[Android, iOS]: Initialization check, no disconnect on closing (#9)

* feat(android, dart): add check for initialization, show proper error messages

* feat(exception): add exception mapper for android and ios

* feat(ios): check initialization in swift

* fix(android): add initialization check for methods, remove disconnect() inside onDetachedFromEngine

* chore: code style, version, changelog

android/src/main/kotlin/com/xenikii/nearby_service/ErrorCodes.kt

@@ -0,0 +1,12 @@
+package com.xenikii.nearby_service
+
+class ErrorCodes {
+    companion object {
+        const val P2P_UNSUPPORTED = "P2P_UNSUPPORTED"
+        const val ERROR = "ERROR"
+        const val BUSY = "BUSY"
+        const val NO_SERVICE_REQUESTS = "NO_SERVICE_REQUESTS"
+        const val UNKNOWN = "UNKNOWN"
+        const val NO_INITIALIZATION = "NO_INITIALIZATION"
+    }
+}

android/src/main/kotlin/com/xenikii/nearby_service/NearbyServiceManager.kt

@@ -87,6 +87,8 @@ class NearbyServiceManager(private var context: Context) {
      * It also may be null.
      */
     fun getCurrentDevice(result: Result) {
+        if (!checkInitialization(result)) return
+
         try {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                 wifiManager.requestDeviceInfo(wifiChannel) { device ->
@@ -119,6 +121,8 @@ class NearbyServiceManager(private var context: Context) {
      * All permissions from [NearbyServicePermissionsHandler] are required.
      */
     fun discover(result: Result) {
+        if (!checkInitialization(result)) return
+
         try {
             wifiManager.discoverPeers(
                 wifiChannel, getActionListener(
@@ -139,6 +143,8 @@ class NearbyServiceManager(private var context: Context) {
      * Stop discovery for peers in Wi-fi Direct scope.
      */
     fun stopDiscovery(result: Result) {
+        if (!checkInitialization(result)) return
+
         wifiManager.stopPeerDiscovery(
             wifiChannel, getActionListener(
                 result,
@@ -152,6 +158,8 @@ class NearbyServiceManager(private var context: Context) {
      * Returns peers from [NearbyServiceBroadcastReceiver].
      */
     fun getPeers(result: Result) {
+        if (!checkInitialization(result)) return
+
         result.success(receiver.peers)
     }
 
@@ -159,6 +167,8 @@ class NearbyServiceManager(private var context: Context) {
      * Returns connection info from [NearbyServiceBroadcastReceiver] in json string.
      */
     fun getConnectionInfo(result: Result) {
+        if (!checkInitialization(result)) return
+
         val info = receiver.wifiInfo?.toJsonString()
         result.success(info)
     }
@@ -167,6 +177,8 @@ class NearbyServiceManager(private var context: Context) {
      * Connects to provided [deviceAddress] in Wi-fi Direct scope.
      */
     fun connect(result: Result, deviceAddress: String) {
+        if (!checkInitialization(result)) return
+
         val config = WifiP2pConfig()
         if (receiver.connectedDevice?.deviceAddress == deviceAddress) {
             Logger.i("Already connected to the device $deviceAddress")
@@ -196,6 +208,8 @@ class NearbyServiceManager(private var context: Context) {
      * Disconnect from a previous device in Wi-fi Direct scope.
      */
     fun disconnect(result: Result? = null) {
+        if (!checkInitialization(result)) return
+
         val actionListener = getActionListener(
             result, "Disconnected from last device", "Failed to disconnect"
         )
@@ -204,6 +218,8 @@ class NearbyServiceManager(private var context: Context) {
     }
 
     fun cancelConnect(result: Result? = null) {
+        if (!checkInitialization(result)) return
+
         val actionListener = getActionListener(
             result,
             "Last connection request was cancelled",
@@ -240,6 +256,31 @@ class NearbyServiceManager(private var context: Context) {
         }
     }
 
+    private fun checkInitialization(result: Result?, shouldLog: Boolean = true): Boolean {
+        try {
+            if (!::wifiManager.isInitialized) {
+                Logger.e("WifiManager is not initialized. Please call 'initialize()' first")
+                result?.success(ErrorCodes.NO_INITIALIZATION)
+                return false
+            }
+            if (!::wifiChannel.isInitialized) {
+                Logger.e("WifiChannel is not initialized. Please call 'initialize()' first")
+                result?.success(ErrorCodes.NO_INITIALIZATION)
+                return false
+            }
+            if (!::receiver.isInitialized) {
+                Logger.e("Broadcast Receiver is not initialized. Please call 'initialize()' first")
+                result?.success(ErrorCodes.NO_INITIALIZATION)
+                return false
+            }
+        } catch (e: Exception) {
+            Logger.e("Failed to check initialization, please call 'initialize()' first")
+            result?.success(ErrorCodes.NO_INITIALIZATION)
+            return false
+        }
+        return true
+    }
+
     private fun getActionListener(
         result: Result?,
         successMessage: String? = null,
@@ -262,11 +303,11 @@ class NearbyServiceManager(private var context: Context) {
                     else -> "An unknown error occurred. Please check the device's Wi-Fi P2P settings and ensure the device supports Wi-Fi P2P."
                 }
                 val stringifyReasonCode = when (reasonCode) {
-                    WifiP2pManager.P2P_UNSUPPORTED -> "P2P_UNSUPPORTED"
-                    WifiP2pManager.ERROR -> "ERROR"
-                    WifiP2pManager.BUSY -> "BUSY"
-                    WifiP2pManager.NO_SERVICE_REQUESTS -> "NO_SERVICE_REQUESTS"
-                    else -> "UNKNOWN"
+                    WifiP2pManager.P2P_UNSUPPORTED -> ErrorCodes.P2P_UNSUPPORTED
+                    WifiP2pManager.ERROR -> ErrorCodes.ERROR
+                    WifiP2pManager.BUSY -> ErrorCodes.BUSY
+                    WifiP2pManager.NO_SERVICE_REQUESTS -> ErrorCodes.NO_SERVICE_REQUESTS
+                    else -> ErrorCodes.UNKNOWN
                 }
                 Logger.e("$errorMessage, Reason code: $reasonCode, Reason: $reason")
                 result?.success(stringifyReasonCode)
@@ -281,6 +322,8 @@ class NearbyServiceManager(private var context: Context) {
 
         val postCallback = object : Runnable {
             override fun run() {
+                if (!checkInitialization(null, false)) return
+
                 handler.post { eventSink?.success("${receiver.peers}") }
                 handler.postDelayed(this, 1000)
             }
@@ -306,6 +349,8 @@ class NearbyServiceManager(private var context: Context) {
 
         val postCallback = object : Runnable {
             override fun run() {
+                if (!checkInitialization(null, false)) return
+
                 handler.post { eventSink?.success(receiver.connectedDevice?.toJsonString()) }
                 handler.postDelayed(this, 1000)
             }
@@ -330,6 +375,8 @@ class NearbyServiceManager(private var context: Context) {
 
         val postCallback = object : Runnable {
             override fun run() {
+                if (!checkInitialization(null, false)) return
+
                 handler.post { eventSink?.success(receiver.wifiInfo?.toJsonString()) }
                 handler.postDelayed(this, 1000)
             }

android/src/main/kotlin/com/xenikii/nearby_service/NearbyServicePlugin.kt

@@ -177,7 +177,6 @@ class NearbyServicePlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
         channel.setMethodCallHandler(null)
         peersChannel.setStreamHandler(null)
         connectedDeviceChannel.setStreamHandler(null)
-        manager.disconnect()
     }
 
     override fun onAttachedToActivity(binding: ActivityPluginBinding) {