Foreground service example to keep call running in background (#175)

@@ -12,4 +12,8 @@
         android:name="android.permission.BLUETOOTH_ADMIN"
         android:maxSdkVersion="30" />
 
+    <application>
+        <service android:name="io.livekit.android.sample.service.ForegroundService" />
+    </application>
+
 </manifest>
\ No newline at end of file

@@ -3,6 +3,7 @@ package io.livekit.android.sample
 import android.app.Application
 import android.content.Intent
 import android.media.projection.MediaProjectionManager
+import android.os.Build
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
@@ -22,6 +23,7 @@ import io.livekit.android.room.track.CameraPosition
 import io.livekit.android.room.track.LocalScreencastVideoTrack
 import io.livekit.android.room.track.LocalVideoTrack
 import io.livekit.android.room.track.Track
+import io.livekit.android.sample.service.ForegroundService
 import io.livekit.android.util.flow
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
@@ -119,6 +121,16 @@ class CallViewModel(
             }
             connectToRoom()
         }
+
+
+        // Start a foreground service to keep the call from being interrupted if the
+        // app goes into the background.
+        val foregroundServiceIntent = Intent(application, ForegroundService::class.java)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            application.startForegroundService(foregroundServiceIntent)
+        } else {
+            application.startService(foregroundServiceIntent)
+        }
     }
 
     private suspend fun connectToRoom() {
@@ -216,6 +228,11 @@ class CallViewModel(
         super.onCleared()
         room.disconnect()
         room.release()
+
+        // Clean up foreground service
+        val application = getApplication<Application>()
+        val foregroundServiceIntent = Intent(application, ForegroundService::class.java)
+        application.stopService(foregroundServiceIntent)
     }
 
     fun setMicEnabled(enabled: Boolean) {

+package io.livekit.android.sample.service
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import android.os.IBinder
+import androidx.annotation.RequiresApi
+import androidx.core.app.NotificationCompat
+
+/**
+ * A foreground service is required for screen capture on API level Q (29) and up.
+ * This a simple default foreground service to display a notification while screen
+ * capturing.
+ */
+
+open class ForegroundService : Service() {
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            createNotificationChannel()
+        }
+
+        val actualNotification =
+            NotificationCompat.Builder(this, DEFAULT_CHANNEL_ID)
+                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
+                .build()
+
+        startForeground(DEFAULT_NOTIFICATION_ID, actualNotification)
+        return START_NOT_STICKY
+    }
+    
+    @RequiresApi(Build.VERSION_CODES.O)
+    private fun createNotificationChannel() {
+        val channel = NotificationChannel(
+            DEFAULT_CHANNEL_ID,
+            "Foreground",
+            NotificationManager.IMPORTANCE_LOW
+        )
+        val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        notificationManager.createNotificationChannel(channel)
+    }
+
+    override fun onBind(intent: Intent?): IBinder? {
+        return null // not used.
+    }
+
+    companion object {
+        const val DEFAULT_NOTIFICATION_ID = 3456
+        const val DEFAULT_CHANNEL_ID = "livekit_example_foreground"
+    }
+}
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