Big commit.

Managed to do upload and download right. No Race conditions.

app/src/main/java/com/dano/test1/HandlerOpeningScreen.kt

@@ -9,6 +9,7 @@ import android.widget.*
 import kotlinx.coroutines.*
 import org.json.JSONArray
 import android.util.Log
+import java.io.File
 
 
 var INTEGRATION_INDEX_POINTS: Int? = null
@@ -35,6 +36,7 @@ class HandlerOpeningScreen(private val activity: MainActivity) {
         activity.setContentView(R.layout.opening_screen)
 
         bindViews()
+
         loadQuestionnaireOrder()
         createQuestionnaireButtons()
         restorePreviousClientCode()
@@ -46,11 +48,22 @@ class HandlerOpeningScreen(private val activity: MainActivity) {
         setupUploadButton()
         setupDownloadButton()
 
+        val dbPath = "/data/data/com.dano.test1/databases/questionnaire_database"
+        val pathExists = File(dbPath).exists()
+        if (pathExists) {
+            updateMainButtonsState(true)
+        }
+        else{
+            updateMainButtonsState(false)
+        }
+
         if (!editText.text.isNullOrBlank()) {
             buttonLoad.performClick()
         }
+
     }
 
+
     private fun bindViews() {
         editText = activity.findViewById(R.id.editText)
         spinner = activity.findViewById(R.id.string_spinner1)
@@ -183,13 +196,12 @@ class HandlerOpeningScreen(private val activity: MainActivity) {
             }
 
             withContext(Dispatchers.Main) {
+                updateMainButtonsState(true) // Datenbank vorhanden -> Buttons aktivieren
                 handleNormalLoad(clientCode)
             }
         }
     }
 
-
-
     private suspend fun handleNormalLoad(clientCode: String) {
         val completedIds = withContext(Dispatchers.IO) {
             MyApp.database.completedQuestionnaireDao().getCompletedQuestionnairesForClient(clientCode)
@@ -559,6 +571,22 @@ class HandlerOpeningScreen(private val activity: MainActivity) {
         }
     }
 
+    // --- Füge diese Funktion in deine Klasse ein ---
+    private fun isDatabasePopulated(): Boolean {
+        return try {
+            // Wir prüfen, ob die Datenbank mindestens eine nicht-interne Tabelle enthält.
+            // Das ist robust gegenüber verschiedenen Tabellennamen.
+            val db = MyApp.database.openHelper.readableDatabase
+            val cursor = db.query(
+                "SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%' AND name != 'room_master_table'"
+            )
+            cursor.use { it.count > 0 }
+        } catch (e: Exception) {
+            // Falls etwas schiefgeht (z.B. DB noch nicht vorhanden), gilt: nicht vorhanden
+            false
+        }
+    }
+
     private fun setupDownloadButton() {
         downloadButton.text = "Download"
         downloadButton.setOnClickListener {
@@ -568,7 +596,15 @@ class HandlerOpeningScreen(private val activity: MainActivity) {
 
             Toast.makeText(activity, "Datenbank wird heruntergeladen...", Toast.LENGTH_SHORT).show()
             DatabaseDownloader.downloadAndReplaceDatabase(activity)
+            updateMainButtonsState(true)
         }
     }
 
+    private fun updateMainButtonsState(isDatabaseAvailable: Boolean) {
+        val buttons = listOf(buttonLoad, saveButton, editButton)
+        buttons.forEach { button ->
+            button.isEnabled = isDatabaseAvailable
+            button.alpha = if (isDatabaseAvailable) 1.0f else 0.5f
+        }
+    }
 }