[O] Split code into service

app/src/main/AndroidManifest.xml

@@ -7,6 +7,7 @@
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
 
     <uses-feature android:name="android.hardware.bluetooth_le" android:required="true" />
 
@@ -39,6 +40,7 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <service android:name=".MyService"/>
     </application>
 
 </manifest>

app/src/main/java/org/hydev/wearsync/Extensions.kt

@@ -1,6 +1,7 @@
 package org.hydev.wearsync
 
 import android.app.Activity
+import android.app.Service
 import android.bluetooth.BluetoothManager
 import android.content.Context
 import android.content.Intent
@@ -17,6 +18,7 @@ import com.influxdb.client.domain.WritePrecision
 import com.influxdb.client.kotlin.InfluxDBClientKotlin
 import com.influxdb.client.kotlin.InfluxDBClientKotlinFactory
 import kotlin.reflect.KProperty
+import kotlin.reflect.full.isSubclassOf
 
 
 fun View.snack(msg: String) = Snackbar.make(this, msg, Snackbar.LENGTH_LONG)
@@ -62,8 +64,15 @@ val Context.prefs get() = object : Prefs {
     }
 }
 
-inline fun <reified T : Activity> Context.intent() = Intent(this, T::class.java)
-inline fun <reified T : Activity> Context.act() = startActivity(intent<T>())
+inline fun <reified T> Context.intent() = Intent(this, T::class.java)
+inline fun <reified T> Context.act()
+{
+    if (T::class.isSubclassOf(Activity::class))
+        startActivity(intent<T>())
+    else if (T::class.isSubclassOf(Service::class))
+        startService(intent<T>())
+    else TODO("Unimplemented: ${T::class}")
+}
 fun ComponentActivity.actCallback(fn: ActivityResultCallback<ActivityResult>) =
     registerForActivityResult(ActivityResultContracts.StartActivityForResult(), fn)
 

app/src/main/java/org/hydev/wearsync/MainActivity.kt

@@ -1,6 +1,8 @@
 package org.hydev.wearsync
 
 import android.annotation.SuppressLint
+import android.app.NotificationChannel
+import android.app.NotificationManager
 import android.bluetooth.BluetoothAdapter
 import android.content.Intent
 import android.graphics.Color
@@ -13,15 +15,18 @@ import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.influxdb.client.kotlin.InfluxDBClientKotlin
 import kotlinx.coroutines.*
-import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.flow.consumeAsFlow
 import org.hydev.wearsync.ActivityPermissions.Companion.hasPermissions
-import org.hydev.wearsync.bles.BluetoothHandler.Companion.ble
 import org.hydev.wearsync.databinding.ActivityMainBinding
 import java.util.*
 
 class MainActivity : AppCompatActivity()
 {
+    companion object {
+        var instance: MainActivity? = null
+    }
+
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+
     lateinit var binding: ActivityMainBinding
     lateinit var influx: InfluxDBClientKotlin
 
@@ -41,15 +46,24 @@ class MainActivity : AppCompatActivity()
     {
         super.onCreate(savedInstanceState)
 
+        // Bind activity
         binding = ActivityMainBinding.inflate(layoutInflater)
         setContentView(binding.root)
         setSupportActionBar(binding.toolbar)
 
+        // Create recycler
         binding.content.recycler.let {
             it.adapter = RecordAdapter(records)
             it.layoutManager = LinearLayoutManager(this)
         }
 
+        // Create notification channel
+        val chan = NotificationChannel(MyService.NOTIF_CHANNEL_ID, "Keep-alive Notification",
+            NotificationManager.IMPORTANCE_MIN)
+        getSysServ<NotificationManager>().createNotificationChannel(chan)
+
+        instance = this
+
         if (!hasPermissions()) permissionCallback.launch(intent<ActivityPermissions>())
         else afterPermissions()
     }
@@ -83,7 +97,7 @@ class MainActivity : AppCompatActivity()
         binding.content.tvDevice.text = "Configured Device: ${prefs.chosenDevice}"
         binding.content.tvValue.text = "Service started!"
 
-        startCollect()
+        act<MyService>()
     }
 
     override fun onResume()
@@ -119,7 +133,6 @@ class MainActivity : AppCompatActivity()
         }
     }
 
-    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
     private val records = ArrayList<Any>()
 
     class RecordAdapter(val records: List<Any>) : RecyclerView.Adapter<RecordAdapter.ViewHolder>() {
@@ -154,24 +167,4 @@ class MainActivity : AppCompatActivity()
         records.add(t)
         runOnUiThread { binding.content.recycler.adapter?.notifyDataSetChanged() }
     }
-
-    fun startCollect()
-    {
-        collect(ble.heartRateChannel)
-        collect(ble.batteryChannel)
-    }
-
-    private fun <T : Any> collect(channel: Channel<T>) {
-        scope.launch {
-            channel.consumeAsFlow().collect {
-                try {
-                    addRecord(it)
-                    influx add it
-                }
-                catch (e: Exception) {
-                    addRecord(e)
-                }
-            }
-        }
-    }
 }

app/src/main/java/org/hydev/wearsync/MyService.kt

@@ -0,0 +1,71 @@
+package org.hydev.wearsync
+
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Intent
+import androidx.core.app.NotificationCompat
+import com.influxdb.client.kotlin.InfluxDBClientKotlin
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.launch
+import org.hydev.wearsync.bles.BluetoothHandler.Companion.ble
+
+class MyService : Service()
+{
+    private lateinit var influx: InfluxDBClientKotlin
+
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+
+    override fun onBind(intent: Intent?) = null
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int
+    {
+        influx = prefs.createInflux()
+        startCollect()
+
+        startForeground()
+        return super.onStartCommand(intent, flags, startId)
+    }
+
+    fun startCollect()
+    {
+        collect(ble.heartRateChannel)
+        collect(ble.batteryChannel)
+    }
+
+    private fun <T : Any> collect(channel: Channel<T>) {
+        scope.launch {
+            channel.consumeAsFlow().collect {
+                try {
+                    MainActivity.instance?.addRecord(it)
+                    influx add it
+                }
+                catch (e: Exception) {
+                    MainActivity.instance?.addRecord(e)
+                }
+            }
+        }
+    }
+
+    private fun startForeground()
+    {
+        val notificationIntent = Intent(this, MainActivity::class.java)
+        val pendingIntent = PendingIntent.getActivity(this, 0,
+            notificationIntent, PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT)
+        startForeground(NOTIF_ID, NotificationCompat.Builder(this, NOTIF_CHANNEL_ID)
+                .setOngoing(true)
+                .setSmallIcon(R.drawable.ic_watch_24)
+                .setContentTitle("🐱 Running!")
+                .setContentIntent(pendingIntent)
+                .build()
+        )
+    }
+
+    companion object
+    {
+        private const val NOTIF_ID = 1
+        const val NOTIF_CHANNEL_ID = "Channel_Id"
+    }
+}