Jetpack Compose中使用Tinder/Scarlet WebSocket切后台断开问题求解

• 修改Scarlet生命周期绑定 #

  你当前使用的AndroidLifecycle.ofApplicationForeground(application)逻辑为应用退后台时自动触发STOP事件，Scarlet会主动断开连接，这是断连的直接原因。替换为自定义的常驻生命周期即可：

  // 自定义全局常驻生命周期
  object PermanentLifecycle : Lifecycle {
      private val registry = LifecycleRegistry(this).apply {
          currentState = Lifecycle.State.STARTED
      }
      override fun addObserver(observer: LifecycleObserver) = registry.addObserver(observer)
      override fun removeObserver(observer: LifecycleObserver) = registry.removeObserver(observer)
      override fun getCurrentState(): Lifecycle.State = registry.currentState
  }
  

  然后修改Scarlet配置中的lifecycle参数：

  val scarletConfiguration = Scarlet.Configuration(
      // 其余原有配置保持不变
      lifecycle = PermanentLifecycle
  )
  

• 搭配前台服务实现进程保活 #

  Android系统对后台应用有运行限制，仅修改Scarlet配置仍会被系统切断网络或回收进程，需要启动前台服务持有连接：
  1. 补充权限：Android 12+需要新增前台服务类型权限，Android 13+需要申请通知权限：

  <!-- AndroidManifest.xml 补充权限 -->
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
  <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
  

  2. 实现前台服务代码：

  class WebSocketKeepAliveService : Service() {
      @Inject lateinit var messagingService: ScarletMessagingService
      private val serviceScope = CoroutineScope(Dispatchers.IO + SupervisorJob())
      private val NOTIFICATION_ID = 10086
      private val CHANNEL_ID = "websocket_keep_alive"
  
      override fun onCreate() {
          super.onCreate()
          (application as MyApplication).appComponent.inject(this)
          // 创建通知渠道
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
              val channel = NotificationChannel(
                  CHANNEL_ID,
                  "消息连接",
                  NotificationManager.IMPORTANCE_LOW
              ).apply {
                  setShowBadge(false)
              }
              getSystemService(NotificationManager::class.java).createNotificationChannel(channel)
          }
          // 启动前台
          val notification = NotificationCompat.Builder(this, CHANNEL_ID)
              .setContentTitle("后台消息接收中")
              .setContentText("应用正在后台保持连接")
              .setSmallIcon(R.drawable.ic_app_icon)
              .build()
          startForeground(NOTIFICATION_ID, notification)
      }
  
      override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
          // 服务内启动消息监听，不要放在ViewModel中
          messagingService.observeMessage()
              .onEach {
                  Timber.d("收到服务端消息: $it")
                  // 处理消息，可通过广播、EventBus或者SharedFlow传递给UI层
              }
              .launchIn(serviceScope)
          return START_STICKY
      }
  
      override fun onDestroy() {
          super.onDestroy()
          serviceScope.cancel()
      }
  
      override fun onBind(intent: Intent?): IBinder? = null
  }
  

  3. 注册服务：

  <service
      android:name=".WebSocketKeepAliveService"
      android:exported="false"
      android:foregroundServiceType="dataSync" />
  

• 调整OkHttpClient心跳配置 #

  避免服务器或运营商链路长时间无数据主动断开连接，给OkHttpClient添加心跳间隔：

  val okHttpClient = OkHttpClient.Builder()
      .pingInterval(30, TimeUnit.SECONDS) // 每30秒发送一次心跳包
      // 其余原有配置保持不变
      .build()
  

• 调整原有逻辑 #

  移除ViewModel中的消息监听启动逻辑，改为在应用启动后主动启动WebSocketKeepAliveService，ViewModel只需要监听服务传递过来的消息做UI更新即可，避免ViewModel销毁导致监听被取消。

内容的提问来源于stack exchange，提问作者ArtixModernal