Deinitialize in onDetachedFromEngine on Android (#519)

* Deinitialize in onDetachedFromEngine on Android

* Fixed crash with no devices connected
Use current instance as method handler to prevent issues
Fixed some typos

Author: Rexios80

packages/reactive_ble_mobile/android/src/main/kotlin/com/signify/hue/flutterreactiveble/PluginController.kt

@@ -71,6 +71,11 @@ class PluginController {
         bleStatusChannel.setStreamHandler(bleStatusHandler)
     }
 
+    internal fun deinitialize() {
+        scandevicesHandler.stopDeviceScan()
+        deviceConnectionHandler.disconnectAll()
+    }
+
     internal fun execute(call: MethodCall, result: Result) {
         pluginMethods[call.method]?.invoke(call, result) ?: result.notImplemented()
     }
@@ -81,8 +86,7 @@ class PluginController {
     }
 
     private fun deinitializeClient(call: MethodCall, result: Result) {
-        scandevicesHandler.stopDeviceScan()
-        deviceConnectionHandler.disconnectAll()
+        deinitialize()
         result.success(null)
     }
 

packages/reactive_ble_mobile/android/src/main/kotlin/com/signify/hue/flutterreactiveble/ReactiveBlePlugin.kt

@@ -9,22 +9,32 @@ import io.flutter.plugin.common.MethodChannel.Result
 
 class ReactiveBlePlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
     override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
-        initalizePlugin(binding.binaryMessenger, binding.applicationContext)
+        initializePlugin(binding.binaryMessenger, binding.applicationContext, this)
     }
 
     override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
-        // deinitalize logic
+        deinitializePlugin()
     }
 
     companion object {
         lateinit var pluginController: PluginController
+
         @JvmStatic
-        private fun initalizePlugin(messenger: BinaryMessenger, context: Context) {
+        private fun initializePlugin(
+            messenger: BinaryMessenger,
+            context: Context,
+            plugin: ReactiveBlePlugin
+        ) {
             val channel = MethodChannel(messenger, "flutter_reactive_ble_method")
-            channel.setMethodCallHandler(ReactiveBlePlugin())
+            channel.setMethodCallHandler(plugin)
             pluginController = PluginController()
             pluginController.initialize(messenger, context)
         }
+
+        @JvmStatic
+        private fun deinitializePlugin() {
+            pluginController.deinitialize()
+        }
     }
 
     override fun onMethodCall(call: MethodCall, result: Result) {

packages/reactive_ble_mobile/android/src/main/kotlin/com/signify/hue/flutterreactiveble/ble/ReactiveBleClient.kt

@@ -45,7 +45,7 @@ open class ReactiveBleClient(private val context: Context) : BleClient {
 
         lateinit var rxBleClient: RxBleClient
             internal set
-        internal lateinit var activeConnections: MutableMap<String, DeviceConnector>
+        internal var activeConnections = mutableMapOf<String, DeviceConnector>()
     }
 
     override val connectionUpdateSubject: BehaviorSubject<ConnectionUpdate>