Improve V2Ray config/error handling and startup

Add richer error reporting and simplify control flow across core components. Key changes:

- Add errorMessage to ConfigResult and populate it on failures in CoreConfigManager.getV2rayConfig/getV2rayConfig4Speedtest.
- Replace many nullable/boolean error returns in CoreConfigManager with explicit errors (error()/exceptions) and non-null return types; tighten validation (invalid servers, missing assets, parsing errors) and simplify inbound/dns/routing/outbound setup logic.
- Make getInbounds/getRouting/getDns/getOutbounds/getCustomLocalDns/getRoutingUserRule/getBalance non-failing (throw on error) and remove silent try/catch patterns; improve logging and fallback behaviors.
- CoreServiceManager: wrap startContextService calls with try/catch to surface errors to UI; startContextService now throws on invalid state/config and moves startup loop into doStartCoreLoop which registers receivers, starts core loop, and reports detailed failures to UI.
- Show notification when VPN service starts (CoreVpnService) to ensure foreground visibility.
- MainViewModel: display detailed start failure message from intent when available instead of only a generic toast.

These changes improve diagnostics, reduce silent failures, and centralize error handling during startup.

V2rayNG/app/src/main/java/com/v2ray/ang/core/CoreServiceManager.kt

@@ -62,7 +62,13 @@ object CoreServiceManager {
             context.toast(R.string.app_tile_first_use)
             return false
         }
-        startContextService(context)
+        try {
+            startContextService(context)
+        } catch (e: Exception) {
+            LogUtil.e(AppConfig.TAG, "StartCore-Manager: ${e.message}", e)
+            context.toast(e.message ?: e.javaClass.simpleName)
+            return false
+        }
         return true
     }
 
@@ -78,7 +84,12 @@ object CoreServiceManager {
             MmkvManager.setSelectServer(guid)
         }
 
-        startContextService(context)
+        try {
+            startContextService(context)
+        } catch (e: Exception) {
+            LogUtil.e(AppConfig.TAG, "StartCore-Manager: ${e.message}", e)
+            context.toast(e.message ?: e.javaClass.simpleName)
+        }
     }
 
     /**
@@ -106,7 +117,11 @@ object CoreServiceManager {
      * Starts the context service for V2Ray.
      * Chooses between VPN service or Proxy-only service based on user settings.
      * @param context The context from which the service is started.
+     * @throws IllegalStateException if the core is already running, no server is selected,
+     *   server config cannot be decoded, or server configuration is invalid.
+     * @throws Exception if the foreground service fails to start.
      */
+    @Throws(Exception::class)
     private fun startContextService(context: Context) {
         if (coreController.isRunning) {
             LogUtil.w(AppConfig.TAG, "StartCore-Manager: Core already running")
@@ -114,16 +129,16 @@ object CoreServiceManager {
         }
 
         val guid = MmkvManager.getSelectServer()
-        if (guid == null) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: No server selected")
-            return
-        }
+            ?: run {
+                LogUtil.e(AppConfig.TAG, "StartCore-Manager: No server selected")
+                error(context.getString(R.string.app_tile_first_use))
+            }
 
         val config = MmkvManager.decodeServerConfig(guid)
-        if (config == null) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to decode server config")
-            return
-        }
+            ?: run {
+                LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to decode server config")
+                error(context.getString(R.string.toast_config_file_invalid))
+            }
 
         if (config.configType != EConfigType.CUSTOM
             && config.configType != EConfigType.POLICYGROUP
@@ -132,13 +147,14 @@ object CoreServiceManager {
             && !Utils.isPureIpAddress(config.server.orEmpty())
         ) {
             LogUtil.e(AppConfig.TAG, "StartCore-Manager: Invalid server configuration")
-            return
+            error(context.getString(R.string.toast_config_file_invalid))
         }
+
         // refresh socks port when enabled dynamic socks port
         SettingsManager.refreshRuntimeSocksPort()
 
 //        val result = V2rayConfigUtil.getV2rayConfig(context, guid)
-//        if (!result.status) return
+//        if (!result.status) error(result.errorMessage.ifBlank { "Failed to get V2Ray config" })
 
         if (MmkvManager.decodeSettingsBool(AppConfig.PREF_PROXY_SHARING)) {
             context.toast(R.string.toast_warning_pref_proxysharing_short)
@@ -155,11 +171,7 @@ object CoreServiceManager {
             Intent(context.applicationContext, CoreProxyOnlyService::class.java)
         }
 
-        try {
-            ContextCompat.startForegroundService(context, intent)
-        } catch (e: Exception) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to start service", e)
-        }
+        ContextCompat.startForegroundService(context, intent)
     }
 
     /**
@@ -179,36 +191,35 @@ object CoreServiceManager {
             return false
         }
 
-        val guid = MmkvManager.getSelectServer()
-        if (guid == null) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: No server selected")
+        try {
+            doStartCoreLoop(service, vpnInterface)
+            return true
+        } catch (e: Exception) {
+            val message = e.message?.takeUnless { it.isBlank() } ?: e.javaClass.simpleName
+            LogUtil.e(AppConfig.TAG, "StartCore-Manager: $message", e)
+            MessageUtil.sendMsg2UI(service, AppConfig.MSG_STATE_START_FAILURE, message)
+            NotificationManager.cancelNotification()
             return false
         }
+    }
 
-        val config = MmkvManager.decodeServerConfig(guid)
-        if (config == null) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to decode server config")
-            return false
-        }
+    @Throws(Exception::class)
+    private fun doStartCoreLoop(service: Service, vpnInterface: ParcelFileDescriptor?) {
+        val guid = MmkvManager.getSelectServer() ?: error("No server selected")
+        val config = MmkvManager.decodeServerConfig(guid) ?: error("Failed to decode server config")
 
         LogUtil.i(AppConfig.TAG, "StartCore-Manager: Starting core loop for ${config.remarks}")
         val result = CoreConfigManager.getV2rayConfig(service, guid)
         LogUtil.d(AppConfig.TAG, result.content)
         if (!result.status) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to get V2Ray config")
-            return false
+            error(result.errorMessage.ifBlank { "Failed to get V2Ray config" })
         }
 
-        try {
-            val mFilter = IntentFilter(AppConfig.BROADCAST_ACTION_SERVICE)
-            mFilter.addAction(Intent.ACTION_SCREEN_ON)
-            mFilter.addAction(Intent.ACTION_SCREEN_OFF)
-            mFilter.addAction(Intent.ACTION_USER_PRESENT)
-            ContextCompat.registerReceiver(service, mMsgReceive, mFilter, Utils.receiverFlags())
-        } catch (e: Exception) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to register receiver", e)
-            return false
-        }
+        val mFilter = IntentFilter(AppConfig.BROADCAST_ACTION_SERVICE)
+        mFilter.addAction(Intent.ACTION_SCREEN_ON)
+        mFilter.addAction(Intent.ACTION_SCREEN_OFF)
+        mFilter.addAction(Intent.ACTION_USER_PRESENT)
+        ContextCompat.registerReceiver(service, mMsgReceive, mFilter, Utils.receiverFlags())
 
         currentConfig = config
         var tunFd = vpnInterface?.fd ?: 0
@@ -216,30 +227,16 @@ object CoreServiceManager {
             tunFd = 0
         }
 
-        try {
-            NotificationManager.showNotification(currentConfig)
-            coreController.startLoop(result.content, tunFd)
-        } catch (e: Exception) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to start core loop", e)
-            return false
+        NotificationManager.showNotification(currentConfig)
+        coreController.startLoop(result.content, tunFd)
+
+        if (!coreController.isRunning) {
+            error("Core failed to start")
         }
 
-        if (coreController.isRunning == false) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Core failed to start")
-            MessageUtil.sendMsg2UI(service, AppConfig.MSG_STATE_START_FAILURE, "")
-            NotificationManager.cancelNotification()
-            return false
-        }
-
-        try {
-            MessageUtil.sendMsg2UI(service, AppConfig.MSG_STATE_START_SUCCESS, "")
-            NotificationManager.startSpeedNotification(currentConfig)
-            LogUtil.i(AppConfig.TAG, "StartCore-Manager: Core started successfully")
-        } catch (e: Exception) {
-            LogUtil.e(AppConfig.TAG, "StartCore-Manager: Failed to complete startup", e)
-            return false
-        }
-        return true
+        MessageUtil.sendMsg2UI(service, AppConfig.MSG_STATE_START_SUCCESS, "")
+        NotificationManager.startSpeedNotification(currentConfig)
+        LogUtil.i(AppConfig.TAG, "StartCore-Manager: Core started successfully")
     }
 
     /**
@@ -406,7 +403,7 @@ object CoreServiceManager {
                 //LogUtil.d(AppConfig.TAG, "ProcessFinder: Find $network connection from $srcIP:$srcPort to $destIP:$destPort, uid=$uid,${PackageUidResolver.uidToPackageName(uid.toString())}")
 
                 uid
-            } catch (e: Exception) {
+            } catch (_: Exception) {
                 -1L
             }
         }

V2rayNG/app/src/main/java/com/v2ray/ang/dto/ConfigResult.kt

@@ -4,5 +4,6 @@ data class ConfigResult(
     var status: Boolean,
     var guid: String? = null,
     var content: String = "",
+    var errorMessage: String = "",
 )
 

V2rayNG/app/src/main/java/com/v2ray/ang/service/CoreVpnService.kt

@@ -113,6 +113,7 @@ class CoreVpnService : VpnService(), ServiceControl {
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
         LogUtil.i(AppConfig.TAG, "StartCore-VPN: Service command received")
+        NotificationManager.showNotification(null)
         setupVpnService()
         startService()
         return START_STICKY

V2rayNG/app/src/main/java/com/v2ray/ang/viewmodel/MainViewModel.kt

@@ -457,7 +457,12 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
                 }
 
                 AppConfig.MSG_STATE_START_FAILURE -> {
-                    getApplication<AngApplication>().toastError(R.string.toast_services_failure)
+                    val errorMessage = intent.getStringExtra("content")
+                    if (!errorMessage.isNullOrBlank()) {
+                        getApplication<AngApplication>().toastError(errorMessage)
+                    } else {
+                        getApplication<AngApplication>().toastError(R.string.toast_services_failure)
+                    }
                     isRunning.value = false
                 }