Refactor BaseStoryScreenshotTest to use single activity

packages/rn-storybook-auto-screenshots/android/src/main/java/com/rnstorybookautoscreenshots/BaseStoryRendererActivity.kt

@@ -3,6 +3,7 @@ package com.rnstorybookautoscreenshots
 import android.os.Bundle
 import com.facebook.react.ReactActivity
 import com.facebook.react.ReactActivityDelegate
+import com.facebook.react.ReactApplication
 import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.fabricEnabled
 import com.facebook.react.defaults.DefaultReactActivityDelegate
 
@@ -32,6 +33,12 @@ open class BaseStoryRendererActivity : ReactActivity() {
     /**
      * Returns the instance of the ReactActivityDelegate with custom launch options.
      */
+    fun loadStory(storyName: String) {
+        (application as? ReactApplication)?.reactHost?.currentReactContext
+            ?.getNativeModule(StorybookRegistry::class.java)
+            ?.loadStory(storyName)
+    }
+
     override fun createReactActivityDelegate(): ReactActivityDelegate {
         return object : DefaultReactActivityDelegate(this, mainComponentName, fabricEnabled) {
             override fun getLaunchOptions(): Bundle? {

packages/rn-storybook-auto-screenshots/android/src/main/java/com/rnstorybookautoscreenshots/BaseStoryScreenshotTest.kt

@@ -3,14 +3,18 @@ package com.rnstorybookautoscreenshots
 import android.Manifest
 import android.content.Intent
 import android.util.Log
+import android.view.ViewTreeObserver
 import androidx.test.core.app.ActivityScenario
 import androidx.test.core.app.ApplicationProvider
+import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.GrantPermissionRule
 import com.facebook.testing.screenshot.Screenshot
 import org.junit.Assert.assertTrue
 import org.junit.Rule
 import org.junit.Test
 import java.io.File
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 /**
  * Base screenshot test that automatically discovers and tests all Storybook stories.
@@ -85,36 +89,58 @@ abstract class BaseStoryScreenshotTest {
         val externalDir = context.getExternalFilesDir("screenshots")
         val manifestFile = File(externalDir, StorybookRegistry.STORIES_FILE_NAME)
 
-        // Bootstrap manifest if it doesn't exist
+        val intent = Intent(
+            ApplicationProvider.getApplicationContext(),
+            getStoryRendererActivityClass()
+        ).apply {
+            putExtra(BaseStoryRendererActivity.EXTRA_STORY_NAME, BOOTSTRAP_STORY_NAME)
+        }
+
+        // Launch once — RN initializes and registers all stories
+        StorybookRegistry.prepareForNextStory()
+        val scenario = ActivityScenario.launch<BaseStoryRendererActivity>(intent)
+        StorybookRegistry.awaitStoryReady(getBootstrapTimeoutMs())
+
         if (!manifestFile.exists()) {
-            Log.d(TAG, "Manifest not found, bootstrapping...")
-            bootstrapManifest(manifestFile)
+            waitForManifestFile(manifestFile)
         }
 
         val allStories = StorybookRegistry.getStoriesFromFile(externalDir!!)
         val stories = allStories.filter { shouldScreenshotStory(it) }
 
         Log.d(TAG, "Found ${allStories.size} stories, ${stories.size} after filtering")
-
         assertTrue("No stories found in manifest", stories.isNotEmpty())
 
-        var successCount = 0
-        var failureCount = 0
         val failures = mutableListOf<String>()
 
         for (story in stories) {
             try {
-                screenshotStory(story)
-                successCount++
+                val storyName = story.toStoryName()
+                Log.d(TAG, "Screenshotting: $storyName (id: ${story.id})")
+
+                StorybookRegistry.prepareForNextStory()
+                scenario.onActivity { activity -> activity.loadStory(storyName) }
+                StorybookRegistry.awaitStoryReady(getLoadTimeoutMs())
+                InstrumentationRegistry.getInstrumentation().waitForIdleSync()
+                waitForNextDraw(scenario)
+
+                scenario.onActivity { activity ->
+                    val screenshotName = story.id.replace("--", "_")
+                    Screenshot.snap(activity.window.decorView.rootView)
+                        .setName(screenshotName)
+                        .record()
+                    Log.d(TAG, "Screenshot captured: $screenshotName")
+                }
             } catch (e: Exception) {
-                failureCount++
                 val errorMsg = "${story.title}/${story.name}: ${e.message}"
                 failures.add(errorMsg)
                 Log.e(TAG, "Failed to screenshot story: $errorMsg", e)
             }
         }
 
-        Log.d(TAG, "Screenshot results: $successCount passed, $failureCount failed")
+        scenario.close()
+
+        Log.d(TAG, "Screenshot results: ${stories.size - failures.size} passed, ${failures.size} failed")
 
         if (failures.isNotEmpty()) {
             Log.e(TAG, "Failed stories:\n${failures.joinToString("\n")}")
@@ -126,61 +152,28 @@ abstract class BaseStoryScreenshotTest {
         )
     }
 
-    private fun screenshotStory(storyInfo: StoryInfo) {
-        val storyName = storyInfo.toStoryName()
-        Log.d(TAG, "Screenshotting: $storyName (id: ${storyInfo.id})")
-
-        val intent = Intent(
-            ApplicationProvider.getApplicationContext(),
-            getStoryRendererActivityClass()
-        ).apply {
-            putExtra(BaseStoryRendererActivity.EXTRA_STORY_NAME, storyName)
-        }
-
-        StorybookRegistry.prepareForNextStory()
-        val scenario = ActivityScenario.launch<BaseStoryRendererActivity>(intent)
-
-        // Wait for JS to signal the story has finished rendering, up to the timeout.
-        StorybookRegistry.awaitStoryReady(getLoadTimeoutMs())
-
-        scenario.onActivity { activity ->
-            val rootView = activity.window.decorView.rootView
-
-            // Use story ID as screenshot name (replace -- with _ for filesystem compatibility)
-            val screenshotName = storyInfo.id.replace("--", "_")
-
-            // Capture screenshot using screenshot-tests-for-android
-            // In record mode: saves baseline images
-            // In verify mode: compares against baselines
-            Screenshot.snap(rootView)
-                .setName(screenshotName)
-                .record()
-
-            Log.d(TAG, "Screenshot captured: $screenshotName")
-        }
-
-        scenario.close()
-    }
-
     /**
-     * Bootstraps the story manifest by launching StoryRendererActivity.
-     * This allows React Native to initialize and register all stories.
+     * Waits for the next draw pass on the decor view.
+     *
+     * waitForIdleSync() drains the main thread message queue but view drawing
+     * is triggered by VSYNC via Choreographer, not the message queue. This
+     * method waits for an OnDrawListener callback, which fires after the next
+     * frame is actually drawn — ensuring the screenshot captures painted content.
      */
-    private fun bootstrapManifest(manifestFile: File) {
-        Log.d(TAG, "Launching StoryRenderer to generate manifest...")
-
-        val intent = Intent(
-            ApplicationProvider.getApplicationContext(),
-            getStoryRendererActivityClass()
-        ).apply {
-            putExtra(BaseStoryRendererActivity.EXTRA_STORY_NAME, BOOTSTRAP_STORY_NAME)
+    private fun waitForNextDraw(scenario: ActivityScenario<BaseStoryRendererActivity>) {
+        val latch = CountDownLatch(1)
+        scenario.onActivity { activity ->
+            val decorView = activity.window.decorView
+            decorView.viewTreeObserver.addOnDrawListener(object : ViewTreeObserver.OnDrawListener {
+                override fun onDraw() {
+                    latch.countDown()
+                    decorView.post {
+                        decorView.viewTreeObserver.removeOnDrawListener(this)
+                    }
+                }
+            })
         }
-
-        val scenario = ActivityScenario.launch<BaseStoryRendererActivity>(intent)
-        waitForManifestFile(manifestFile)
-        scenario.close()
-
-        Log.d(TAG, "Bootstrap complete")
+        latch.await(2000, TimeUnit.MILLISECONDS)
     }
 
     /**

packages/rn-storybook-auto-screenshots/android/src/main/java/com/rnstorybookautoscreenshots/StorybookRegistry.kt

@@ -10,11 +10,13 @@ import org.json.JSONObject
 import java.io.File
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
+import com.facebook.react.modules.core.DeviceEventManagerModule
 
 /**
  * Native module that receives the story list from Storybook JS side.
  * Stories are written to a file that screenshot tests can read.
  */
+
 class StorybookRegistry(reactContext: ReactApplicationContext) : ReactContextBaseJavaModule(reactContext) {
 
     companion object {
@@ -77,6 +79,13 @@ class StorybookRegistry(reactContext: ReactApplicationContext) : ReactContextBas
         storyReadyLatch?.countDown()
     }
 
+    fun loadStory(storyName: String) {
+        reactApplicationContext
+            .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter::class.java)
+            ?.emit("loadStory", storyName)
+    }
+
+
     /**
      * Called from JS to register the list of available stories.
      * Writes to external files directory for test access.

packages/rn-storybook-auto-screenshots/src/StoryRenderer.tsx

@@ -1,5 +1,5 @@
 import React, { useEffect, useState } from 'react';
-import { View, Text, StyleSheet, NativeModules } from 'react-native';
+import { View, Text, StyleSheet, NativeModules, NativeEventEmitter } from 'react-native';
 import { storyNameToId } from './utils';
 
 const { StorybookRegistry } = NativeModules;
@@ -57,15 +57,28 @@ export function registerStoriesWithNative() {
  * @param storyName - Format: "ComponentName/StoryName" (e.g., "MyFeature/Initial")
  */
 export function StoryRenderer({ storyName = 'MyFeature/Initial' }: StoryRendererProps) {
+  const [currentStoryName, setCurrentStoryName] = useState(storyName);
   const [storyContent, setStoryContent] = useState<React.ReactNode>(null);
   const [error, setError] = useState<string | null>(null);
   const [loading, setLoading] = useState(true);
 
+  useEffect(() => {
+    const emitter = new NativeEventEmitter(NativeModules.StorybookRegistry);
+    const sub = emitter.addListener('loadStory', (name: string) => {
+      setCurrentStoryName(name);
+      setLoading(true);
+    });
+    return () => sub.remove();
+  }, []);
+
   // Notify native when the story has finished rendering (or errored).
-  // This runs after React commits the update, so the native views are up to date.
+  // requestAnimationFrame defers until after the next frame is painted,
+  // ensuring native view mutations are flushed before the screenshot is taken.
   useEffect(() => {
     if (!loading) {
-      StorybookRegistry.notifyStoryReady();
+      requestAnimationFrame(() => {
+        StorybookRegistry.notifyStoryReady();
+      });
     }
   }, [loading]);
 
@@ -83,7 +96,14 @@ export function StoryRenderer({ storyName = 'MyFeature/Initial' }: StoryRenderer
         // doesn't need to wait for createPreparedStoryMapping().
         registerStoriesWithNative();
 
-        const storyId = storyNameToId(storyName);
+        // Bootstrap story has no '/' — its only purpose is to trigger story
+        // registration above. Nothing to render.
+        if (!currentStoryName.includes('/')) {
+          setLoading(false);
+          return;
+        }
+
+        const storyId = storyNameToId(currentStoryName);
 
         // Wait for Storybook to be ready and prepare story mappings
         if (!storybookView._idToPrepared || Object.keys(storybookView._idToPrepared).length === 0) {
@@ -94,7 +114,7 @@ export function StoryRenderer({ storyName = 'MyFeature/Initial' }: StoryRenderer
 
         if (!preparedStory) {
           const availableStories = Object.keys(storybookView._idToPrepared || {}).join(', ');
-          setError(`Story "${storyId}" not found. Available: ${availableStories}`);
+          setError(`Story "${currentStoryName}" (id: ${storyId}) not found. Available: ${availableStories}`);
           setLoading(false);
           return;
         }
@@ -115,7 +135,7 @@ export function StoryRenderer({ storyName = 'MyFeature/Initial' }: StoryRenderer
     }
 
     renderStory();
-  }, [storyName]);
+  }, [currentStoryName]);
 
   if (loading) {
     return (