Add kiosk lockdown, custom status strip, crash recovery and error screens

- Kiosk mode: scanning AppConfig.KIOSK_BARCODE toggles Android Lock Task
  mode (persisted). As device owner (KioskAdminReceiver) it is a full
  lockdown and the app becomes the persistent home screen; otherwise it
  falls back to screen pinning. "Salir" and Back-to-exit are disabled
  while kiosk mode is on.
- Status strip: app-drawn bar showing only Wi-Fi status and battery
  percentage; system bars stay hidden.
- Renderer crash: onRenderProcessGone replaces the WebView and reloads
  the last URL; repeated crashes show an error screen instead.
- Error screen: per-cause messages (no Wi-Fi with auto-retry on
  reconnect, server unreachable, 5xx, SSL) and an "Ir al inicio"
  button; 4xx pages are left to the site.
- Mixed content is never allowed.
- Admin volume-key hold reduced to 3 seconds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CLAUDE.md

@@ -25,6 +25,9 @@ app/src/main/java/mx/joykoo/scanner/
   NoSoftKeyboardWebView.kt  — IME suppression via null InputConnection
   ScannerIntegration.kt     — Scanner lifecycle interface
   BroadcastScannerIntegration.kt — Intent-output scans → JS injection (React-safe value setter)
+  KioskController.kt        — Lock Task kiosk toggle (persisted); device-owner full lockdown + HOME alias, else screen pinning
+  KioskAdminReceiver.kt     — DeviceAdminReceiver for `dpm set-device-owner`
+  StatusStrip.kt            — App-drawn status strip (Wi-Fi + battery only); system bars stay hidden
 ```
 
 ## Build
@@ -64,17 +67,25 @@ All configurable values are in `AppConfig.kt`:
 - `BACK_PRESS_EXIT_COUNT` / `BACK_PRESS_WINDOW_MS` — back-button exit guard
 - `ADMIN_VOLUME_HOLD_MS` — hold Volume Up + Volume Down this long to open the admin dialog
 - `ADMIN_BARCODE` — scanning this value (Intent mode) opens the admin dialog
+- `KIOSK_BARCODE` — scanning this value (Intent mode) toggles kiosk lockdown
+- `RENDERER_CRASH_LIMIT` / `RENDERER_CRASH_WINDOW_MS` — WebView crash auto-recovery limit
 
 ## Navigation Rules
 
 - URLs on `joykoo.mx` or `smart.joykoo.mx` (and subdomains) load inside the WebView
 - All other URLs are silently blocked
 - Back button goes back in WebView history; 3 rapid presses exits when no history
-- Admin dialog (exit / toggle soft keyboard): hold both volume keys 5 s, or scan `ADMIN_BARCODE`. Volume keys are consumed and never reach the page. No touch gestures — corner taps leaked through to site UI
+- Admin dialog (exit / toggle soft keyboard): hold both volume keys 3 s, or scan `ADMIN_BARCODE`. Volume keys are consumed and never reach the page. No touch gestures — corner taps leaked through to site UI
+
+## Kiosk & Errors
+
+- Kiosk mode (`KioskController`): when on, admin dialog hides "Salir" and Back never exits. Device owner required for real lockdown; the app can't be uninstalled while device owner, so set it only with the release-signed APK.
+- Error overlay: per-cause messages (no Wi-Fi with auto-retry on reconnect, unreachable, 5xx, SSL, repeated renderer crash). 4xx responses are left to the site.
+- Renderer crash (`onRenderProcessGone`): the WebView is replaced and the last URL (tracked via `doUpdateVisitedHistory`) reloaded.
 
 ## Security
 
-- HTTPS only, no cleartext, no SSL error bypass
+- HTTPS only, no cleartext, mixed content never allowed, no SSL error bypass
 - No JavaScript interfaces exposed
 - No file:// or content:// access
 - Network security config enforces system trust anchors only

README.md

@@ -8,8 +8,10 @@ Aplicación nativa de Android que funciona como navegador dedicado de pantalla c
 - **Supresión del teclado virtual** — El teclado en pantalla de Android nunca aparece, mientras que la entrada del escáner de códigos de barras (modo HID/teclado) funciona normalmente
 - **Modo kiosco** — Pantalla siempre encendida, modo inmersivo, navegación restringida al dominio de la empresa
 - **Persistencia de sesión** — Cookies y almacenamiento local persisten entre reinicios de la aplicación
-- **Manejo de errores de red** — Pantalla de reintento cuando no hay conexión Wi-Fi
+- **Manejo de errores** — Mensajes distintos para sin Wi-Fi (recarga automática al reconectar), servidor sin respuesta, error del servidor (5xx) y certificado inválido; recuperación automática si el motor de la página se cierra
-- **Salida protegida** — Se requieren 3 pulsaciones rápidas del botón Atrás para salir; menú de administrador (salir / mostrar u ocultar teclado) al mantener presionados Subir y Bajar volumen 5 segundos, o al escanear el código de administrador
+- **Barra de estado propia** — Solo muestra Wi-Fi (intensidad / sin internet) y porcentaje de batería
+- **Modo kiosco (bloqueo)** — Se activa/desactiva escaneando el código de kiosco (ver abajo)
+- **Salida protegida** — Se requieren 3 pulsaciones rápidas del botón Atrás para salir; menú de administrador (salir / mostrar u ocultar teclado) al mantener presionados Subir y Bajar volumen 3 segundos, o al escanear el código de administrador
 
 ## Requisitos
 
@@ -54,7 +56,8 @@ Todos los valores configurables están en un solo archivo:
 | `HOME_URL` | URL que se carga al iniciar | `https://smart.joykoo.mx/` |
 | `ALLOWED_HOSTS` | Dominios permitidos dentro del WebView | `smart.joykoo.mx`, `joykoo.mx` |
 | `BACK_PRESS_EXIT_COUNT` | Pulsaciones rápidas de Atrás para salir | 3 |
-| `ADMIN_VOLUME_HOLD_MS` | Tiempo (ms) con ambos botones de volumen presionados para abrir el menú de administrador | 5000 |
+| `ADMIN_VOLUME_HOLD_MS` | Tiempo (ms) con ambos botones de volumen presionados para abrir el menú de administrador | 3000 |
+| `KIOSK_BARCODE` | Código que, al escanearse (modo Intent), activa/desactiva el modo kiosco | `JOYKOO-KIOSK-…` |
 | `ADMIN_BARCODE` | Código que, al escanearse (modo Intent), abre el menú de administrador | `JOYKOO-ADMIN-…` |
 
 ## Uso del escáner
@@ -65,6 +68,22 @@ Todos los valores configurables están en un solo archivo:
 4. El texto escaneado aparece en el campo
 5. Si el escáner envía Enter al final, la página lo procesa normalmente
 
+## Modo kiosco
+
+Escanear `KIOSK_BARCODE` activa o desactiva el bloqueo (Lock Task de Android). El estado se guarda y se vuelve a aplicar al abrir la app. Mientras está activo, el menú de administrador no ofrece "Salir" y el botón Atrás no cierra la app.
+
+Para un bloqueo completo (sin botones Inicio/Recientes, sin panel de notificaciones, sin aviso del sistema y regreso automático a la app tras reiniciar), la app debe ser **propietaria del dispositivo** (*device owner*). En un dispositivo recién restablecido y **sin cuentas** (Google, etc.):
+
+```bash
+adb install app-release.apk
+adb shell dpm set-device-owner mx.joykoo.scanner/.KioskAdminReceiver
+```
+
+Importante:
+- Instale el APK **firmado de producción** antes de este paso. Una app propietaria no se puede desinstalar (solo con restablecimiento de fábrica), así que no se podrá cambiar a un APK firmado con otra clave.
+- Sin *device owner*, el modo kiosco usa la "fijación de pantalla" de Android: el sistema pide confirmación y el usuario puede salir manteniendo Atrás + Recientes.
+- Desactive el atajo de accesibilidad de volumen (Ajustes → Accesibilidad) para que mantener ambos botones de volumen no active TalkBack.
+
 ## Estructura del proyecto
 
 ```
@@ -73,7 +92,10 @@ app/src/main/java/mx/joykoo/scanner/
 ├── MainActivity.kt           — Actividad principal (kiosco, WebView, navegación)
 ├── NoSoftKeyboardWebView.kt  — WebView que suprime el teclado virtual
 ├── ScannerIntegration.kt     — Interfaz para integración con el escáner
-└── BroadcastScannerIntegration.kt — Recepción de códigos en modo Intent
+├── BroadcastScannerIntegration.kt — Recepción de códigos en modo Intent
+├── KioskController.kt        — Modo kiosco (Lock Task, pantalla de inicio)
+├── KioskAdminReceiver.kt     — Componente de propietario del dispositivo
+└── StatusStrip.kt            — Barra de estado propia (Wi-Fi y batería)
 ```
 
 ## Modo de salida por Intent (broadcast)

app/src/main/AndroidManifest.xml

@@ -3,6 +3,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
 
     <application
         android:allowBackup="true"
@@ -37,6 +38,34 @@
             </intent-filter>
         </activity>
 
+        <!-- Home-screen entry, enabled only while kiosk mode is on (KioskController)
+             so the app returns after a reboot instead of the normal launcher. -->
+        <activity-alias
+            android:name=".KioskHome"
+            android:enabled="false"
+            android:exported="true"
+            android:targetActivity=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.HOME" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </activity-alias>
+
+        <!-- Device owner component for full Lock Task kiosk mode:
+             adb shell dpm set-device-owner mx.joykoo.scanner/.KioskAdminReceiver -->
+        <receiver
+            android:name=".KioskAdminReceiver"
+            android:exported="true"
+            android:permission="android.permission.BIND_DEVICE_ADMIN">
+            <meta-data
+                android:name="android.app.device_admin"
+                android:resource="@xml/device_admin" />
+            <intent-filter>
+                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
+            </intent-filter>
+        </receiver>
+
     </application>
 
 </manifest>

app/src/main/java/mx/joykoo/scanner/AppConfig.kt

@@ -19,12 +19,21 @@ object AppConfig {
     const val BACK_PRESS_WINDOW_MS = 2000L
 
     /** How long (ms) Volume Up + Volume Down must be held together to open the admin dialog. */
-    const val ADMIN_VOLUME_HOLD_MS = 5000L
+    const val ADMIN_VOLUME_HOLD_MS = 3000L
 
     /** Scanning a barcode with exactly this value opens the admin dialog instead of
      *  being typed into the page (Intent output mode only). Print it as a QR/Code128. */
     const val ADMIN_BARCODE = "JOYKOO-ADMIN-O4306IFH9AUJ"
 
+    /** Scanning this value toggles kiosk lockdown (Lock Task mode) on/off. Intent output
+     *  mode only. Full lockdown needs the app set as device owner — see README. */
+    const val KIOSK_BARCODE = "JOYKOO-KIOSK-8PRMVBA5WSL5"
+
+    /** WebView renderer crashes allowed within RENDERER_CRASH_WINDOW_MS before the app
+     *  stops auto-reloading and shows the error screen instead. */
+    const val RENDERER_CRASH_LIMIT = 3
+    const val RENDERER_CRASH_WINDOW_MS = 60_000L
+
     /** Broadcast actions sent by scanners in "Intent output" mode (Urovo first, then
      *  other common Chinese vendors). Add the device's action here if it differs. */
     val SCANNER_BROADCAST_ACTIONS = listOf(

app/src/main/java/mx/joykoo/scanner/KioskAdminReceiver.kt

@@ -0,0 +1,11 @@
+package mx.joykoo.scanner
+
+import android.app.admin.DeviceAdminReceiver
+
+/**
+ * Device admin component. Making the app device owner lets KioskController use
+ * full Lock Task mode (no Home/Recents, no notification shade, no prompt):
+ *
+ *   adb shell dpm set-device-owner mx.joykoo.scanner/.KioskAdminReceiver
+ */
+class KioskAdminReceiver : DeviceAdminReceiver()

app/src/main/java/mx/joykoo/scanner/KioskController.kt

@@ -0,0 +1,99 @@
+package mx.joykoo.scanner
+
+import android.app.Activity
+import android.app.ActivityManager
+import android.app.admin.DevicePolicyManager
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.content.pm.PackageManager
+import android.os.Build
+import android.util.Log
+
+/**
+ * Kiosk lockdown via Android Lock Task mode, toggled by scanning AppConfig.KIOSK_BARCODE.
+ * The on/off setting is persisted and re-applied on every resume.
+ *
+ * - Device owner: true lockdown. Home/Recents and the notification shade are blocked,
+ *   only the power menu stays available, and the app becomes the persistent home
+ *   screen so it comes back after a reboot.
+ * - Not device owner: falls back to screen pinning, which shows a system prompt and
+ *   can be undone by the user (hold Back + Recents).
+ */
+class KioskController(private val activity: Activity) {
+
+    private val dpm = activity.getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
+    private val am = activity.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
+    private val admin = ComponentName(activity, KioskAdminReceiver::class.java)
+    private val homeAlias = ComponentName(activity, "${activity.packageName}.KioskHome")
+    private val prefs = activity.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
+
+    val isDeviceOwner: Boolean
+        get() = dpm.isDeviceOwnerApp(activity.packageName)
+
+    var isEnabled: Boolean
+        get() = prefs.getBoolean(KEY_ENABLED, false)
+        private set(value) = prefs.edit().putBoolean(KEY_ENABLED, value).apply()
+
+    private val isInLockTask: Boolean
+        get() = am.lockTaskModeState != ActivityManager.LOCK_TASK_MODE_NONE
+
+    fun toggle(): Boolean {
+        isEnabled = !isEnabled
+        apply()
+        return isEnabled
+    }
+
+    /** Brings the device in line with the saved setting. Call from onResume. */
+    fun apply() {
+        try {
+            if (isEnabled) enter() else exit()
+        } catch (e: Exception) {
+            Log.e(TAG, "Kiosk ${if (isEnabled) "enter" else "exit"} failed", e)
+        }
+    }
+
+    private fun enter() {
+        if (isDeviceOwner) {
+            dpm.setLockTaskPackages(admin, arrayOf(activity.packageName))
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+                dpm.setLockTaskFeatures(admin, DevicePolicyManager.LOCK_TASK_FEATURE_GLOBAL_ACTIONS)
+            }
+            setHomeScreen(true)
+        }
+        if (!isInLockTask) activity.startLockTask()
+    }
+
+    private fun exit() {
+        if (isInLockTask) activity.stopLockTask()
+        if (isDeviceOwner) {
+            setHomeScreen(false)
+            dpm.setLockTaskPackages(admin, emptyArray())
+        }
+    }
+
+    private fun setHomeScreen(enabled: Boolean) {
+        activity.packageManager.setComponentEnabledSetting(
+            homeAlias,
+            if (enabled) PackageManager.COMPONENT_ENABLED_STATE_ENABLED
+            else PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
+            PackageManager.DONT_KILL_APP
+        )
+        if (enabled) {
+            val filter = IntentFilter(Intent.ACTION_MAIN).apply {
+                addCategory(Intent.CATEGORY_HOME)
+                addCategory(Intent.CATEGORY_DEFAULT)
+            }
+            dpm.addPersistentPreferredActivity(admin, filter, homeAlias)
+        } else {
+            dpm.clearPackagePersistentPreferredActivities(admin, activity.packageName)
+        }
+    }
+
+    companion object {
+        private const val TAG = "JoykooScanner"
+        private const val PREFS = "kiosk"
+        private const val KEY_ENABLED = "enabled"
+    }
+}

app/src/main/java/mx/joykoo/scanner/MainActivity.kt

@@ -9,15 +9,20 @@ import android.net.NetworkCapabilities
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.os.SystemClock
 import android.util.Log
 import android.view.KeyEvent
 import android.view.View
+import android.view.ViewGroup
 import android.view.WindowInsets
 import android.view.WindowInsetsController
 import android.view.WindowManager
 import android.view.inputmethod.InputMethodManager
 import android.webkit.ConsoleMessage
 import android.webkit.CookieManager
+import android.webkit.RenderProcessGoneDetail
 import android.webkit.SslErrorHandler
 import android.webkit.ValueCallback
 import android.webkit.WebChromeClient
@@ -27,7 +32,9 @@ import android.webkit.WebResourceResponse
 import android.webkit.WebSettings
 import android.webkit.WebView
 import android.webkit.WebViewClient
+import android.widget.TextView
 import android.widget.Toast
+import androidx.annotation.RequiresApi
 import androidx.activity.OnBackPressedCallback
 import androidx.appcompat.app.AppCompatActivity
 import org.json.JSONObject
@@ -37,8 +44,17 @@ class MainActivity : AppCompatActivity() {
     private lateinit var webView: NoSoftKeyboardWebView
     private lateinit var errorOverlay: View
     private lateinit var scanner: ScannerIntegration
+    private lateinit var kiosk: KioskController
+    private lateinit var statusStrip: StatusStrip
+    private val handler = Handler(Looper.getMainLooper())
     private var fileUploadCallback: ValueCallback<Array<Uri>>? = null
-    private var isShowingError = false
+
+    // Error overlay state: what is shown and which URL Retry should load
+    private var currentError: ErrorKind? = null
+    private val isShowingError get() = currentError != null
+    private var failedUrl: String? = null
+    private var lastLoadedUrl: String? = null
+    private val rendererCrashTimestamps = mutableListOf<Long>()
 
     // Admin dialog: hold Volume Up + Volume Down, or scan AppConfig.ADMIN_BARCODE
     private val volumeKeysDown = mutableSetOf<Int>()
@@ -58,6 +74,13 @@ class MainActivity : AppCompatActivity() {
         setupErrorOverlay()
         setupBackNavigation()
         scanner = BroadcastScannerIntegration(this, ::onBarcodeScanned)
+        kiosk = KioskController(this)
+        statusStrip = StatusStrip(
+            this,
+            findViewById(R.id.status_wifi),
+            findViewById(R.id.status_battery),
+            ::onWifiChanged
+        )
 
         if (savedInstanceState == null) {
             webView.loadUrl(AppConfig.HOME_URL)
@@ -105,13 +128,17 @@ class MainActivity : AppCompatActivity() {
     @SuppressLint("SetJavaScriptEnabled")
     private fun setupWebView() {
         webView = findViewById(R.id.webview)
+        configureWebView()
+    }
 
+    @SuppressLint("SetJavaScriptEnabled")
+    private fun configureWebView() {
         webView.settings.apply {
             javaScriptEnabled = true
             domStorageEnabled = true
             databaseEnabled = true
 
-            mixedContentMode = WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE
+            mixedContentMode = WebSettings.MIXED_CONTENT_NEVER_ALLOW
 
             // Cache and storage for session persistence
             cacheMode = WebSettings.LOAD_DEFAULT
@@ -148,28 +175,50 @@ class MainActivity : AppCompatActivity() {
 
     // ── Error Overlay ───────────────────────────────────────────────────
 
+    private enum class ErrorKind(val title: Int, val message: Int) {
+        NO_WIFI(R.string.error_no_wifi_title, R.string.error_no_wifi_message),
+        UNREACHABLE(R.string.error_unreachable_title, R.string.error_unreachable_message),
+        SERVER(R.string.error_server_title, R.string.error_server_message),
+        SSL(R.string.error_ssl_title, R.string.error_ssl_message),
+        RENDERER_CRASH(R.string.error_crash_title, R.string.error_crash_message),
+    }
+
     private fun setupErrorOverlay() {
         errorOverlay = findViewById(R.id.error_overlay)
-        findViewById<View>(R.id.btn_retry).setOnClickListener {
+        findViewById<View>(R.id.btn_retry).setOnClickListener { retryFailedLoad() }
-            hideError()
+        findViewById<View>(R.id.btn_home).setOnClickListener {
-            if (isNetworkAvailable()) {
+            failedUrl = AppConfig.HOME_URL
-                webView.reload()
+            retryFailedLoad()
-            } else {
-                showError()
-            }
         }
     }
 
-    private fun showError() {
+    private fun showError(kind: ErrorKind, url: String?, httpStatus: Int = 0) {
-        isShowingError = true
+        currentError = kind
+        if (url != null) failedUrl = url
+        findViewById<TextView>(R.id.error_title).setText(kind.title)
+        findViewById<TextView>(R.id.error_message).text = getString(kind.message, httpStatus)
         errorOverlay.visibility = View.VISIBLE
     }
 
     private fun hideError() {
-        isShowingError = false
+        currentError = null
         errorOverlay.visibility = View.GONE
     }
 
+    private fun retryFailedLoad() {
+        if (!isNetworkAvailable()) {
+            showError(ErrorKind.NO_WIFI, null)
+            return
+        }
+        hideError()
+        webView.loadUrl(failedUrl ?: AppConfig.HOME_URL)
+    }
+
+    /** Called by the status strip; reloads automatically when Wi-Fi comes back. */
+    private fun onWifiChanged(online: Boolean) {
+        if (online && currentError == ErrorKind.NO_WIFI) retryFailedLoad()
+    }
+
     private fun isNetworkAvailable(): Boolean {
         val cm = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
         val network = cm.activeNetwork ?: return false
@@ -198,6 +247,7 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun handleExitBackPress() {
+        if (kiosk.isEnabled) return
         val now = System.currentTimeMillis()
         backPressTimestamps.add(now)
         backPressTimestamps.removeAll { now - it > AppConfig.BACK_PRESS_WINDOW_MS }
@@ -223,12 +273,12 @@ class MainActivity : AppCompatActivity() {
             KeyEvent.ACTION_DOWN -> if (event.repeatCount == 0) {
                 volumeKeysDown.add(event.keyCode)
                 if (volumeKeysDown.size == 2) {
-                    webView.postDelayed(adminHoldRunnable, AppConfig.ADMIN_VOLUME_HOLD_MS)
+                    handler.postDelayed(adminHoldRunnable, AppConfig.ADMIN_VOLUME_HOLD_MS)
                 }
             }
             KeyEvent.ACTION_UP -> {
                 volumeKeysDown.remove(event.keyCode)
-                webView.removeCallbacks(adminHoldRunnable)
+                handler.removeCallbacks(adminHoldRunnable)
             }
         }
     }
@@ -236,16 +286,31 @@ class MainActivity : AppCompatActivity() {
     private fun showAdminDialog() {
         // The dialog takes focus, so the volume key-ups never reach us.
         volumeKeysDown.clear()
-        webView.removeCallbacks(adminHoldRunnable)
+        handler.removeCallbacks(adminHoldRunnable)
         val keyboardLabel = if (isKeyboardSuppressed)
             getString(R.string.keyboard_show) else getString(R.string.keyboard_hide)
-        AlertDialog.Builder(this)
+        val builder = AlertDialog.Builder(this)
             .setTitle(R.string.admin_title)
-            .setMessage(R.string.admin_message)
-            .setPositiveButton(R.string.admin_exit) { _, _ -> finish() }
             .setNeutralButton(keyboardLabel) { _, _ -> toggleKeyboard() }
             .setNegativeButton(R.string.admin_cancel, null)
-            .show()
+        // Exiting is only offered outside kiosk mode; the kiosk barcode must be scanned first.
+        if (kiosk.isEnabled) {
+            builder.setMessage(R.string.admin_message_kiosk)
+        } else {
+            builder.setMessage(R.string.admin_message)
+                .setPositiveButton(R.string.admin_exit) { _, _ -> finish() }
+        }
+        builder.show()
+    }
+
+    private fun toggleKiosk() {
+        val enabled = kiosk.toggle()
+        val message = when {
+            !enabled -> R.string.kiosk_disabled
+            kiosk.isDeviceOwner -> R.string.kiosk_enabled
+            else -> R.string.kiosk_enabled_pinning
+        }
+        Toast.makeText(this, message, Toast.LENGTH_LONG).show()
     }
 
     private fun toggleKeyboard() {
@@ -268,6 +333,8 @@ class MainActivity : AppCompatActivity() {
         super.onResume()
         webView.onResume()
         scanner.onResume()
+        statusStrip.start()
+        kiosk.apply()
         enterImmersiveMode()
         ensureWebViewFocus()
         CookieManager.getInstance().flush()
@@ -277,6 +344,7 @@ class MainActivity : AppCompatActivity() {
         super.onPause()
         webView.onPause()
         scanner.onPause()
+        statusStrip.stop()
         CookieManager.getInstance().flush()
     }
 
@@ -292,6 +360,7 @@ class MainActivity : AppCompatActivity() {
 
     override fun onDestroy() {
         scanner.onDestroy()
+        handler.removeCallbacksAndMessages(null)
         webView.destroy()
         super.onDestroy()
     }
@@ -325,7 +394,11 @@ class MainActivity : AppCompatActivity() {
     // assigning el.value directly is silently discarded by React.
 
     private fun onBarcodeScanned(text: String) {
-        if (text == AppConfig.ADMIN_BARCODE) showAdminDialog() else injectScannedText(text)
+        when (text) {
+            AppConfig.ADMIN_BARCODE -> showAdminDialog()
+            AppConfig.KIOSK_BARCODE -> toggleKiosk()
+            else -> injectScannedText(text)
+        }
     }
 
     private fun injectScannedText(text: String) {
@@ -427,6 +500,44 @@ class MainActivity : AppCompatActivity() {
         """.trimIndent(), null)
     }
 
+    // ── Renderer Crash Recovery ─────────────────────────────────────────
+    // A dead renderer leaves the WebView unusable, so it is replaced with a new
+    // instance and the last page reloaded. Repeated crashes stop the reload loop
+    // and show the error screen instead.
+
+    private fun recoverFromRendererCrash() {
+        val now = SystemClock.elapsedRealtime()
+        rendererCrashTimestamps.add(now)
+        rendererCrashTimestamps.removeAll { now - it > AppConfig.RENDERER_CRASH_WINDOW_MS }
+
+        val url = lastLoadedUrl ?: AppConfig.HOME_URL
+        replaceWebView()
+
+        if (rendererCrashTimestamps.size >= AppConfig.RENDERER_CRASH_LIMIT) {
+            rendererCrashTimestamps.clear()
+            showError(ErrorKind.RENDERER_CRASH, url)
+        } else {
+            webView.loadUrl(url)
+        }
+    }
+
+    private fun replaceWebView() {
+        val old = webView
+        val parent = old.parent as ViewGroup
+        val index = parent.indexOfChild(old)
+        val params = old.layoutParams
+        parent.removeView(old)
+        old.destroy()
+
+        webView = NoSoftKeyboardWebView(this).apply {
+            id = R.id.webview
+            keyboardSuppressed = isKeyboardSuppressed
+        }
+        parent.addView(webView, index, params)
+        configureWebView()
+        ensureWebViewFocus()
+    }
+
     // ── WebViewClient ───────────────────────────────────────────────────
 
     private inner class ScannerWebViewClient : WebViewClient() {
@@ -449,6 +560,12 @@ class MainActivity : AppCompatActivity() {
             if (isShowingError) hideError()
         }
 
+        // Also fires for client-side (pushState) navigation, unlike onPageFinished.
+        override fun doUpdateVisitedHistory(view: WebView, url: String?, isReload: Boolean) {
+            super.doUpdateVisitedHistory(view, url, isReload)
+            if (url != null && url.startsWith("https://")) lastLoadedUrl = url
+        }
+
         override fun onPageFinished(view: WebView, url: String?) {
             super.onPageFinished(view, url)
             CookieManager.getInstance().flush()
@@ -464,7 +581,14 @@ class MainActivity : AppCompatActivity() {
         ) {
             if (request.isForMainFrame) {
                 Log.e(TAG, "WebView error: ${error.description} (${error.errorCode})")
-                showError()
+                // Keep the more specific message from onReceivedSslError for this load.
+                if (currentError == ErrorKind.SSL) return
+                val kind = when {
+                    error.errorCode == ERROR_FAILED_SSL_HANDSHAKE -> ErrorKind.SSL
+                    !isNetworkAvailable() -> ErrorKind.NO_WIFI
+                    else -> ErrorKind.UNREACHABLE
+                }
+                showError(kind, request.url.toString())
             }
         }
 
@@ -473,9 +597,10 @@ class MainActivity : AppCompatActivity() {
             request: WebResourceRequest,
             errorResponse: WebResourceResponse
         ) {
-            if (request.isForMainFrame) {
+            // 4xx pages (not found, session expired…) are left to the site to render.
+            if (request.isForMainFrame && errorResponse.statusCode >= 500) {
                 Log.e(TAG, "HTTP error ${errorResponse.statusCode} for ${request.url}")
-                showError()
+                showError(ErrorKind.SERVER, request.url.toString(), errorResponse.statusCode)
             }
         }
 
@@ -486,7 +611,15 @@ class MainActivity : AppCompatActivity() {
         ) {
             Log.e(TAG, "SSL error: ${error.primaryError} for ${error.url}")
             handler.cancel()
-            showError()
+            showError(ErrorKind.SSL, error.url)
+        }
+
+        @RequiresApi(Build.VERSION_CODES.O)
+        override fun onRenderProcessGone(view: WebView, detail: RenderProcessGoneDetail): Boolean {
+            Log.e(TAG, "WebView renderer gone (crashed=${detail.didCrash()})")
+            // Recover on the next loop iteration; the dead view must not be touched here.
+            this@MainActivity.handler.post { if (!isFinishing) recoverFromRendererCrash() }
+            return true
         }
     }
 

app/src/main/java/mx/joykoo/scanner/StatusStrip.kt

@@ -0,0 +1,134 @@
+package mx.joykoo.scanner
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.graphics.Color
+import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkCapabilities
+import android.net.NetworkRequest
+import android.net.wifi.WifiManager
+import android.os.BatteryManager
+import android.os.Build
+import android.text.SpannableStringBuilder
+import android.text.style.ForegroundColorSpan
+import android.widget.TextView
+import androidx.core.content.ContextCompat
+
+/**
+ * App-drawn replacement for the system status bar (which stays hidden by immersive
+ * mode): shows only Wi-Fi status and battery percentage.
+ *
+ * [onWifiChanged] is called on the main thread with whether Wi-Fi has working internet.
+ */
+class StatusStrip(
+    private val context: Context,
+    private val wifiText: TextView,
+    private val batteryText: TextView,
+    private val onWifiChanged: (Boolean) -> Unit,
+) {
+    private val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+    private val wifiManager =
+        context.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
+    private var started = false
+
+    private val batteryReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context, intent: Intent) = showBattery(intent)
+    }
+
+    private val wifiCallback = object : ConnectivityManager.NetworkCallback() {
+        override fun onAvailable(network: Network) = post(cm.getNetworkCapabilities(network))
+        override fun onCapabilitiesChanged(network: Network, caps: NetworkCapabilities) = post(caps)
+        override fun onLost(network: Network) = post(null)
+    }
+
+    fun start() {
+        if (started) return
+        started = true
+        showWifi(null)
+        ContextCompat.registerReceiver(
+            context, batteryReceiver, IntentFilter(Intent.ACTION_BATTERY_CHANGED),
+            ContextCompat.RECEIVER_NOT_EXPORTED
+        )
+        val request = NetworkRequest.Builder()
+            .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
+            .build()
+        cm.registerNetworkCallback(request, wifiCallback)
+    }
+
+    fun stop() {
+        if (!started) return
+        started = false
+        context.unregisterReceiver(batteryReceiver)
+        cm.unregisterNetworkCallback(wifiCallback)
+    }
+
+    // Network callbacks arrive on a background thread.
+    private fun post(caps: NetworkCapabilities?) {
+        wifiText.post { if (started) showWifi(caps) }
+    }
+
+    private fun showWifi(caps: NetworkCapabilities?) {
+        if (caps == null) {
+            wifiText.text = context.getString(R.string.status_no_wifi)
+            wifiText.setTextColor(COLOR_ALERT)
+            onWifiChanged(false)
+            return
+        }
+        val online = caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
+        val bars = signalBars(caps)
+        val text = SpannableStringBuilder("Wi-Fi ")
+        BAR_GLYPHS.forEachIndexed { i, glyph ->
+            val start = text.length
+            text.append(glyph)
+            text.setSpan(
+                ForegroundColorSpan(if (i < bars) COLOR_TEXT else COLOR_DIM),
+                start, text.length, 0
+            )
+        }
+        if (!online) text.append("  ").append(context.getString(R.string.status_no_internet))
+        wifiText.text = text
+        wifiText.setTextColor(if (online) COLOR_TEXT else COLOR_WARN)
+        onWifiChanged(online)
+    }
+
+    @Suppress("DEPRECATION")
+    private fun signalBars(caps: NetworkCapabilities): Int {
+        val rssi = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) caps.signalStrength
+                   else wifiManager.connectionInfo.rssi
+        return when {
+            rssi == Int.MIN_VALUE -> 0
+            rssi >= -55 -> 4
+            rssi >= -66 -> 3
+            rssi >= -77 -> 2
+            rssi >= -88 -> 1
+            else -> 0
+        }
+    }
+
+    private fun showBattery(intent: Intent) {
+        val level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1)
+        val scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100)
+        if (level < 0 || scale <= 0) return
+        val percent = level * 100 / scale
+        val status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1)
+        val charging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
+                status == BatteryManager.BATTERY_STATUS_FULL
+        batteryText.text = if (charging)
+            context.getString(R.string.status_battery_charging, percent)
+        else
+            context.getString(R.string.status_battery, percent)
+        batteryText.setTextColor(if (!charging && percent <= LOW_BATTERY) COLOR_ALERT else COLOR_TEXT)
+    }
+
+    companion object {
+        private const val BAR_GLYPHS = "▂▄▆█"
+        private const val LOW_BATTERY = 15
+        private val COLOR_TEXT = Color.WHITE
+        private val COLOR_DIM = Color.parseColor("#6B7280")
+        private val COLOR_WARN = Color.parseColor("#FBBF24")
+        private val COLOR_ALERT = Color.parseColor("#F87171")
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -1,37 +1,74 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <!-- App-drawn status strip: Wi-Fi and battery only (system bars stay hidden) -->
+    <LinearLayout
+        android:id="@+id/status_strip"
+        android:layout_width="match_parent"
+        android:layout_height="24dp"
+        android:background="#1F2937"
+        android:gravity="center_vertical"
+        android:orientation="horizontal"
+        android:paddingHorizontal="12dp">
+
+        <TextView
+            android:id="@+id/status_wifi"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:maxLines="1"
+            android:textColor="#FFFFFF"
+            android:textSize="13sp" />
+
+        <TextView
+            android:id="@+id/status_battery"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:maxLines="1"
+            android:textColor="#FFFFFF"
+            android:textSize="13sp" />
+
+    </LinearLayout>
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1">
 
         <mx.joykoo.scanner.NoSoftKeyboardWebView
             android:id="@+id/webview"
             android:layout_width="match_parent"
             android:layout_height="match_parent" />
 
-    <!-- Error overlay shown when the page cannot load (e.g. no network) -->
+        <!-- Error overlay; title/message are set per error kind in MainActivity -->
         <LinearLayout
             android:id="@+id/error_overlay"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:background="#FFFFFF"
+            android:clickable="true"
+            android:focusable="true"
             android:gravity="center"
             android:orientation="vertical"
             android:padding="32dp"
             android:visibility="gone">
 
             <TextView
+                android:id="@+id/error_title"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-            android:text="@string/error_no_connection"
                 android:textAlignment="center"
                 android:textColor="#333333"
                 android:textSize="18sp" />
 
             <TextView
+                android:id="@+id/error_message"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_marginTop="8dp"
-            android:text="@string/error_check_wifi"
                 android:textAlignment="center"
                 android:textColor="#666666"
                 android:textSize="14sp" />
@@ -44,6 +81,16 @@
                 android:paddingHorizontal="32dp"
                 android:text="@string/retry" />
 
+            <Button
+                android:id="@+id/btn_home"
+                style="?android:attr/borderlessButtonStyle"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:text="@string/go_home" />
+
         </LinearLayout>
 
     </FrameLayout>
+
+</LinearLayout>

app/src/main/res/values/strings.xml

@@ -1,9 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <string name="app_name">Joykoo Scanner</string>
-    <string name="error_no_connection">No se puede conectar</string>
-    <string name="error_check_wifi">Verifique la conexión Wi-Fi e intente de nuevo.</string>
     <string name="retry">Reintentar</string>
+    <string name="go_home">Ir al inicio</string>
+    <string name="error_no_wifi_title">Sin conexión Wi-Fi</string>
+    <string name="error_no_wifi_message">Verifique la conexión Wi-Fi. La página se recargará automáticamente al reconectarse.</string>
+    <string name="error_unreachable_title">No se puede conectar con el servidor</string>
+    <string name="error_unreachable_message">Hay conexión a la red, pero el servidor no responde. Intente de nuevo en unos momentos.</string>
+    <string name="error_server_title">El servidor tuvo un problema</string>
+    <string name="error_server_message">Error %1$d. Intente de nuevo en unos minutos; si continúa, avise a sistemas.</string>
+    <string name="error_ssl_title">Conexión no segura</string>
+    <string name="error_ssl_message">No se pudo verificar el certificado del servidor. Revise que la fecha y hora del dispositivo sean correctas o avise a sistemas.</string>
+    <string name="error_crash_title">La página dejó de funcionar</string>
+    <string name="error_crash_message">La página se cerró inesperadamente varias veces. Toque Reintentar para cargarla de nuevo.</string>
     <string name="admin_title">Administración</string>
     <string name="admin_message">¿Qué desea hacer?</string>
     <string name="admin_exit">Salir</string>
@@ -12,4 +21,12 @@
     <string name="keyboard_hide">Ocultar teclado</string>
     <string name="keyboard_enabled">Teclado en pantalla activado</string>
     <string name="keyboard_disabled">Teclado en pantalla desactivado</string>
+    <string name="admin_message_kiosk">Modo kiosco activo. Para salir, primero desactívelo escaneando el código de kiosco.</string>
+    <string name="kiosk_enabled">Modo kiosco activado</string>
+    <string name="kiosk_enabled_pinning">Modo kiosco activado (fijación de pantalla: el dispositivo no está configurado como propietario)</string>
+    <string name="kiosk_disabled">Modo kiosco desactivado</string>
+    <string name="status_no_wifi">Sin Wi-Fi</string>
+    <string name="status_no_internet">sin internet</string>
+    <string name="status_battery">%1$d%%</string>
+    <string name="status_battery_charging">Cargando %1$d%%</string>
 </resources>

app/src/main/res/xml/device_admin.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- No admin policies needed; device owner status alone enables Lock Task mode. -->
+<device-admin>
+    <uses-policies />
+</device-admin>