背景

最近在调研Android P中 AMS，WMS，通讯逻辑，记录整理一下。

SystemServer 文件目录

AOSP\frameworks\base\services\java\com\android\server\SystemServer.java
AOSP\frameworks\base\services\core\java\com\android\server\SystemServiceManager.java
主要是这个两个文件
SystemServer.java 负责创建SystemServiceManager对象，为zygote提供入库，获取和设置系统属性
SystemServiceManager 负责管理一下服务

  // Start services.
        try {
            traceBeginAndSlog("StartServices");
            startBootstrapServices();
            startCoreServices();
            startOtherServices();
            SystemServerInitThreadPool.shutdown();
        } catch (Throwable ex) {
            Slog.e("System", "******************************************");
            Slog.e("System", "************ Failure starting system services", ex);
            throw ex;
        } finally {
            traceEnd();
        }

这个服务也是比较简单注释很全面，从代码启动顺序列一下服务类名：

一、startBootstrapServices

服务列表：

• Installer
• DeviceIdentifiersPolicyService
• ActivityManagerService
• PowerManagerService
• RecoverySystemService
• LightsService
• SidekickService[可选]
• DisplayManagerService
• mSystemServiceManager.startBootPhase(SystemService.PHASE_WAIT_FOR_DEFAULT_DISPLAY);
  //PHASE_WAIT_FOR_DEFAULT_DISPLAY = 100
• PackageManagerService
• OtaDexoptService
• UserManagerService
• OverlayManagerService
• SensorService
  

二、startCoreServices

服务列表：

• BatteryService
• UsageStatsService
• WebViewUpdateService[可选]
• BinderCallsStatsService

三、startOtherServices

服务列表：

• KeyAttestationApplicationIdProviderService
• KeyChainSystemService
• SchedulingPolicyService
• TelecomLoaderService
• TelephonyRegistry
• AccountManagerService
• ContentService
• DropBoxManagerService
• VibratorService [可选]
• ConsumerIrService [可选]
• AlarmManagerService
• Watchdog
• InputManagerService
• WindowManagerService
• START_HIDL_SERVICES
• VrManagerService [可选]
• BluetoothService [可选]
• IpConnectivityMetrics
• NetworkWatchlistService
• PinnerService
  // Bring up services needed for UI.
• InputMethodManagerService
• AccessibilityManagerService
• StorageManagerService
• StorageStatsService
• UiModeManagerService
• LockSettingsService
  在往下就是FactoryTest off、FACTORY_TEST_HIGH_LEVEL需要启动的服务
  不列了，有需要的自行查询
  下面是重点

		traceBeginAndSlog("StartInputManagerService");
		inputManager = new InputManagerService(context);
		traceEnd();

       traceBeginAndSlog("StartWindowManagerService");
       // WMS needs sensor service ready
       ConcurrentUtils.waitForFutureNoInterrupt(mSensorServiceStart, START_SENSOR_SERVICE);
       mSensorServiceStart = null;
       wm = WindowManagerService.main(context, inputManager,
               mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
               !mFirstBoot, mOnlyCore, new PhoneWindowManager());
       ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
               DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
       ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
               /* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
       traceEnd();

       traceBeginAndSlog("SetWindowManagerService");
       mActivityManagerService.setWindowManager(wm);
       traceEnd();

       traceBeginAndSlog("WindowManagerServiceOnInitReady");
       wm.onInitReady();
       traceEnd();