feat: foreground service & automatic reconnecting

app/build.gradle

@@ -22,6 +22,8 @@ android {
 
         buildConfigField "String", "API_BASE_URL", "\"${props['apiBaseUrl']}\""
         buildConfigField "String", "API_KEY", "\"${props['apiKey']}\""
+        buildConfigField "String", "SERVICE_UUID", "\"6e400001-b5a3-f393-e1a9-e50e24dcac9e\""
+        buildConfigField "String", "CHAR_UUID", "\"6e400005-b5a3-f393-e1a9-e50e24dcac9e\""
     }
 
     buildTypes {

app/src/main/AndroidManifest.xml

@@ -17,6 +17,9 @@
         android:name="android.permission.ACCESS_FINE_LOCATION"
         android:maxSdkVersion="30" />
 
+    <uses-permission
+        android:name="android.permission.FOREGROUND_SERVICE" />
+
     <uses-permission
         android:name="android.permission.BLUETOOTH_SCAN"
         android:usesPermissionFlags="neverForLocation"
@@ -39,7 +42,6 @@
         <activity
             android:name=".MainActivity"
             android:exported="true"
-            android:label="@string/app_name"
             android:theme="@style/Theme.SensorTestingApp">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
@@ -47,6 +49,7 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <service android:name=".BLEService"  android:foregroundServiceType="connectedDevice" />
     </application>
 
 </manifest>

app/src/main/java/com/example/sensortestingapp/BLEService.kt

@@ -0,0 +1,69 @@
+package com.example.sensortestingapp
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import android.os.IBinder
+import androidx.core.app.NotificationCompat
+import androidx.core.content.ContextCompat
+
+class BLEService : Service() {
+    private val CHANNEL_ID = "BLEService Kotlin"
+
+    companion object {
+
+        fun startService(context: Context, message: String) {
+            val startIntent = Intent(context,
+                BLEService::class.java)
+            startIntent.putExtra("inputExtra", message)
+            ContextCompat.startForegroundService(context, startIntent)
+        }
+
+        fun stopService(context: Context) {
+            val stopIntent = Intent(context, BLEService::class.java)
+            context.stopService(stopIntent)
+        }
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+
+        //do heavy work on a background thread
+        val input = intent?.getStringExtra("inputExtra")
+        createNotificationChannel()
+        val notificationIntent = Intent(this, MainActivity::class.java)
+
+        val pendingIntent: PendingIntent =
+            Intent(this, MainActivity::class.java).let { notificationIntent ->
+                PendingIntent.getActivity(this, 0, notificationIntent,
+                    PendingIntent.FLAG_IMMUTABLE)
+            }
+        val notification = NotificationCompat.Builder(this, CHANNEL_ID)
+            .setContentTitle("BLEService Service Kotlin Example")
+            .setContentText(input)
+            //.setSmallIcon(R.drawable.ic_notification)
+            .setContentIntent(pendingIntent)
+            .build()
+
+        startForeground(1, notification)
+        //stopSelf();
+        return START_NOT_STICKY
+    }
+
+    override fun onBind(intent: Intent): IBinder? {
+        return null
+    }
+
+    private fun createNotificationChannel() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            val serviceChannel = NotificationChannel(CHANNEL_ID, "BLEService Service Channel",
+                NotificationManager.IMPORTANCE_DEFAULT)
+
+            val manager = getSystemService(NotificationManager::class.java)
+            manager!!.createNotificationChannel(serviceChannel)
+        }
+    }
+}

app/src/main/java/com/example/sensortestingapp/ConnectionManager.kt

@@ -1,6 +1,7 @@
 package com.example.sensortestingapp
 
 import android.annotation.SuppressLint
+import android.app.Service
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.BluetoothDevice
 import android.bluetooth.BluetoothDevice.BOND_BONDED
@@ -14,12 +15,14 @@ import android.bluetooth.BluetoothGattDescriptor
 import android.bluetooth.BluetoothProfile
 import android.bluetooth.BluetoothProfile.STATE_DISCONNECTED
 import android.bluetooth.le.ScanCallback
+import android.bluetooth.le.ScanFilter
 import android.bluetooth.le.ScanResult
 import android.bluetooth.le.ScanSettings
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
+import android.os.ParcelUuid
 import android.util.Log
 import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
@@ -198,7 +201,7 @@ fun ByteArray.toHexString(): String =
     joinToString(separator = "", prefix = "0x") { String.format("%02X", it) }
 
 @SuppressLint("MissingPermission")
-class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
+class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter)  {
 
     private val deviceGattMap = ConcurrentHashMap<BluetoothDevice, BluetoothGatt>()
     private val operationQueue = ConcurrentLinkedQueue<BleOperationType>()
@@ -209,6 +212,8 @@ class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
         .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
         .build()
 
+    private val scanFilters = listOf( ScanFilter.Builder().setServiceUuid(ParcelUuid.fromString(BuildConfig.SERVICE_UUID)).build())
+
     private val bleScanner by lazy {
         bleAdapter.bluetoothLeScanner
     }
@@ -274,6 +279,8 @@ class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
             broadcastReceiver,
             IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED)
         )
+
+
     }
 
     var isScanning = false
@@ -307,7 +314,7 @@ class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
     fun startScan() {
         if (!isScanning) {
             isScanning = true
-            bleScanner.startScan(null, scanSettings, scanCallback)
+            bleScanner.startScan( null, scanSettings, scanCallback)
         }
     }
 
@@ -428,7 +435,7 @@ class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
             with(operation) {
                 Log.w("ConnectionManager", "Connecting to ${device.address}")
                 device.connectGatt(
-                    context, false, callback, BluetoothDevice.TRANSPORT_LE
+                    context, true, callback, BluetoothDevice.TRANSPORT_LE
                 )
             }
             return
@@ -520,6 +527,7 @@ class ConnectionManager(val context: Context, bleAdapter: BluetoothAdapter) {
 
             is SetNotification -> with(operation) {
                 val characteristic = gatt.getService(serviceId)?.getCharacteristic(charId);
+
                 if (characteristic == null) {
                     Log.e("ConnectionManager", "Char $charId (${serviceId}) not found!")
                     signalEndOfOperation(operation)

app/src/main/java/com/example/sensortestingapp/KirbyDevice.kt

@@ -25,9 +25,8 @@ import java.util.UUID
 import java.util.stream.Collectors
 
 
-// Kirby service uuid: 6e400001-b5a3-f393-e1a9-e50e24dcac9e
+private val SERVICE_UUID = UUID.fromString(BuildConfig.SERVICE_UUID)
-private val DEMO_SERVICE_UUID = UUID.fromString("6e400001-b5a3-f393-e1a9-e50e24dcac9e")
+private val CHAR_UUID = UUID.fromString(BuildConfig.CHAR_UUID)
-private val DEMO_CHAR_UUID = UUID.fromString("6e400005-b5a3-f393-e1a9-e50e24dcac9e")
 
 enum class DeviceStatus {
     CONNECTED, BONDED, SUBSCRIBED, MISSING
@@ -40,8 +39,27 @@ class KirbyDevice(
     private val bleDevice: BluetoothDevice,
     private val onStateChange: (device: KirbyDevice) -> Unit,
 
-) : BleListener(bleDevice.address), DeviceListEntry {
+    ) : BleListener(bleDevice.address), DeviceListEntry {
-    private val queue : RequestQueue  = Volley.newRequestQueue(context)
+    private val queue: RequestQueue = Volley.newRequestQueue(context)
+
+    fun subscribe() {
+
+        connectionManager.enableNotification(
+            bleDevice, SERVICE_UUID, CHAR_UUID
+        )
+    }
+
+    fun readIaq() {
+        connectionManager.readChar(bleDevice, SERVICE_UUID, CHAR_UUID)
+    }
+
+    override fun onSuccessfulCharRead(
+        gatt: BluetoothGatt,
+        characteristic: BluetoothGattCharacteristic
+    ) {
+        addMeasurement(characteristic)
+        onStateChange(this)
+    }
 
     override fun onScanResult(callbackType: Int, result: ScanResult) {
         rssi = result.rssi
@@ -51,6 +69,7 @@ class KirbyDevice(
     override fun onConnect(gatt: BluetoothGatt) {
         statuses.add(DeviceStatus.CONNECTED)
         statuses.remove(DeviceStatus.MISSING)
+
         onStateChange(this)
     }
 
@@ -65,14 +84,6 @@ class KirbyDevice(
         onStateChange(this)
     }
 
-    override fun onSuccessfulCharRead(
-        gatt: BluetoothGatt,
-        characteristic: BluetoothGattCharacteristic
-    ) {
-        addMeasurement(characteristic)
-        onStateChange(this)
-    }
-
     override fun onCharChange(gatt: BluetoothGatt, characteristic: BluetoothGattCharacteristic) {
         addMeasurement(characteristic)
         onStateChange(this)
@@ -82,6 +93,7 @@ class KirbyDevice(
         gatt: BluetoothGatt,
         descriptor: BluetoothGattDescriptor,
     ) {
+
         statuses.add(DeviceStatus.SUBSCRIBED)
         onStateChange(this)
     }
@@ -116,25 +128,23 @@ class KirbyDevice(
     override var rssi: Int? = null
 
     private fun addMeasurement(characteristic: BluetoothGattCharacteristic) {
-        if (characteristic.service.uuid == DEMO_SERVICE_UUID && characteristic.uuid == DEMO_CHAR_UUID) {
+        val hexPayload = characteristic.value.toHexString()
-
+        val payload = Payload(hexPayload)
-            val hexPayload = characteristic.value.toHexString()
+        val base64Payload = Base64.getEncoder().encodeToString(characteristic.value)
-            val payload = Payload(hexPayload)
+        Log.i("BleListener", "Char received: $payload")
-            val base64Payload = Base64.getEncoder().encodeToString(characteristic.value)
+        measurements.add(payload)
-            Log.i("BleListener", "Demo char received: $payload")
+        publishMeasurement(base64Payload)
-            measurements.add(payload)
-            publishMeasurement(base64Payload)
-
-        }
     }
 
     private fun publishMeasurement(payload: String) {
-        val accessKey = BuildConfig.API_BASE_URL
+        val accessKey = BuildConfig.API_KEY
-        val url = BuildConfig.API_KEY
+        val url = BuildConfig.API_BASE_URL
-        val eui =  "0000${bleDevice.address}"
+        val eui = "0000${bleDevice.address.replace(":", "")}"
 
         val postData = JSONObject()
+
         try {
+            Log.i("POST", "Transmitting for $eui: $payload")
             postData.put("accessKey", accessKey)
             postData.put("metricPayload", payload)
             postData.put("eui", eui)
@@ -145,7 +155,7 @@ class KirbyDevice(
         val request = JsonObjectRequest(
             Request.Method.POST, url, postData,
             { response ->
-                Log.i("sendDataResponse","Response is: $response")
+                Log.i("sendDataResponse", "Response is: $response")
             }
         ) { error -> error.printStackTrace() }
 
@@ -257,7 +267,7 @@ class KirbyDevice(
                 }
 
                 override fun execute() {
-                    connectionManager.readChar(bleDevice, DEMO_SERVICE_UUID, DEMO_CHAR_UUID)
+                    readIaq()
                 }
             })
 
@@ -272,9 +282,7 @@ class KirbyDevice(
                     }
 
                     override fun execute() {
-                        connectionManager.enableNotification(
+                        subscribe()
-                            bleDevice, DEMO_SERVICE_UUID, DEMO_CHAR_UUID
-                        )
                     }
                 })
             }
@@ -307,7 +315,7 @@ class KirbyDevice(
 
                 override fun execute() {
                     connectionManager.disableNotification(
-                        bleDevice, DEMO_SERVICE_UUID, DEMO_CHAR_UUID
+                        bleDevice, SERVICE_UUID, CHAR_UUID
                     )
                 }
             })
@@ -341,7 +349,6 @@ data class Payload(
 )
 
 
-
 fun bytesToUInt16(arr: ByteArray, start: Int): Int {
     return ByteBuffer.wrap(arr, start, 2)
         .order(ByteOrder.LITTLE_ENDIAN).short.toInt() and 0xFFFF
@@ -371,21 +378,18 @@ private fun payloadToMeasurements(payload: Payload): List<Measurement> {
         override fun getIcon(): Int? {
             return R.drawable.baseline_access_time_24
         }
-    },
+    }, object : Measurement {
-        object : Measurement {
+        override fun getLabel(): String {
-            override fun getLabel(): String {
+            return "Payload"
-                return "Payload"
-            }
-
-            override fun getFormattedValue(): String {
-                return payload.payload
-            }
-
-            override fun getIcon(): Int? {
-                return null
-            }
-
         }
 
-        )
+        override fun getFormattedValue(): String {
+            return payload.payload
+        }
+
+        override fun getIcon(): Int? {
+            return null
+        }
+    }
+    )
 }

app/src/main/java/com/example/sensortestingapp/MainActivity.kt

@@ -75,7 +75,7 @@ class MainActivity : AppCompatActivity() {
 
         setSupportActionBar(binding.toolbar)
 
-
+        BLEService.startService(applicationContext, "hello ble service")
 
         binding.fab.setOnClickListener { view ->
             if (!hasRequiredRuntimePermissions()) {
@@ -103,10 +103,10 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun isKirbyDevice(device: BluetoothDevice): Boolean {
-        Log.i("kby", "found device ${device.name}")
         return (device.name ?: "").lowercase().contains("kirby")
     }
 
+
     private fun setupDevicesList() {
         binding.devicesList.apply {
             adapter = deviceListAdapter
@@ -134,7 +134,8 @@ class MainActivity : AppCompatActivity() {
 
     private fun addBondedDevices(): Unit {
         bluetoothAdapter.bondedDevices.filter { isKirbyDevice(it) }.forEach {
-            newKirbyDevice(it)
+            val kirbyDevice = newKirbyDevice(it)
+            kirbyDevice.subscribe()
         }
     }
 
@@ -179,13 +180,15 @@ class MainActivity : AppCompatActivity() {
 
     private fun newKirbyDevice(bleDevice: BluetoothDevice): KirbyDevice {
 
-        val device = KirbyDevice( this.applicationContext, connectionManager, bleDevice) {
+        val device = KirbyDevice(this.applicationContext, connectionManager, bleDevice) {
             val i = kirbyDevices.indexOfFirst { d -> d === it }
             runOnUiThread {
                 deviceListAdapter.notifyItemChanged(i)
             }
         }
         connectionManager.register(device)
+        connectionManager.connect(bleDevice)
+        connectionManager.discoverServices(bleDevice)
         kirbyDevices.add(device)
         deviceListAdapter.notifyItemInserted(kirbyDevices.size - 1)
         return device