Android 11 -- app 服务保活

app服务保活 (android 11 源码)

frameworks/base/services/core/java/com/android/server/am/ActiveServices.java

stop后台service的逻辑：

AMS的doStopUidLocked方法会先stop 后台service，再去更新uid并分发uid的change
stopInBackgroundLocked回调后，service不一定会真被stop

void stopInBackgroundLocked(int uid) {
        // Stop all services associated with this uid due to it going to the background
        // stopped state.
        // 获取该uid下的所有service
        ServiceMap services = mServiceMap.get(UserHandle.getUserId(uid));
        ArrayList<ServiceRecord> stopping = null;
        if (services != null) {
            for (int i = services.mServicesByInstanceName.size() - 1; i >= 0; i--) {
                ServiceRecord service = services.mServicesByInstanceName.valueAt(i);
                 // start方式启动的service
                if (service.appInfo.uid == uid && service.startRequested) {
                    if (mAm.getAppStartModeLocked(service.appInfo.uid, service.packageName,
                            service.appInfo.targetSdkVersion, -1, false, false, false)
                            != ActivityManager.APP_START_MODE_NORMAL) {
                        if (stopping == null) {
                            stopping = new ArrayList<>();
                        }
                        String compName = service.shortInstanceName;

                        //add  包名过滤防止它被杀
                        if(compName.contains("com.google.wangyiyun"))
                            continue;
                        //end
                        ......
                        
                        // 將当前service添加进stoppping列表
                        stopping.add(service);

                        // If the app is under bg restrictions, also make sure that
                        // any notification is dismissed
                        if (appRestrictedAnyInBackground(
                                service.appInfo.uid, service.packageName)) {
                            cancelForegroundNotificationLocked(service);
                        }
                    }
                }
            }
            if (stopping != null) {
                for (int i=stopping.size()-1; i>=0; i--) {
                    ServiceRecord service = stopping.get(i);
                    service.delayed = false;
                    services.ensureNotStartingBackgroundLocked(service);
                    // stop service
                    stopServiceLocked(service);
                }
            }
        }
    }
    

//这个函数用停止app的服务
private void stopServiceLocked(ServiceRecord service) {
        if (service.delayed) {
            // If service isn't actually running, but is being held in the
            // delayed list, then we need to keep it started but note that it
            // should be stopped once no longer delayed.
            if (DEBUG_DELAYED_STARTS) Slog.v(TAG_SERVICE, "Delaying stop of pending: " + service);
            service.delayedStop = true;
            return;
        }
        StatsLog.write(StatsLog.SERVICE_STATE_CHANGED, service.appInfo.uid,
                service.name.getPackageName(), service.name.getClassName(),
                StatsLog.SERVICE_STATE_CHANGED__STATE__STOP);
        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);
    }
    

bringDownServiceIfNeededLocked（...）
private final void bringDownServiceIfNeededLocked(ServiceRecord r, boolean knowConn,
            boolean hasConn) {

        if (isServiceNeededLocked(r, knowConn, hasConn)) {
            return;
        }
        // 如果有新拉起service的需求，本次不会stop该service
        if (mPendingServices.contains(r)) {
            return;
        }
        bringDownServiceLocked(r);
    }

    

(android-12)app进入后台，关掉杀死serivce
参考一