ActivityManagerService

源码－SystemServer.java:1794

    private void startOtherServices() {
         [...]
         mActivityManagerService.setWindowManager(wm);
         [...]

 // We now tell the activity manager it is okay to run third party
        // code.  It will call back into us once it has gotten to the state
        // where third party code can really run (but before it has actually
        // started launching the initial applications), for us to complete our
        // initialization.
        mActivityManagerService.systemReady(() -> {
            Slog.i(TAG, "Making services ready");
            [...]
            startSystemUi(context, windowManagerF);
            [...]
         }, BOOT_TIMEINGS_TRACE_LOG);

             

源码－ActivityManagerService.java:15017

    public void systemReady(final Runnable goingCallback, TimingsTraceLog traceLog) {
           [...]
            sTheRealBuildSerial = IDeviceIdentifiersPolicyService.Stub.asInterface(
                    ServiceManager.getService(Context.DEVICE_IDENTIFIERS_SERVICE))
                    .getSerial();
           [...]
// Start up initial activity.
            mBooting = true;
            // Enable home activity for system user, so that the system can always boot. We don't
            // do this when the system user is not setup since the setup wizard should be the one
            // to handle home activity in this case.
            if (UserManager.isSplitSystemUser() &&
                    Settings.Secure.getInt(mContext.getContentResolver(),
                         Settings.Secure.USER_SETUP_COMPLETE, 0) != 0) {
                ComponentName cName = new ComponentName(mContext, SystemUserHomeActivity.class);
                try {
                    AppGlobals.getPackageManager().setComponentEnabledSetting(cName,
                            PackageManager.COMPONENT_ENABLED_STATE_ENABLED, 0,
                            UserHandle.USER_SYSTEM);
                } catch (RemoteException e) {
                    throw e.rethrowAsRuntimeException();
                }
            }
            startHomeActivityLocked(currentUserId, "systemReady");
   }

当AMS准备好后，就会启动HomeActivity，即Launcher。

The ActivityManagerService is now started and ready for usage. It will run until the system will be shutdown.

@Override
    public boolean shutdown(int timeout) {
        if (checkCallingPermission(android.Manifest.permission.SHUTDOWN)
                != PackageManager.PERMISSION_GRANTED) {
            throw new SecurityException("Requires permission "
                    + android.Manifest.permission.SHUTDOWN);
        }
        boolean timedout = false;
        synchronized(this) {
            mShuttingDown = true;
            mStackSupervisor.prepareForShutdownLocked();
            updateEventDispatchingLocked();
            timedout = mStackSupervisor.shutdownLocked(timeout);
        }
        mAppOpsService.shutdown();
        if (mUsageStatsService != null) {
            mUsageStatsService.prepareShutdown();
        }
        mBatteryStatsService.shutdown();
        synchronized (this) {
            mProcessStats.shutdownLocked();
            notifyTaskPersisterLocked(null, true);
        }
        return timedout;
    }