sendmessage Service的工作过程使用Android O(8.0) A(6)

在H中 case CREATE_SERVICE:

Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, ("serviceCreate: " + String.valueOf(msg.obj)));

handleCreateService((CreateServiceData)msg.obj);

Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

通过handleCreateService来处理，其中CreateServiceData 对象所描述的是一个Ashmem中的Service

    private void handleCreateService(CreateServiceData data) {
        // If we are getting ready to gc after going to the background, well
        // we are back active so skip it.
        unscheduleGcIdler();

        LoadedApk packageInfo = getPackageInfoNoCheck(
                data.info.applicationInfo, data.compatInfo);
        Service service = null;
        try {
            //1.通过类加载器创建Service的实例
            java.lang.ClassLoader cl = packageInfo.getClassLoader();
            service = (Service) cl.loadClass(data.info.name).newInstance();
        } catch (Exception e) {
            if (!mInstrumentation.onException(service, e)) {
                throw new RuntimeException(
                    "Unable to instantiate service " + data.info.name
                    + ": " + e.toString(), e);
            }
        }

        try {
            if (localLOGV) Slog.v(TAG, "Creating service " + data.info.name);

            ContextImpl context = ContextImpl.createAppContext(this, packageInfo);
            context.setOuterContext(service);
            //2.创建Application对象，并调用其onCreate
            Application app = packageInfo.makeApplication(false, mInstrumentation);
            //3.通过Service的attach，和ContextImpl建立联系
            service.attach(context, this, data.info.name, data.token, app,
                    ActivityManager.getService());
            //4.调用 Service的onCreate方法，并将Service放入到mServices中
            service.onCreate();
            mServices.put(data.token, service);
            try {
                ActivityManager.getService().serviceDoneExecuting(
                        data.token, SERVICE_DONE_EXECUTING_ANON, 0, 0);
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
        } catch (Exception e) {
            if (!mInstrumentation.onException(service, e)) {
                throw new RuntimeException(
                    "Unable to create service " + data.info.name
                    + ": " + e.toString(), e);
            }
        }
    }

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