new RuntimeException(Unable to instantiate Application(): e.toString(), e);}}// 省略部分代码
}这里做了三件事情
new Instrumentation(); 创建 Instrumentation;ContextImpl.createAppContext(this, getSystemContext().mPackageInfo) 根据 LoadApk 对象创建 Context;context.mPackageInfo.makeApplication(true, null); 初始化 Application;
getSystemContext 其中 createAppContext 需要获取 SystemContext 作为入参我们进入这个方法看下
public ContextImpl getSystemContext() {synchronized (this) {if (mSystemContext null) {mSystemContext ContextImpl.createSystemContext(this);}return mSystemContext;}
}我们进入这个 createSystemContext 看下
static ContextImpl createSystemContext(ActivityThread mainThread) {LoadedApk packageInfo new LoadedApk(mainThread);ContextImpl context new ContextImpl(null, mainThread, packageInfo,ContextParams.EMPTY, null, null, null, null, null, 0, null, null);context.setResources(packageInfo.getResources());context.mResources.updateConfiguration(context.mResourcesManager.getConfiguration(),context.mResourcesManager.getDisplayMetrics());context.mContextType CONTEXT_TYPE_SYSTEM_OR_SYSTEM_UI;return context;
}这个方法做了两件事情
创建 LoadedApk 对象通过 LoadeApk 获取每一个安装在手机上的 APK 信息;创建ContextImpl首次执行getSystemContext会执行createSystemContext创建LoadedApk和contextImpl对象利用刚创建的LoadedApk创建contextImpl;
createAppContext
ContextImpl context new ContextImpl(null, mainThread, packageInfo, null, null, null, 0,null);
context.setResources(packageInfo.getResources());startBootstrapService
启动一系列相关引导服务我们进入源码看下
private void startBootstrapServices(NonNull TimingsTraceAndSlog t) {// 省略部分代码// 启动 APK 安装服务Installer installer mSystemServiceManager.startService(Installer.class);// 省略部分代码// 启动 AMS 服务ActivityTaskManagerService atm mSystemServiceManager.startService(ActivityTaskManagerService.Lifecycle.class).getService();mActivityManagerService ActivityManagerService.Lifecycle.startService(mSystemServiceManager, atm);// 设置 SystemServiceManager mActivityManagerService.setSystemServiceManager(mSystemServiceManager);// 设置 APK 安装器mActivityManagerService.setInstaller(installer);// 初始化 AMS 相关的PMS mActivityManagerService.initPowerManagement();// 设置 SystemServermActivityManagerService.setSystemProcess();
}startCoreServices();
启动核心服务我们进入这个源码看下
private void startCoreServices(NonNull TimingsTraceAndSlog t) {mSystemServiceManager.startService(SystemConfigService.class);mSystemServiceManager.startService(BatteryService.class);mSystemServiceManager.startService(UsageStatsService.class);// 启动用户统计服务mActivityManagerService.setUsageStatsManager(LocalServices.getService(UsageStatsManagerInternal.class));if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_WEBVIEW)) {mWebViewUpdateService mSystemServiceManager.startService(WebViewUpdateService.class);}mSystemServiceManager.startService(CachedDeviceStateService.class);mSystemServiceManager.startService(BinderCallsStatsService.LifeCycle.class);mSystemServiceManager.startService(LooperStatsService.Lifecycle.class);mSystemServiceManager.startService(ROLLBACK_MANAGER_SERVICE_CLASS);mSystemServiceManager.startService(NativeTombstoneManagerService.class);mSystemServiceManager.startService(BugreportManagerService.class);mSystemServiceManager.startService(GpuService.class);
}startOtherServices()
启动其他服务我们进入这个方法看下
private void startOtherServices(NonNull TimingsTraceAndSlog t) {// 省略部分代码// 安装系统的 providermActivityManagerService.installSystemProviders();// 设置 windowManagerwm WindowManagerService.main(context, inputManager,mFactoryTestMode ! FactoryTest.FACTORY_TEST_LOW_LEVEL,!mFirstBoot, mOnlyCore, new PhoneWindowManager());ServiceManager.addService(Context.WINDOW_SERVICE, wm);mActivityManagerService.setWindowManager(wm);// 设置 inputManagerinputManager new InputManagerService(context);ServiceManager.addService(Context.INPUT_SERVICE, inputManager);// 通知mSystemServiceManager.startService(NotificationManagerService.class);mActivityManagerService.systemReady();
}AMS 服务启动流程 这里额外插一句service_manager 和 SystemServiceManager 的区别service_manager 是 C/C 层的用来管理 binder 服务的大管家而 SystemServiceManager 是用来管理各种服务的启动每启动一个服务都会收集到一个 mServices 的集合中
mActivityManagerService ActivityManagerService.Lifecycle.startService(mSystemServiceManager, atm);这里并不是直接 new 出来 AMS而是通过 LifeCycle 这个代理类来创建 AMS而 LifeCycle 的创建是通过反射来实现的LifeCycle 在初始化的时候会初始化 AMS我们进入这个 LifeCycle 看下
public static final class Lifecycle extends SystemService {public Lifecycle(Context context) {super(context);mService new ActivityManagerService(context, sAtm);}public static ActivityManagerService startService(SystemServiceManager ssm, ActivityTaskManagerService atm) {sAtm atm;return ssm.startService(ActivityManagerService.Lifecycle.class).getService();}Overridepublic void onBootPhase(int phase) {mService.mBootPhase phase;if (phase PHASE_SYSTEM_SERVICES_READY) {mService.mBatteryStatsService.systemServicesReady();mService.mServices.systemServicesReady();} else if (phase PHASE_ACTIVITY_MANAGER_READY) {mService.startBroadcastObservers();} else if (phase PHASE_THIRD_PARTY_APPS_CAN_START) {mService.mPackageWatchdog.onPackagesReady();}}// 返回 AMSpublic ActivityManagerService getService() {return mService;}
}LifeCycle 继承 SystemService这个 com.android.server.SystemService 中包含了系统服务启动的各个阶段;
public abstract class SystemService {/** hide */protected static final boolean DEBUG_USER false;/*** The earliest boot phase the system send to system services on boot.*/public static final int PHASE_WAIT_FOR_DEFAULT_DISPLAY 100;/*** Boot phase that blocks on SensorService availability. The service gets started* asynchronously since it may take awhile to actually finish initializing.** hide*/public static final int PHASE_WAIT_FOR_SENSOR_SERVICE 200;/*** After receiving this boot phase, services can obtain lock settings data.*/public static final int PHASE_LOCK_SETTINGS_READY 480;/*** After receiving this boot phase, services can safely call into core system services* such as the PowerManager or PackageManager.*/public static final int PHASE_SYSTEM_SERVICES_READY 500;/*** After receiving this boot phase, services can safely call into device specific services.*/public static final int PHASE_DEVICE_SPECIFIC_SERVICES_READY 520;/*** After receiving this boot phase, services can broadcast Intents.*/public static final int PHASE_ACTIVITY_MANAGER_READY 550;/*** After receiving this boot phase, services can start/bind to third party apps.* Apps will be able to make Binder calls into services at this point.*/public static final int PHASE_THIRD_PARTY_APPS_CAN_START 600;/*** After receiving this boot phase, services can allow user interaction with the device.* This phase occurs when boot has completed and the home application has started.* System services may prefer to listen to this phase rather than registering a* broadcast receiver for {link android.content.Intent#ACTION_LOCKED_BOOT_COMPLETED}* to reduce overall latency.*/// 代表着 服务 启动完成public static final int PHASE_BOOT_COMPLETED 1000;
}我们接着拐回去看 LifeCycle 的 startService 方法这个方法直接调用 SystemServiceManager 的 startService 方法我们进入这个方法看下
public T extends SystemService T startService(ClassT serviceClass) {try {if (!SystemService.class.isAssignableFrom(serviceClass)) {throw new RuntimeException(Failed to create name : service must extend SystemService.class.getName());}final T service;try {// 使用反射创建 LifeCycle 对象ConstructorT constructor serviceClass.getConstructor(Context.class);service constructor.newInstance(mContext);} catch (InstantiationException ex) {throw new RuntimeException(Failed to create service name : service could not be instantiated, ex);} catch (IllegalAccessException ex) {throw new RuntimeException(Failed to create service name : service must have a public constructor with a Context argument, ex);} catch (NoSuchMethodException ex) {throw new RuntimeException(Failed to create service name : service must have a public constructor with a Context argument, ex);} catch (InvocationTargetException ex) {throw new RuntimeException(Failed to create service name : service constructor threw an exception, ex);}startService(service);return service;} finally {Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);}
}这里使用反射的方式来创建 LifeCycle 对象当创建的就会调用其构造方法构造方法中就会创建 AMS然后通过 getService 返回
这个 LifeCycle 中创建的 mService 就是正儿八经的 ActivityManagerService也就是我们需要的 AMS这样做就会让 AMS 有一个生命周期
SystemService 有各个阶段的状态分发最终通过 LifeCycle 重写的 onBootPhase 分发具体逻辑当分发PHASE_SYSTEM_SERVICES_READY 的时候会执行 AMS 中的 ActiveServices 的 systemServiceReady 方法这个 ActiveServices 就是用来管理四大组件的就是说 AMS 通过操作 ActiveServices 来间接管理四大组件
到此 AMS 就创建了出来了接下来看下它在创建的时候都做了哪些事情我们进入 AMS 的构造方法看下
public ActivityManagerService(Context systemContext, ActivityTaskManagerService atm) {LockGuard.installLock(this, LockGuard.INDEX_ACTIVITY);mInjector new Injector(systemContext);mContext systemContext;mFactoryTest FactoryTest.getMode();// 1. 创建 Android UI 线程mSystemThread ActivityThread.currentActivityThread();mUiContext mSystemThread.getSystemUiContext();mHandlerThread new ServiceThread(TAG,THREAD_PRIORITY_FOREGROUND, false /*allowIo*/);mHandlerThread.start();mHandler new MainHandler(mHandlerThread.getLooper());mUiHandler mInjector.getUiHandler(this);mProcStartHandlerThread new ServiceThread(TAG :procStart,THREAD_PRIORITY_FOREGROUND, false /* allowIo */);mProcStartHandlerThread.start();mProcStartHandler new Handler(mProcStartHandlerThread.getLooper());mConstants new ActivityManagerConstants(mContext, this, mHandler);final ActiveUids activeUids new ActiveUids(this, true /* postChangesToAtm */);mPlatformCompat (PlatformCompat) ServiceManager.getService(Context.PLATFORM_COMPAT_SERVICE);mProcessList mInjector.getProcessList(this);mProcessList.init(this, activeUids, mPlatformCompat);mAppProfiler new AppProfiler(this, BackgroundThread.getHandler().getLooper(),new LowMemDetector(this));mPhantomProcessList new PhantomProcessList(this);mOomAdjuster new OomAdjuster(this, mProcessList, activeUids);final BroadcastConstants foreConstants new BroadcastConstants(Settings.Global.BROADCAST_FG_CONSTANTS);foreConstants.TIMEOUT BROADCAST_FG_TIMEOUT;final BroadcastConstants backConstants new BroadcastConstants(Settings.Global.BROADCAST_BG_CONSTANTS);backConstants.TIMEOUT BROADCAST_BG_TIMEOUT;final BroadcastConstants offloadConstants new BroadcastConstants(Settings.Global.BROADCAST_OFFLOAD_CONSTANTS);offloadConstants.TIMEOUT BROADCAST_BG_TIMEOUT;offloadConstants.SLOW_TIME Integer.MAX_VALUE;mEnableOffloadQueue SystemProperties.getBoolean(persist.device_config.activity_manager_native_boot.offload_queue_enabled, false);mFgBroadcastQueue new BroadcastQueue(this, mHandler,foreground, foreConstants, false);mBgBroadcastQueue new BroadcastQueue(this, mHandler,background, backConstants, true);mOffloadBroadcastQueue new BroadcastQueue(this, mHandler,offload, offloadConstants, true);mBroadcastQueues[0] mFgBroadcastQueue;mBroadcastQueues[1] mBgBroadcastQueue;mBroadcastQueues[2] mOffloadBroadcastQueue;// 2. 创建 ActiveServices 用来管理四大组件mServices new ActiveServices(this);mCpHelper new ContentProviderHelper(this, true);mPackageWatchdog PackageWatchdog.getInstance(mUiContext);mAppErrors new AppErrors(mUiContext, this, mPackageWatchdog);mUidObserverController new UidObserverController(mUiHandler);final File systemDir SystemServiceManager.ensureSystemDir();// 电量统计相关服务mBatteryStatsService new BatteryStatsService(systemContext, systemDir,BackgroundThread.get().getHandler());mBatteryStatsService.getActiveStatistics().readLocked();mBatteryStatsService.scheduleWriteToDisk();mOnBattery DEBUG_POWER ? true: mBatteryStatsService.getActiveStatistics().getIsOnBattery();mBatteryStatsService.getActiveStatistics().setCallback(this);mOomAdjProfiler.batteryPowerChanged(mOnBattery);// 进程统计相关服务mProcessStats new ProcessStatsService(this, new File(systemDir, procstats));mAppOpsService mInjector.getAppOpsService(new File(systemDir, appops.xml), mHandler);mUgmInternal LocalServices.getService(UriGrantsManagerInternal.class);mUserController new UserController(this);mPendingIntentController new PendingIntentController(mHandlerThread.getLooper(), mUserController, mConstants);mUseFifoUiScheduling SystemProperties.getInt(sys.use_fifo_ui, 0) ! 0;mTrackingAssociations 1.equals(SystemProperties.get(debug.track-associations));mIntentFirewall new IntentFirewall(new IntentFirewallInterface(), mHandler);mActivityTaskManager atm;// 创建 recentTasks、ActivityStartControllermActivityTaskManager.initialize(mIntentFirewall, mPendingIntentController,DisplayThread.get().getLooper());mAtmInternal LocalServices.getService(ActivityTaskManagerInternal.class);mHiddenApiBlacklist new HiddenApiSettings(mHandler, mContext);Watchdog.getInstance().addMonitor(this);Watchdog.getInstance().addThread(mHandler);updateOomAdjLocked(OomAdjuster.OOM_ADJ_REASON_NONE);try {Process.setThreadGroupAndCpuset(BackgroundThread.get().getThreadId(),Process.THREAD_GROUP_SYSTEM);Process.setThreadGroupAndCpuset(mOomAdjuster.mCachedAppOptimizer.mCachedAppOptimizerThread.getThreadId(),Process.THREAD_GROUP_SYSTEM);} catch (Exception e) {Slog.w(TAG, Setting background thread cpuset failed);}mInternal new LocalService();mPendingStartActivityUids new PendingStartActivityUids(mContext);mTraceErrorLogger new TraceErrorLogger();
}AMS的创建做了五个比较重要的事情
创建 Android UI 线程mSystemThread ActivityThread.currentActivityThread();创建 ActiveServicemServices new ActiveServices(this);创建管理 Activity 的 ActivityStackSupervisor 对象mStackSupervisor new ActivityStackSupervisor(this, mHandler.getLooper());创建最近任务列表mRecentTasks new RecentTasks(this, mStackSupervisor);创建 App的 Activity 生命周期管理类mLifeCycleManager n ew ClientLifeCycleManager();
初始之后我们来看下 start 逻辑
private void start() {// AMS 启动的时候会把所有的应用进程移除掉removeAllProcessGroups();// 启动电池统计服务mBatteryStatsService.publish();mAppOpsService.publish();LocalServices.addService(ActivityManagerInternal.class, mInternal);LocalManagerRegistry.addManager(ActivityManagerLocal.class,(ActivityManagerLocal) mInternal);mActivityTaskManager.onActivityManagerInternalAdded();mPendingIntentController.onActivityManagerInternalAdded();mAppProfiler.onActivityManagerInternalAdded();
}整个的 start 大致过程就结束了
初始化 AMS 相关的 PMS
AMS 在 start 之后会调用 mActivityManagerService.initPowerManagement(); 来初始化 PowerManagerService 服务我们来看下这里面都做了什么
public void initPowerManagement() {mActivityTaskManager.onInitPowerManagement();mBatteryStatsService.initPowerManagement();mLocalPowerManager LocalServices.getService(PowerManagerInternal.class);
}逻辑还是比较简单的初始化 PMS 相关服务
设置 SystemServer
AMS 在 start 之后会调用 mActivityManagerService.setSystemProcess(); 来设置 SystemServer
public void setSystemProcess() {try {ServiceManager.addService(Context.ACTIVITY_SERVICE, this, /* allowIsolated */ true,DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PRIORITY_NORMAL | DUMP_FLAG_PROTO);ServiceManager.addService(ProcessStats.SERVICE_NAME, mProcessStats);ServiceManager.addService(meminfo, new MemBinder(this), /* allowIsolated */ false,DUMP_FLAG_PRIORITY_HIGH);ServiceManager.addService(gfxinfo, new GraphicsBinder(this));ServiceManager.addService(dbinfo, new DbBinder(this));mAppProfiler.setCpuInfoService();ServiceManager.addService(permission, new PermissionController(this));ServiceManager.addService(processinfo, new ProcessInfoService(this));ServiceManager.addService(cacheinfo, new CacheBinder(this));ApplicationInfo info mContext.getPackageManager().getApplicationInfo(android, STOCK_PM_FLAGS | MATCH_SYSTEM_ONLY);mSystemThread.installSystemApplicationInfo(info, getClass().getClassLoader());synchronized (this) {ProcessRecord app mProcessList.newProcessRecordLocked(info, info.processName,false,0,new HostingRecord(system));app.setPersistent(true);app.setPid(MY_PID);app.mState.setMaxAdj(ProcessList.SYSTEM_ADJ);app.makeActive(mSystemThread.getApplicationThread(), mProcessStats);addPidLocked(app);updateLruProcessLocked(app, false, null);updateOomAdjLocked(OomAdjuster.OOM_ADJ_REASON_NONE);}} catch (PackageManager.NameNotFoundException e) {throw new RuntimeException(Unable to find android system package, e);}// Start watching app ops after we and the package manager are up and running.mAppOpsService.startWatchingMode(AppOpsManager.OP_RUN_IN_BACKGROUND, null,new IAppOpsCallback.Stub() {Override public void opChanged(int op, int uid, String packageName) {if (op AppOpsManager.OP_RUN_IN_BACKGROUND packageName ! null) {if (getAppOpsManager().checkOpNoThrow(op, uid, packageName)! AppOpsManager.MODE_ALLOWED) {runInBackgroundDisabled(uid);}}}});final int[] cameraOp {AppOpsManager.OP_CAMERA};mAppOpsService.startWatchingActive(cameraOp, new IAppOpsActiveCallback.Stub() {Overridepublic void opActiveChanged(int op, int uid, String packageName, String attributionTag,boolean active, AttributionFlags int attributionFlags,int attributionChainId) {cameraActiveChanged(uid, active);}});
}这里主要关注三点
第一个是添加各种服务
activity AMSServiceManager.addService(Context.ACTIVITY_SERVICE, this, true);procstats 进程统计ServiceManager.addService(ProcessStats.SERVICE_NAME, mProcessStats);meminfo 内存ServiceManager.addService(“meminfo”, new MemBinder(this));gfxinfo 图像信息ServiceManager.addService(“gfxinfo”, new GraphicsBinder(this));dbinfo 数据库ServiceManager.addService(“dbinfo”, new DbBinder(this));cpuinfo CPUServiceManager.addService(“cpuinfo”, new CpuBinder(this));permission 权限ServiceManager.addService(“permission”, new PermissionController(this));processinfo 进程服务ServiceManager.addService(“processinfo”, new ProcessInfoService(this));usagestats 应用的使用情况
adb shell dumpsys 的各种服务的来源就是从这里添加进去的
第二个是创建用于性能统计的Profiler对象
ApplicationInfo info mContext.getPackageManager().getApplicationInfo( “android”, STOCK_PM_FLAGS | MATCH_SYSTEM_ONLY);mSystemThread.installSystemApplicationInfo(info, getClass().getClassLoader());
第三个是创建ProcessRecord对象
ProcessRecord app newProcessRecordLocked(info, info.processName, false, 0);
安装系统的 provider
在 startOtherService 方法中会调用 mActivityManagerService.installSystemProviders(); 来安装系统的 provider
设置 WindowManager
在 startOtherService 方法中会调用 mActivityManagerService.setWindowManager(wm); 设置窗口管理器
public void setWindowManager(WindowManagerService wm) {synchronized (this) {mWindowManager wm;mWmInternal LocalServices.getService(WindowManagerInternal.class);mActivityTaskManager.setWindowManager(wm);}
}设置windowManager
wm WindowManagerService.main(context, inputManager,mFactoryTestMode ! FactoryTest.FACTORY_TEST_LOW_LEVEL,!mFirstBoot, mOnlyCore, new PhoneWindowManager());ServiceManager.addService(Context.WINDOW_SERVICE, wm);
mActivityManagerService.setWindowManager(wm); setWindowManager 中创建核心 Settings Observer用于监控 Settings「系统设置」
mCoreSettingsObserver new CoreSettingsObserver(this);服务启动完成
当执行到 mActivityManagerService.systemReady 的时候表示前面创建的80多个服务都已经启动完成了 接下来需要启动系统UI、执行一系列服务的systemReady、启动 Luancher
startSystemUi(context, windowManagerF); 启动 systemui 服务
private static void startSystemUi(Context context, WindowManagerService windowManager) {PackageManagerInternal pm LocalServices.getService(PackageManagerInternal.class);Intent intent new Intent();intent.setComponent(pm.getSystemUiServiceComponent());intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);//Slog.d(TAG, Starting service: intent);context.startServiceAsUser(intent, UserHandle.SYSTEM);windowManager.onSystemUiStarted();
}mSystemServiceManager.startBootPhase(SystemService.PHASE_ACTIVITY_MANAGER_READY); 调用AMS服务的ready - service.onBootPhase();
public void startBootPhase(NonNull TimingsTraceAndSlog t, int phase) {mCurrentPhase phase;try {final int serviceLen mServices.size();for (int i 0; i serviceLen; i) {final SystemService service mServices.get(i);long time SystemClock.elapsedRealtime();try {service.onBootPhase(mCurrentPhase);} catch (Exception ex) {}warnIfTooLong(SystemClock.elapsedRealtime() - time, service, onBootPhase);}} finally {}if (phase SystemService.PHASE_BOOT_COMPLETED) {final long totalBootTime SystemClock.uptimeMillis() - mRuntimeStartUptime;SystemServerInitThreadPool.shutdown();}
}startHomeActivityLocked(currentUserId, “systemReady”); 启动Launcher Android开机过程结束就可以看到桌面使用手机;
到这里AMS 的启动流程就结束了
下一章预告 Activity 启动流程
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