Add hidden on-screen keyboard toggle (5 taps top-right corner)

Tap the top-right 60dp corner 5 times within 3 seconds to toggle
the soft keyboard on or off. Default is off (suppressed). The toggle
controls all suppression layers: JS inputmode injection, the
MutationObserver, InputMethodManager hide calls, and the WebView's
EditorInfo flags. A toast confirms the current state in Spanish.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -12,6 +12,9 @@ object AppConfig {
         "joykoo.mx",
     )
 
+    /** Size in dp of the corner regions used for hidden tap gestures. */
+    const val GESTURE_CORNER_DP = 60
+
     /** Number of rapid Back presses required to exit the app when there is no WebView history. */
     const val BACK_PRESS_EXIT_COUNT = 3
 
@@ -23,4 +26,10 @@ object AppConfig {
 
     /** Time window (ms) for admin tap sequence. */
     const val ADMIN_TAP_WINDOW_MS = 3000L
+
+    /** Number of taps on the top-right corner to toggle the on-screen keyboard. */
+    const val KEYBOARD_TOGGLE_TAP_COUNT = 5
+
+    /** Time window (ms) for keyboard toggle tap sequence. */
+    const val KEYBOARD_TOGGLE_TAP_WINDOW_MS = 3000L
 }

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

@@ -41,6 +41,10 @@ class MainActivity : AppCompatActivity() {
     // Admin exit: rapid taps in the top-left corner
     private var adminTapTimestamps = mutableListOf<Long>()
 
+    // Keyboard toggle: rapid taps in the top-right corner
+    private var keyboardToggleTapTimestamps = mutableListOf<Long>()
+    private var isKeyboardSuppressed = true
+
     // Back-press exit: rapid presses when no WebView history
     private var backPressTimestamps = mutableListOf<Long>()
 
@@ -213,11 +217,14 @@ class MainActivity : AppCompatActivity() {
 
     override fun dispatchTouchEvent(ev: MotionEvent): Boolean {
         if (ev.actionMasked == MotionEvent.ACTION_DOWN) {
-            // Top-left 60x60 dp region as the hidden admin area
-            val threshold = (60 * resources.displayMetrics.density).toInt()
+            val threshold = (AppConfig.GESTURE_CORNER_DP * resources.displayMetrics.density).toInt()
             if (ev.x < threshold && ev.y < threshold) {
                 handleAdminTap()
             }
+            val screenWidth = resources.displayMetrics.widthPixels
+            if (ev.x > screenWidth - threshold && ev.y < threshold) {
+                handleKeyboardToggleTap()
+            }
         }
         return super.dispatchTouchEvent(ev)
     }
@@ -234,7 +241,6 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun showAdminExitDialog() {
-        // Structured so a PIN check can be added here before calling finish()
         AlertDialog.Builder(this)
             .setTitle("Salir de la aplicación")
             .setMessage("¿Desea cerrar la aplicación del escáner?")
@@ -243,6 +249,35 @@ class MainActivity : AppCompatActivity() {
             .show()
     }
 
+    // ── Keyboard Toggle (hidden tap gesture, top-right corner) ──────────
+
+    private fun handleKeyboardToggleTap() {
+        val now = System.currentTimeMillis()
+        keyboardToggleTapTimestamps.add(now)
+        keyboardToggleTapTimestamps.removeAll {
+            now - it > AppConfig.KEYBOARD_TOGGLE_TAP_WINDOW_MS
+        }
+
+        if (keyboardToggleTapTimestamps.size >= AppConfig.KEYBOARD_TOGGLE_TAP_COUNT) {
+            keyboardToggleTapTimestamps.clear()
+            toggleKeyboard()
+        }
+    }
+
+    private fun toggleKeyboard() {
+        isKeyboardSuppressed = !isKeyboardSuppressed
+        webView.keyboardSuppressed = isKeyboardSuppressed
+
+        if (isKeyboardSuppressed) {
+            injectKeyboardSuppression(webView)
+            hideKeyboard()
+            Toast.makeText(this, R.string.keyboard_disabled, Toast.LENGTH_SHORT).show()
+        } else {
+            removeKeyboardSuppression(webView)
+            Toast.makeText(this, R.string.keyboard_enabled, Toast.LENGTH_SHORT).show()
+        }
+    }
+
     // ── Lifecycle ───────────────────────────────────────────────────────
 
     override fun onResume() {
@@ -291,15 +326,15 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun hideKeyboard() {
+        if (!isKeyboardSuppressed) return
         val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
         imm.hideSoftInputFromWindow(webView.windowToken, 0)
     }
 
     private fun injectKeyboardSuppression(view: WebView) {
+        if (!isKeyboardSuppressed) return
         view.evaluateJavascript("""
             (function() {
-                if (window.__jkKbSuppressed) return;
-                window.__jkKbSuppressed = true;
                 function suppress(el) {
                     if (el.tagName === 'INPUT' || el.tagName === 'TEXTAREA'
                         || el.isContentEditable) {
@@ -309,7 +344,8 @@ class MainActivity : AppCompatActivity() {
                 }
                 document.querySelectorAll('input, textarea, [contenteditable]')
                     .forEach(suppress);
-                new MutationObserver(function(muts) {
+                if (window.__jkKbObserver) window.__jkKbObserver.disconnect();
+                window.__jkKbObserver = new MutationObserver(function(muts) {
                     muts.forEach(function(m) {
                         m.addedNodes.forEach(function(n) {
                             if (n.nodeType === 1) {
@@ -320,12 +356,27 @@ class MainActivity : AppCompatActivity() {
                             }
                         });
                     });
-                }).observe(document.body || document.documentElement,
+                });
+                window.__jkKbObserver.observe(document.body || document.documentElement,
                     { childList: true, subtree: true });
             })();
         """.trimIndent(), null)
     }
 
+    private fun removeKeyboardSuppression(view: WebView) {
+        view.evaluateJavascript("""
+            (function() {
+                if (window.__jkKbObserver) {
+                    window.__jkKbObserver.disconnect();
+                    window.__jkKbObserver = null;
+                }
+                document.querySelectorAll('[inputmode="none"]').forEach(function(el) {
+                    el.removeAttribute('inputmode');
+                });
+            })();
+        """.trimIndent(), null)
+    }
+
     // ── WebViewClient ───────────────────────────────────────────────────
 
     private inner class ScannerWebViewClient : WebViewClient() {

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

@@ -26,6 +26,8 @@ import android.webkit.WebView
  */
 class NoSoftKeyboardWebView : WebView {
 
+    var keyboardSuppressed = true
+
     constructor(context: Context) : super(context)
     constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
     constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
@@ -33,17 +35,20 @@ class NoSoftKeyboardWebView : WebView {
 
     override fun onCreateInputConnection(outAttrs: EditorInfo): InputConnection? {
         val ic = super.onCreateInputConnection(outAttrs)
-        outAttrs.imeOptions = outAttrs.imeOptions or
-                EditorInfo.IME_FLAG_NO_EXTRACT_UI or
-                EditorInfo.IME_FLAG_NO_FULLSCREEN
-        post {
-            val imm = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
-            imm.hideSoftInputFromWindow(windowToken, 0)
+        if (keyboardSuppressed) {
+            outAttrs.imeOptions = outAttrs.imeOptions or
+                    EditorInfo.IME_FLAG_NO_EXTRACT_UI or
+                    EditorInfo.IME_FLAG_NO_FULLSCREEN
+            post {
+                val imm = context.getSystemService(Context.INPUT_METHOD_SERVICE)
+                        as InputMethodManager
+                imm.hideSoftInputFromWindow(windowToken, 0)
+            }
         }
         return ic
     }
 
     override fun onCheckIsTextEditor(): Boolean {
-        return false
+        return !keyboardSuppressed
     }
 }

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

@@ -4,4 +4,6 @@
     <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="keyboard_enabled">Teclado en pantalla activado</string>
+    <string name="keyboard_disabled">Teclado en pantalla desactivado</string>
 </resources>