android T 前台Service

获取android 13

用户控制: 用户在长时间运行的应用程序上获得更多透明度和控制权：

前台服务仍然需要包含通知，并且应用程序必须请求权限才能显示通知。

FGS 通知现在可以被用户关闭而不影响 FGS

用户可以在任务管理器中查看长时间运行的应用列表
任务管理器还允许用户停止应用程序

通知权限

介绍

权限定义

android T 之前的通知：默认允许通知推送，需要用户跳转至多级设置页面去设置通知权限。
android T新增前台服务的通知权限（运行时权限）：

使用

权限使用

android 13及以上: 应用自行控制权限对话框显示时间
android 12L 及以下: 通常应用启动时弹框

豁免：与媒体会话有关的通知不受此行为变更的影响。

代码

在ServiceRecord的构造方法中会回调updateFgsHasNotificationPermission方法，去异步（避免死锁）从NMS中去获取此app是否有权限发送通知；ServiceRecord仅记录，具体权限校验在NMS中。

// ServiceRecord.java
// Whether FGS package has permissions to show notifications.
boolean mFgsHasNotificationPermission;private void updateFgsHasNotificationPermission() {// Do asynchronous communication with notification manager to avoid deadlocks.final String localPackageName = packageName;final int appUid = appInfo.uid;ams.mHandler.post(new Runnable() {public void run() {NotificationManagerInternal nm = LocalServices.getService(NotificationManagerInternal.class);if (nm == null) {return;}// Record whether the package has permission to notify the usermFgsHasNotificationPermission = nm.areNotificationsEnabledForPackage(localPackageName, appUid);}});
}

前台服务任务管理器

介绍

前台任务管理器
无论app的目标sdk版本是多少，android 13上都允许用户从抽屉式通知栏中停止前台服务（整个应用）。停止原因在ApplicationExitInfo表现为REASON_USER_REQUESTED。

豁免

以下应用可以运行前台服务，而完全不会显示在任务管理器中：

系统级应用
安全应用，即具有 ROLE_EMERGENCY 角色的应用
处于演示模式的设备上的应用

当以下类型的应用运行前台服务时，它们会显示在 FGS 任务管理器中，但应用名称旁边没有可以供用户按的停止按钮：

设备所有者应用
资料所有者应用
常驻应用
具有 ROLE_DIALER 角色的应用
- 处于doze白名单应用

代码

// FgsManagerController.kt
fun updateUiControl() {uiControl = when (activityManager.getBackgroundRestrictionExemptionReason(uid)) {// 不显示在任务管理器中PowerExemptionManager.REASON_SYSTEM_UID,PowerExemptionManager.REASON_DEVICE_DEMO_MODE -> UIControl.HIDE_ENTRY// 显示在任务管理器，但是没有停止按钮PowerExemptionManager.REASON_ALLOWLISTED_PACKAGE,PowerExemptionManager.REASON_DEVICE_OWNER,PowerExemptionManager.REASON_DISALLOW_APPS_CONTROL,PowerExemptionManager.REASON_DPO_PROTECTED_APP,PowerExemptionManager.REASON_PROFILE_OWNER,PowerExemptionManager.REASON_PROC_STATE_PERSISTENT,PowerExemptionManager.REASON_PROC_STATE_PERSISTENT_UI,PowerExemptionManager.REASON_ROLE_DIALER,PowerExemptionManager.REASON_SYSTEM_MODULE -> UIControl.HIDE_BUTTON// 正常情况else -> UIControl.NORMAL}uiControlInitialized = true
}

// AppRestrictionController.java
/*** @return The reason code of whether or not the given UID should be exempted from background* restrictions here.** <p>* Note: Call it with caution as it'll try to acquire locks in other services.* </p>*/
@ReasonCode
int getBackgroundRestrictionExemptionReason(int uid) {// uid < 10000if (UserHandle.isCore(uid)) {return REASON_SYSTEM_UID;}// Whitelist system appsif (isOnSystemDeviceIdleAllowlist(uid)) {return REASON_SYSTEM_ALLOW_LISTED;}// Whitelist user apps , doze白名单，可联系功耗同学添加if (isOnDeviceIdleAllowlist(uid)) {return REASON_ALLOWLISTED_PACKAGE;}// 暂无研究final ActivityManagerInternal am = mInjector.getActivityManagerInternal();if (am.isAssociatedCompanionApp(UserHandle.getUserId(uid), uid)) {return REASON_COMPANION_DEVICE_MANAGER;}// 处于演示模式的设备上的应用if (UserManager.isDeviceInDemoMode(mContext) {return REASON_DEVICE_DEMO_MODE;}final int userId = UserHandle.getUserId(uid);if (mInjector.getUserManagerInternal().hasUserRestriction(UserManager.DISALLOW_APPS_CONTROL, userId)) {return REASON_DISALLOW_APPS_CONTROL;}// 设备所有者if (am.isDeviceOwner(uid)) {return REASON_DEVICE_OWNER;}// 资料所有者if (am.isProfileOwner(uid)) {return REASON_PROFILE_OWNER;}// persistent常驻应用final int uidProcState = am.getUidProcessState(uid);if (uidProcState <= PROCESS_STATE_PERSISTENT) {return REASON_PROC_STATE_PERSISTENT;} else if (uidProcState <= PROCESS_STATE_PERSISTENT_UI) {return REASON_PROC_STATE_PERSISTENT_UI;}final String[] packages = mInjector.getPackageManager().getPackagesForUid(uid);if (packages != null) {final AppOpsManager appOpsManager = mInjector.getAppOpsManager();final PackageManagerInternal pm = mInjector.getPackageManagerInternal();final AppStandbyInternal appStandbyInternal = mInjector.getAppStandbyInternal();for (String pkg : packages) {// VPNif (appOpsManager.checkOpNoThrow(AppOpsManager.OP_ACTIVATE_VPN,uid, pkg) == AppOpsManager.MODE_ALLOWED) {return REASON_OP_ACTIVATE_VPN;} else if (appOpsManager.checkOpNoThrow(AppOpsManager.OP_ACTIVATE_PLATFORM_VPN,uid, pkg) == AppOpsManager.MODE_ALLOWED) {return REASON_OP_ACTIVATE_PLATFORM_VPN;} else if (isSystemModule(pkg)) {return REASON_SYSTEM_MODULE;} else if (isCarrierApp(pkg)) {return REASON_CARRIER_PRIVILEGED_APP;} else if (isExemptedFromSysConfig(pkg)) {return REASON_SYSTEM_ALLOW_LISTED;} else if (mConstantsObserver.mBgRestrictionExemptedPackages.contains(pkg)) {return REASON_SYSTEM_ALLOW_LISTED;} else if (pm.isPackageStateProtected(pkg, userId)) {return REASON_DPO_PROTECTED_APP;} else if (appStandbyInternal.isActiveDeviceAdmin(pkg, userId)) {return REASON_ACTIVE_DEVICE_ADMIN;}}}// dialer角色if (isRoleHeldByUid(RoleManager.ROLE_DIALER, uid)) {return REASON_ROLE_DIALER;}if (isRoleHeldByUid(RoleManager.ROLE_EMERGENCY, uid)) {return REASON_ROLE_EMERGENCY;}return REASON_DENIED;
}

测试

adb shell dumpsys deviceidle // 查看是否在doze白名单，可以不显示停止按钮
adb shell cmd activity stop-app PACKAGE_NAME

监控长期运行的前台服务

介绍

长时间运行服务通知
如果系统检测到您的应用长时间运行某项前台服务（在 24 小时的时间段内至少运行 20 小时），便会发送通知邀请用户与前台服务 (FGS) 任务管理器互动。该通知包含以下内容：

APP is running in the background for a long time. Tap to review.

如果前台服务的类型为 FOREGROUND_SERVICE_TYPE_MEDIA_PLAYBACK 或 FOREGROUND_SERVICE_TYPE_LOCATION，系统将不会显示此通知。

代码

谷歌提交记录

commit 64ac1a923065d38fa33789b315c716f4c93312fc
Author: Jing Ji <jji@google.com>
Date:   Sat Dec 11 03:14:45 2021 -0800Monitor long-running foreground servicesIf a certain package has foreground services running for a long time,say the accumulated durations over last X hours are more than Y hours,system will post a notification to remind the user.Some type of apps are subjected to be exempted, i.e. if it's alreadyin the device idle allowlist. More exemption could be added inthe follow-up CLs.Bug: 200326767Bug: 203105544Test: atest FrameworksMockingServicesTests:BackgroundRestrictionTestChange-Id: I3a8f34c33e7a533240abc7cf4fa569a0956eec73

主要逻辑在新增的类：

//  监控滥用（长时间运行）FGS 的跟踪器
frameworks/base/services/core/java/com/android/server/am/AppFGSTracker.java

显示长时间运行通知

static final long DEFAULT_BG_FGS_LONG_RUNNING_THRESHOLD = 20 * ONE_HOUR;

对应的流程如下：

移除长时间运行通知

若FGS已经停止运行则取消该通知