Add an iOS withDangerousMod to the Expo config plugin that patches RCTThirdPartyComponentsProvider.mm

[Th0mYT]

What was changed: plugin/src/index.ts (and its compiled output plugin/build/index.js)

What was broken: Expo's prebuild ran the C++ codegen for unityview but never generated the Fabric registration step. RNUnityViewCls() was defined in RNUnityView.mm but never
called, so Fabric couldn't find the component by name, fell back to the legacy interop layer, and updateProps was never dispatched.

The fix — withIosFabricRegistration: A new iOS withDangerousMod that runs at the end of every npx expo prebuild and patches RCTThirdPartyComponentsProvider.mm with two insertions:

// 1. Forward declaration (before @implementation)
Class RNUnityViewCls(void);

// 2. Dictionary entry (inside thirdPartyFabricComponents)
@"RNUnityView" : RNUnityViewCls(),

Call chain after the fix (matches what should happen):
codegenNativeComponent('RNUnityView')
→ Fabric finds RNUnityView via RCTThirdPartyComponentsProvider
→ initWithFrame: (lambda set, initUnityModule called as belt-and-suspenders)
→ updateEventEmitter:
→ updateProps: ← initUnityModule() ← Unity starts ✓

The initUnityModule call in initWithFrame: from the previous commit remains — it acts as a safety net for any edge case where updateProps might still be delayed.

[azesmway]

@Th0mYT Thanks for the improvements!
Can I take a look at everything and publish it?

[Th0mYT]

Can I take a look at everything and publish it?

@azesmway of course. If you want, I'm working on the fork to further optimize the package for both Android and iOS. I'm also updating the plugin for expo. If you want, after finishing these changes and testing everything I can create a new PR with these changes.

[azesmway]

Can I take a look at everything and publish it?

@azesmway of course. If you want, I'm working on the fork to further optimize the package for both Android and iOS. I'm also updating the plugin for expo. If you want, after finishing these changes and testing everything I can create a new PR with these changes.

ok

[Th0mYT]

Can I take a look at everything and publish it?

@azesmway of course. If you want, I'm working on the fork to further optimize the package for both Android and iOS. I'm also updating the plugin for expo. If you want, after finishing these changes and testing everything I can create a new PR with these changes.

ok

I updated the PR.

Summary of changes

ios/RNUnityView.mm — New Architecture fix

• Unity is now initialized immediately inside initWithFrame: without waiting for updateProps to be called.
  This fixes a regression on New Arch where the Unity view would remain blank if no props were passed on mount.

android/.../UPlayer.java — Type cast fix

• Fixed an unsafe cast that caused a compilation warning/error on some setups:
  return unityPlayer → return (FrameLayout)(Object) unityPlayer

plugin/src/index.ts — Expo config plugin refactor

Several issues fixed to make the plugin safe to run multiple times (e.g. after repeated npx expo prebuild):

• withProjectBuildGradleMod: now strips existing flatDir / unityLibrary entries before re-inserting, preventing duplicate lines on every prebuild.
• withSettingsGradleMod: same approach — filters out any existing unityLibrary lines before appending, so the include is always present exactly once.
• withGradlePropertiesMod: checks if unityStreamingAssets property already exists before pushing it, avoiding duplicate gradle properties.
• withStringsXMLMod: renamed internal variable from config to modConfig to avoid shadowing the outer config parameter.
• withAndroidManifestMod (new): adds xmlns:tools to the manifest root and sets tools:replace="android:enableOnBackInvokedCallback" on the tag. This resolves a manifest merger conflict that occurs because unityLibrary declares this attribute with a different value.
• withIosFabricRegistration (new): patches RCTThirdPartyComponentsProvider.mm (generated by expo prebuild) to register RNUnityView with Fabric's component registry. Without this, updateProps is never dispatched on New Arch iOS. The patch is idempotent and skips gracefully if the file doesn't exist yet.
• Removed the unused name option from the plugin config signature.

tsconfig.json — Plugin path alias

• Added @azesmway/react-native-unity/plugin → ./plugin/src/index to the path aliases so the plugin source can be resolved correctly during development.

package.json — Build setup for the plugin

• Added app.plugin.js and plugin/build to the files array so the compiled plugin is included when the package is published.
• Added build:plugin script: tsc --project plugin/tsconfig.json
• Updated prepare to also run build:plugin after bob build.
• Updated clean to also wipe plugin/build.

[Th0mYT]

Hi @azesmway!

I've updated the PR with several improvements focused on stability and Android compatibility.
Here's a summary of what was addressed:

Android surface & rendering fixes

• Fixed black screens after re-parenting the Unity view by improving surface handling
• Added a timeout fallback and measurement adjustments to surface initialization
• Unity rendering is now paused before surface destruction to prevent crashes
• Improved resume timing to ensure the rendering surface is ready before Unity restarts

New Architecture (Fabric) compatibility

• Fixed layout handling and event dispatch for the new React Native architecture
• Force layout pass to ensure valid dimensions in Fabric mode
• Thread safety improvements for Unity callbacks and event dispatch

Android API 30+ compatibility

• Updated UnityPlayer instantiation and flag handling for API 30+
• Disabled predictive back gesture to prevent crashes on older devices
• Wrapped getSurfaceId in try-catch for safer handling

Other

• Removed jcenter() (shut down) from repositories block
• Expo compatibility improvements for iOS Unity framework integration

Happy to discuss any of the changes or provide more context if needed!