From 31ec6b09ccb5cd40cb0bb174ccdf25bd8d021a5d Mon Sep 17 00:00:00 2001
From: Hiroshi Horie <548776+hiroshihorie@users.noreply.github.com>
Date: Mon, 2 Mar 2026 21:19:24 +0900
Subject: [PATCH] Fix audio visualizer exception (#1008)

Fix `MissingPluginException` when stopping audio visualizer.
---
 .changes/fix-audio-visualizer-missing-plugin-exception | 1 +
 lib/src/track/audio_visualizer_native.dart             | 6 ++++--
 shared_swift/LiveKitPlugin.swift                       | 1 +
 shared_swift/Visualizer.swift                          | 7 ++++++-
 4 files changed, 12 insertions(+), 3 deletions(-)
 create mode 100644 .changes/fix-audio-visualizer-missing-plugin-exception

diff --git a/.changes/fix-audio-visualizer-missing-plugin-exception b/.changes/fix-audio-visualizer-missing-plugin-exception
new file mode 100644
index 0000000..d0e10a5
--- /dev/null
+++ b/.changes/fix-audio-visualizer-missing-plugin-exception
@@ -0,0 +1 @@
+patch type="fixed" "MissingPluginException when stopping audio visualizer on Android/iOS"
diff --git a/lib/src/track/audio_visualizer_native.dart b/lib/src/track/audio_visualizer_native.dart
index a7ed376..926049c 100644
--- a/lib/src/track/audio_visualizer_native.dart
+++ b/lib/src/track/audio_visualizer_native.dart
@@ -53,11 +53,13 @@ class AudioVisualizerNative extends AudioVisualizer {
       return;
     }
 
-    await Native.stopVisualizer(mediaStreamTrack.id!, visualizerId: visualizerId);
-
+    // Cancel subscription before native stop, otherwise the native
+    // StreamHandler is already removed and cancel throws MissingPluginException.
     await _streamSubscription?.cancel();
     _streamSubscription = null;
     _eventChannel = null;
+
+    await Native.stopVisualizer(mediaStreamTrack.id!, visualizerId: visualizerId);
   }
 }
 
diff --git a/shared_swift/LiveKitPlugin.swift b/shared_swift/LiveKitPlugin.swift
index 8d11d9e..a2d8d86 100644
--- a/shared_swift/LiveKitPlugin.swift
+++ b/shared_swift/LiveKitPlugin.swift
@@ -201,6 +201,7 @@ public class LiveKitPlugin: NSObject, FlutterPlugin {
         }
 
         for processors in audioProcessors.values {
+            processors.visualizers[visualizerId]?.stop()
             processors.visualizers.removeValue(forKey: visualizerId)
         }
 
diff --git a/shared_swift/Visualizer.swift b/shared_swift/Visualizer.swift
index c856ec5..19c6bd9 100644
--- a/shared_swift/Visualizer.swift
+++ b/shared_swift/Visualizer.swift
@@ -69,8 +69,13 @@ public class Visualizer: NSObject, RTCAudioRenderer, FlutterStreamHandler {
         channel?.setStreamHandler(self)
     }
 
-    deinit {
+    public func stop() {
         _track?.remove(audioRenderer: self)
+        channel?.setStreamHandler(nil)
+    }
+
+    deinit {
+        stop()
     }
 
     public func render(pcmBuffer: AVAudioPCMBuffer) {