致命的安卓12：异常：由于mAllowStartForeground为假，startForegroundService()不允许。

Question 1

我注意到Pixel 5和Pixel 4a（都在安卓12系统上）有一个例外（Firebase Crashlytics），其他设备没有，只发生了两次，每个设备一次。

这是什么意思？安卓11和12有相同的前台服务工作规则，但安卓11没有问题。这是Pixel的一个错误吗？

来自Firebase Crashlytics。

Fatal Exception: android.app.ForegroundServiceStartNotAllowedException
startForegroundService() not allowed due to mAllowStartForeground false: service com.*.*/.service.RecorderService
android.app.ForegroundServiceStartNotAllowedException$1.createFromParcel (ForegroundServiceStartNotAllowedException.java:54)
androidx.core.content.ContextCompat.startForegroundService (ContextCompat.java:6)
MyAppPackageHidden.service.RecorderService$Companion.startService (RecorderService.java:2)
MyAppPackageHidden.ui.rec.RecActivity$getConnectionRecorderService$1.onServiceConnected (RecActivity.java:4)
android.app.LoadedApk$ServiceDispatcher.doConnected (LoadedApk.java:2077)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1003)
Fatal Exception: android.app.ForegroundServiceStartNotAllowedException: startForegroundService() not allowed due to mAllowStartForeground false: service MyAppPackageHidden/.service.RecorderService
       at android.app.ForegroundServiceStartNotAllowedException$1.createFromParcel(ForegroundServiceStartNotAllowedException.java:54)
       at android.app.ForegroundServiceStartNotAllowedException$1.createFromParcel(ForegroundServiceStartNotAllowedException.java:50)
       at android.os.Parcel.readParcelable(Parcel.java:3333)
       at android.os.Parcel.createExceptionOrNull(Parcel.java:2420)
       at android.os.Parcel.createException(Parcel.java:2409)
       at android.os.Parcel.readException(Parcel.java:2392)
       at android.os.Parcel.readException(Parcel.java:2334)
       at android.app.IActivityManager$Stub$Proxy.startService(IActivityManager.java:5971)
       at android.app.ContextImpl.startServiceCommon(ContextImpl.java:1847)
       at android.app.ContextImpl.startForegroundService(ContextImpl.java:1823)
       at android.content.ContextWrapper.startForegroundService(ContextWrapper.java:779)
       at androidx.core.content.ContextCompat$Api26Impl.startForegroundService(ContextCompat.java)
       at androidx.core.content.ContextCompat.startForegroundService(ContextCompat.java:6)
       at MyAppPackageHidden.service.RecorderService$Companion.startService(RecorderService.java:2)
       at MyAppPackageHidden.ui.rec.RecActivity$getConnectionRecorderService$1.onServiceConnected(RecActivity.java:4)
       at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:2077)
       at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:2110)
       at android.os.Handler.handleCallback(Handler.java:938)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loopOnce(Looper.java:201)
       at android.os.Looper.loop(Looper.java:288)
       at android.app.ActivityThread.main(ActivityThread.java:7838)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by android.os.RemoteException: Remote stack trace:
    at com.android.server.am.ActiveServices.startServiceLocked(ActiveServices.java:691)
    at com.android.server.am.ActiveServices.startServiceLocked(ActiveServices.java:616)
    at com.android.server.am.ActivityManagerService.startService(ActivityManagerService.java:11839)
    at android.app.IActivityManager$Stub.onTransact(IActivityManager.java:2519)
    at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:2498)

Question 2


          
           针对Android 12（API级别31）或更高的应用程序不能在后台运行时启动前台服务，少数特殊情况除外。如果一个应用程序在后台运行时试图启动一个前台服务，而该前台服务不满足其中一种特殊情况，系统会抛出一个ForegroundServiceStartNotAllowedException。
          
          
           
            背景启动限制的豁免
           
          
          
           
            在以下情况下，即使你的应用在后台运行，你的应用也可以启动前台服务。
           
          
          
           Your app transitions from a user-visible state, such as an activity.
          
          
           Your app can start an activity from the background, except for the
case where the app has an activity in the back stack of an existing
task.
          
          
           Your app receives a high-priority message using Firebase Cloud
Messaging.
          
          
           The user performs an action on a UI element related to your app. For
example, they might interact with a bubble, notification, widget, or
activity.
          
          
           Your app invokes an exact alarm to complete an action that the user
requests.
          
          
           Your app is the device's current input method.
          
          
           Your app receives an event that's related to geofencing or activity
recognition transition.
          
          
           After the device reboots and receives the ACTION_BOOT_COMPLETED,
ACTION_LOCKED_BOOT_COMPLETED, or ACTION_MY_PACKAGE_REPLACED intent
action in a broadcast receiver.
          
          
           更多信息请查看
           
            link1
           
           
            link2

Question 3


          
           之前我们是用
           
            Service
           
           来运行后台任务，如备份数据、设置提醒通知等。而之前调用服务的代码将如下所示
          
          Intent serviceIntent = new Intent ( context, BackupService.class );
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    context.startForegroundService ( serviceIntent );
} else {
    context.startService ( serviceIntent );
但是，由于Android 12 - Foreground service launch restrictions，我们将无法调用服务来执行后台任务。要了解有关这一限制的更多信息，请参考安卓12的行为变化.
所以从现在开始，（即）从targetSdk 31 / Android 12+开始，Service只能在应用程序处于前台的时候调用。当应用程序被关闭或进入后台时，使用startForegroundService调用Service将导致ForegroundServiceStartNotAllowedException。因此，要在Android 12及以上版本中执行后台任务，我们需要使用Worker而不是Service。要了解更多关于Worker的信息，请参考Work Requests.
因此，对于以SDK 31/Android 12+为目标的应用程序，调用后台任务的代码将如下。
Intent serviceIntent = new Intent ( context, BackupService.class );
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
    OneTimeWorkRequest request = new OneTimeWorkRequest.Builder ( BackupWorker.class ).addTag ( "BACKUP_WORKER_TAG" ).build ();
    WorkManager.getInstance ( context ).enqueue ( request );
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    context.startForegroundService ( serviceIntent );
} else {
    context.startService ( serviceIntent );
替换代码11】(Existing)的示例代码。
public class BackupService extends Service {
    private static final String TAG = "BackupService";
    @Nullable
    @Override
    public IBinder onBind ( Intent intent ) {
        return null;
    @Override
    public int onStartCommand ( Intent intent, int flags, int startId ) {
        Log.d ( TAG, "onStartCommand" );
        startForeground ( BACKUP_SERVICE_NOTIFICATION_ID, createServiceNotification () );
        //call methods to perform background task
        return super.onStartCommand ( intent, flags, startId );
替换代码13】的示例代码（新添加）。
public class BackupWorker extends Worker {
    private static final String TAG = "BackupWorker";
    public BackupWorker ( @NonNull Context context, @NonNull WorkerParameters workerParams ) {
        super ( context, workerParams );
    @NonNull
    @Override
    public Result doWork () {
        //call methods to perform background task
        return Result.success ();
请确保在模块级的gradle文件中添加以下依赖项
implementation 'androidx.work:work-runtime:2.7.1'
implementation 'com.google.guava:guava:27.0.1-android'
I have tested the above code working with Android 5, Android 8, Android 11 & Android 12. Working as expected in my case.




    

希望这个解决方案能帮助那些针对SDK 31/Android 12+的应用程序的人。

Question 4


          
           
            
             
              
               
                在我的案例中，我们使用一个做SIP通信（VoIP）的服务，我们正在启动一个前台服务来做时间敏感的操作（如注册）或在运行SIP呼叫时。这些任务不能在
                
                 Worker
                
                中运行。
               
               
                为了处理这个用例。
                
                 Android允许你声明你的服务的"
                 
                  foregroundServiceType
                 
                 "，有些类型允许从后台创建前台服务
                
                .另一个值得注意的用例是媒体播放。

Question 5


          
           
            
             
              
               
                我们可以把这个作为基本解决方案吗？
               
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
                context.startService ( Service_name );
            } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                ContextCompat.startForegroundService(
                        context,
                        Service_name
            } else {
                context.startService ( Service_name );

Question 6


          
           
            
             
              
               
                
                 为了解决这个问题，在安卓12或更高版本中更新你的应用程序的逻辑。
                
                
                 如果你发现你的应用程序在后台运行时启动前台服务，请更新你的应用程序的逻辑，使用
                 
                  工作经理
                 
                 .要查看如何更新你的应用程序的例子，请通过以下方式查看
                 
                  工作经理Sample
                 
                 on GitHub.

Question 7


          
           
            
             
              
               
                
                 我发现的最佳解决方案是通过
                 
                  Android O+
                 
                 上的
                 
                  AlarmManager
                 
                 从后台或设备重启后启动服务。
                
                val mgr = context.getSystemService(Context.ALARM_SERVICE) as AlarmManager
val i = Intent(context, Service::class.java)
val pi = PendingIntent.getForegroundService(context, 0, i, PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE)
val calendar: Calendar = Calendar.getInstance()
calendar.timeInMillis = System.currentTimeMillis()
calendar.add(Calendar.SECOND, 3)
mgr.set(AlarmManager.RTC_WAKEUP, calendar.timeInMillis ,pi)
另外，在NotificationBuilder中增加了。
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {