fix: render the editor in the locale's text direction

android/app/src/main/AndroidManifest.xml

@@ -10,6 +10,7 @@
         android:fullBackupContent="@xml/backup_rules"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
+        android:localeConfig="@xml/locales_config"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.GutenbergKit"

android/app/src/main/java/com/example/gutenbergkit/DemoAppLocale.kt

@@ -0,0 +1,50 @@
+package com.example.gutenbergkit
+
+import android.app.LocaleManager
+import android.content.Context
+import android.os.Build
+import java.util.Locale
+
+/**
+ * Reads the language the demo app is running in, so the editor can be told
+ * which translations to load.
+ *
+ * The language is chosen through the system's per-app language picker
+ * (Settings > Apps > GutenbergKit > Language), which offers the locales
+ * declared in `res/xml/locales_config.xml`. Forwarding it to
+ * `EditorConfiguration` lets the editor's localization — including
+ * right-to-left rendering — be exercised without code changes.
+ *
+ * Unlike the iOS demo app, no resolution logic lives here:
+ * `EditorConfiguration.Builder.setLocale(Locale)` already resolves against the
+ * bundled translations via the library's `LocaleResolver`.
+ */
+object DemoAppLocale {
+
+    /**
+     * The locale to hand the editor.
+     *
+     * Reads the platform's [LocaleManager] directly rather than going through
+     * `AppCompatDelegate.getApplicationLocales()`. That helper resolves the
+     * application locale by walking appcompat's registry of live activity
+     * delegates, and every activity in this app extends `ComponentActivity`
+     * rather than `AppCompatActivity`, so the registry is always empty and the
+     * helper reports no selection regardless of what the system holds.
+     *
+     * Falls back to the device language when no per-app language is set, or on
+     * Android versions predating per-app languages (API < 33).
+     */
+    fun current(context: Context): Locale {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
+            return Locale.getDefault()
+        }
+
+        val locales = context.getSystemService(LocaleManager::class.java)
+            ?.applicationLocales
+
+        if (locales == null || locales.isEmpty) {
+            return Locale.getDefault()
+        }
+        return locales[0]
+    }
+}

android/app/src/main/java/com/example/gutenbergkit/SitePreparationActivity.kt

@@ -2,11 +2,15 @@ package com.example.gutenbergkit
 
 import android.content.Context
 import android.content.Intent
+import android.net.Uri
+import android.os.Build
 import android.os.Bundle
+import android.provider.Settings
 import org.json.JSONObject
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -43,17 +47,26 @@ import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.unit.dp
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.compose.LocalLifecycleOwner
 import com.example.gutenbergkit.ui.theme.AppTheme
+import java.util.Locale
 import org.wordpress.gutenberg.model.EditorConfiguration
 import org.wordpress.gutenberg.model.EditorDependencies
 import org.wordpress.gutenberg.model.EditorDependenciesSerializer
@@ -203,7 +216,11 @@ fun SitePreparationScreen(
 ) {
     val uiState by viewModel.uiState.collectAsState()
 
-    LaunchedEffect(Unit) {
+    // Re-read on resume so returning from the system language picker is
+    // noticed.
+    val locale = rememberLocaleOnResume()
+
+    LaunchedEffect(locale) {
         viewModel.startLoading()
     }
 
@@ -515,8 +532,85 @@ private fun EditorConfigurationDetailsCard(configuration: EditorConfiguration) {
             KeyValueRow(key = "API Root", value = configuration.siteApiRoot)
             KeyValueBooleanRow(key = "Supports Block Assets", value = configuration.plugins)
             KeyValueBooleanRow(key = "Supports Theme Styles", value = configuration.themeStyles)
+            EditorLocaleRow(locale = configuration.locale)
+        }
+    }
+}
+
+/**
+ * The app's current locale, re-read every time the activity resumes.
+ *
+ * Returning from the system language picker does not reliably recreate this
+ * activity — the picker belongs to another task, so this one is often just
+ * stopped and resumed — and a plain read during composition would never see
+ * the new value. Observing `ON_RESUME` covers both cases.
+ */
+@Composable
+private fun rememberLocaleOnResume(): Locale {
+    val context = LocalContext.current
+    val lifecycleOwner = LocalLifecycleOwner.current
+    var locale by remember { mutableStateOf(DemoAppLocale.current(context)) }
+
+    DisposableEffect(lifecycleOwner) {
+        val observer = LifecycleEventObserver { _, event ->
+            if (event == Lifecycle.Event.ON_RESUME) {
+                locale = DemoAppLocale.current(context)
+            }
+        }
+        lifecycleOwner.lifecycle.addObserver(observer)
+        onDispose { lifecycleOwner.lifecycle.removeObserver(observer) }
+    }
+
+    return locale
+}
+
+/**
+ * Shows the locale the editor will use, linking to the system's per-app
+ * language picker where one exists.
+ *
+ * The value is what the library resolved the app's language to, not the
+ * language itself — a locale with no bundled translations resolves to `en`,
+ * which is otherwise indistinguishable from the selection being ignored.
+ */
+@Composable
+private fun EditorLocaleRow(locale: String?) {
+    val context = LocalContext.current
+    val resolved = locale ?: "en"
+
+    // The action is optional even on API 33+ — some devices ship no handler for
+    // it — so resolve the intent rather than inferring availability from the SDK
+    // level, which would throw on tap.
+    val settingsIntent = remember(context) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
+            null
+        } else {
+            Intent(
+                Settings.ACTION_APP_LOCALE_SETTINGS,
+                Uri.fromParts("package", context.packageName, null)
+            ).takeIf { it.resolveActivity(context.packageManager) != null }
         }
     }
+
+    if (settingsIntent == null) {
+        KeyValueRow(key = "Editor Locale", value = resolved)
+        return
+    }
+
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clickable { context.startActivity(settingsIntent) }
+            .padding(vertical = 4.dp),
+        horizontalArrangement = Arrangement.SpaceBetween,
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        KeyValueRow(key = "Editor Locale", value = resolved)
+        Text(
+            text = "Change",
+            style = MaterialTheme.typography.labelLarge,
+            color = MaterialTheme.colorScheme.primary
+        )
+    }
 }
 
 @Composable

android/app/src/main/java/com/example/gutenbergkit/SitePreparationViewModel.kt

@@ -224,6 +224,7 @@ class SitePreparationViewModel(
             .setAuthHeader("")
             .setCookies(emptyMap())
             .setEnableOfflineMode(true)
+            .setLocale(DemoAppLocale.current(getApplication()))
             .build()
     }
 
@@ -278,6 +279,7 @@ class SitePreparationViewModel(
             .setCookies(emptyMap())
             .setEnableNetworkLogging(true)
             .setEnableAssetCaching(capabilities.supportsPlugins)
+            .setLocale(DemoAppLocale.current(getApplication()))
             .build()
     }
 

android/app/src/main/res/xml/locales_config.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Languages offered by the system's per-app language picker
+    (Settings > Apps > GutenbergKit > Language).
+
+    This is a deliberately curated subset of the ~49 locales the editor ships
+    translations for, chosen so each entry exercises a distinct rendering path:
+
+      en     left-to-right baseline
+      es/fr  Latin translations, accented characters
+      ar     right-to-left, cursive script with contextual letter shaping
+      he     right-to-left, non-cursive — catches shaping bugs `ar` alone hides
+      ja     CJK: Han glyph selection driven by `lang`, wide glyphs, different
+             line-breaking rules
+      pt-BR  the only regional bundle here, so it exercises the library
+             resolver's `language-region` step rather than the bare-language
+             fallback
+
+    Add entries as needed; anything listed must have a matching
+    `src/translations/<tag>.json` or the editor silently falls back to English.
+
+    Only read on Android 13 (API 33) and above. Older versions ignore this file
+    and the app's language follows the device.
+-->
+<locale-config xmlns:android="http://schemas.android.com/apk/res/android">
+    <locale android:name="en" />
+    <locale android:name="es" />
+    <locale android:name="fr" />
+    <locale android:name="ar" />
+    <locale android:name="he" />
+    <locale android:name="ja" />
+    <locale android:name="pt-BR" />
+</locale-config>

ios/Demo-iOS/Gutenberg.xcodeproj/project.pbxproj

@@ -15,6 +15,7 @@
 		246852562EAABB7800ED1F09 /* WordPressAPI in Frameworks */ = {isa = PBXBuildFile; productRef = 0C4F59A12BEFF4980028BD96 /* WordPressAPI */; };
 		2468526B2EAACCA100ED1F09 /* AuthenticationManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 246852682EAACCA100ED1F09 /* AuthenticationManager.swift */; };
 		2468526C2EAACCA100ED1F09 /* ConfigurationStorage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 246852692EAACCA100ED1F09 /* ConfigurationStorage.swift */; };
+		2FCF7A593017EC80008F5560 /* DemoAppLocale.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2FCF7A503017EC80008F5560 /* DemoAppLocale.swift */; };
 		BB0000012F11000000000001 /* GutenbergKitHTTP in Frameworks */ = {isa = PBXBuildFile; productRef = BB0000012F11000000000002 /* GutenbergKitHTTP */; };
 /* End PBXBuildFile section */
 
@@ -36,6 +37,7 @@
 		0CE8E7892C339B0600B9DC67 /* Preview Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = "Preview Assets.xcassets"; sourceTree = "<group>"; };
 		246852682EAACCA100ED1F09 /* AuthenticationManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AuthenticationManager.swift; sourceTree = "<group>"; };
 		246852692EAACCA100ED1F09 /* ConfigurationStorage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConfigurationStorage.swift; sourceTree = "<group>"; };
+		2FCF7A503017EC80008F5560 /* DemoAppLocale.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DemoAppLocale.swift; sourceTree = "<group>"; };
 		AA0000012F00000000000001 /* GutenbergUITests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = GutenbergUITests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
 
@@ -124,6 +126,7 @@
 			isa = PBXGroup;
 			children = (
 				246852682EAACCA100ED1F09 /* AuthenticationManager.swift */,
+				2FCF7A503017EC80008F5560 /* DemoAppLocale.swift */,
 				246852692EAACCA100ED1F09 /* ConfigurationStorage.swift */,
 			);
 			path = Services;
@@ -272,6 +275,7 @@
 				0C4F59A62BEFF4980028BD96 /* ConfigurationItem.swift in Sources */,
 				0CE8E78E2C339B0600B9DC67 /* GutenbergApp.swift in Sources */,
 				2468526B2EAACCA100ED1F09 /* AuthenticationManager.swift in Sources */,
+				2FCF7A593017EC80008F5560 /* DemoAppLocale.swift in Sources */,
 				2468526C2EAACCA100ED1F09 /* ConfigurationStorage.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;