From d71c970df8b9b6808b5a03d8064bf90e2946dd55 Mon Sep 17 00:00:00 2001
From: Togetic <31132515+Togetic@users.noreply.github.com>
Date: Tue, 1 Sep 2026 19:02:08 +0200
Subject: [PATCH] fix(android): dispatch Rive events on the UI thread

Rive's render thread emitted JS events inline while holding the
state-machine advance lock. With Reanimated in the tree, delivery is
routed through the main thread, so if the main thread was waiting on
that same lock the two threads deadlocked and Android raised an ANR.

Hand each event to the UI thread via UiThreadUtil.runOnUiThread so the
emitting thread never holds the Rive lock across the bridge call.
---
 .../rivereactnative/RiveReactNativeView.kt    | 43 +++++++++++++------
 1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/android/src/main/java/com/rivereactnative/RiveReactNativeView.kt b/android/src/main/java/com/rivereactnative/RiveReactNativeView.kt
index 4078d65d..5158aaa3 100644
--- a/android/src/main/java/com/rivereactnative/RiveReactNativeView.kt
+++ b/android/src/main/java/com/rivereactnative/RiveReactNativeView.kt
@@ -26,6 +26,7 @@ import com.facebook.react.bridge.ReactContext
 import com.facebook.react.bridge.ReadableArray
 import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.bridge.ReadableType
+import com.facebook.react.bridge.UiThreadUtil
 import com.facebook.react.bridge.WritableMap
 import com.facebook.react.modules.core.DeviceEventManagerModule
 import com.facebook.react.modules.core.ExceptionsManagerModule
@@ -219,8 +220,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     data.putString("animationName", animationName)
     data.putBoolean("isStateMachine", isStateMachine)
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.PLAY.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.PLAY.toString(), data)
+    }
   }
 
   fun onPause(animationName: String, isStateMachine: Boolean = false) {
@@ -230,8 +233,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     data.putString("animationName", animationName)
     data.putBoolean("isStateMachine", isStateMachine)
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.PAUSE.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.PAUSE.toString(), data)
+    }
   }
 
   fun onStop(animationName: String, isStateMachine: Boolean = false) {
@@ -241,8 +246,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     data.putString("animationName", animationName)
     data.putBoolean("isStateMachine", isStateMachine)
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.STOP.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.STOP.toString(), data)
+    }
   }
 
   fun onLoopEnd(animationName: String, loopMode: RNLoopMode) {
@@ -252,8 +259,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     data.putString("animationName", animationName)
     data.putString("loopMode", loopMode.toString())
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.LOOP_END.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.LOOP_END.toString(), data)
+    }
   }
 
   fun onStateChanged(stateMachineName: String, stateName: String) {
@@ -262,8 +271,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     data.putString("stateMachineName", stateMachineName)
     data.putString("stateName", stateName)
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.STATE_CHANGED.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.STATE_CHANGED.toString(), data)
+    }
   }
 
   private fun convertHashMapToWritableMap(hashMap: HashMap<String, Any>): WritableMap {
@@ -301,8 +312,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
       "riveEvent", eventProperties
     )
 
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.RIVE_EVENT.toString(), topLevelDict)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.RIVE_EVENT.toString(), topLevelDict)
+    }
   }
 
   fun play(
@@ -1115,8 +1128,10 @@ class RiveReactNativeView(private val context: ThemedReactContext) : FrameLayout
     val data = Arguments.createMap()
     data.putString("type", error.toString())
     data.putString("message", error.message)
-    reactContext.getJSModule(RCTEventEmitter::class.java)
-      .receiveEvent(id, Events.ERROR.toString(), data)
+    UiThreadUtil.runOnUiThread {
+      reactContext.getJSModule(RCTEventEmitter::class.java)
+        .receiveEvent(id, Events.ERROR.toString(), data)
+    }
   }
 
   private fun warnForUnusedAssets() {