feat: add support for user-selected export directories; implement DocumentFile integration for CSV exports

CollabTableAndroid/app/build.gradle

@@ -96,6 +96,8 @@ dependencies {
 
     // Reorderable LazyColumn for drag-and-drop
     implementation 'org.burnoutcrew.composereorderable:reorderable:0.9.6'
+    // DocumentFile (SAF) support for user-selected export directories
+    implementation 'androidx.documentfile:documentfile:1.0.1'
 }
 
 // Ktlint configuration

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/ListsScreen.kt

@@ -29,6 +29,9 @@ import androidx.compose.material.icons.filled.DragHandle
 import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.List
 import androidx.compose.material.icons.filled.Share
+import android.net.Uri
+import android.content.Intent
+import androidx.documentfile.provider.DocumentFile
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DropdownMenu
@@ -105,6 +108,7 @@ fun ListsScreen(
     var listToDelete by remember { mutableStateOf<CollabList?>(null) }
     var listToEdit by remember { mutableStateOf<CollabList?>(null) }
     var listToExport by remember { mutableStateOf<CollabList?>(null) }
+    var exportTargetUri by remember { mutableStateOf<Uri?>(null) }
     val coroutineScope = rememberCoroutineScope()
 
     Scaffold(
@@ -345,22 +349,38 @@ fun ListsScreen(
     }
     // Export dialog (top-level) separate from create/edit/delete dialogs
     listToExport?.let { list ->
+        val folderPicker = rememberLauncherForActivityResult(ActivityResultContracts.OpenDocumentTree()) { uri ->
+            if (uri != null) {
+                // Take persistable permission for potential reuse during this session
+                try {
+                    val flags = Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+                    context.contentResolver.takePersistableUriPermission(uri, flags)
+                } catch (_: Exception) { }
+                exportTargetUri = uri
+            }
+        }
         ExportListDialog(
             list = list,
-            onDismiss = { listToExport = null },
+            selectedDirectoryLabel = exportTargetUri?.let { uri ->
+                DocumentFile.fromTreeUri(context, uri)?.name ?: uri.lastPathSegment ?: "(selected)"
+            } ?: "App storage (default)",
+            onSelectDirectory = { folderPicker.launch(null) },
+            onDismiss = { listToExport = null; exportTargetUri = null },
             onConfirmExport = { format ->
                 if (format == "CSV") {
                     coroutineScope.launch {
-                        val result = viewModel.exportListToCsv(list.id, list.name)
+                        val result = viewModel.exportListToCsv(list.id, list.name, exportTargetUri)
                         result.onSuccess { path ->
                             Toast.makeText(context, context.getString(R.string.export_success, path), Toast.LENGTH_LONG).show()
                         }.onFailure {
                             Toast.makeText(context, context.getString(R.string.export_error), Toast.LENGTH_LONG).show()
                         }
                         listToExport = null
+                        exportTargetUri = null
                     }
                 } else {
                     listToExport = null
+                    exportTargetUri = null
                 }
             },
         )
@@ -572,6 +592,8 @@ private fun SortMenu(prefs: PreferencesManager) {
 @Composable
 private fun ExportListDialog(
     list: CollabList,
+    selectedDirectoryLabel: String,
+    onSelectDirectory: () -> Unit,
     onDismiss: () -> Unit,
     onConfirmExport: (String) -> Unit,
 ) {
@@ -594,6 +616,9 @@ private fun ExportListDialog(
                         )
                     }
                 }
+                // Directory selection (optional, per export only)
+                Text("Directory: $selectedDirectoryLabel", style = MaterialTheme.typography.bodySmall)
+                TextButton(onClick = onSelectDirectory) { Text("Select Directory") }
             }
         },
         confirmButton = {

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/ListsViewModel.kt

@@ -19,6 +19,8 @@ import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import java.io.File
+import android.net.Uri
+import androidx.documentfile.provider.DocumentFile
 import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.UUID
@@ -234,7 +236,9 @@ class ListsViewModel(
     suspend fun exportListToCsv(
         listId: String,
         listName: String,
-    ): Result<String> = try {
+        targetTreeUri: Uri? = null,
+    ): Result<String> {
+        return try {
         // Load fields (ordered) and items with values
         val fields: List<Field> = database.fieldDao().getFieldsForList(listId).first()
         val items: List<ItemWithValues> = database.itemDao().getItemsWithValuesForList(listId).first()
@@ -263,15 +267,33 @@ class ListsViewModel(
         val safeBase = listName.lowercase(Locale.US).replace("[^a-z0-9]+".toRegex(), "_").trim('_').ifBlank { "table" }
         val ts = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date())
         val fileName = "${safeBase}_${ts}.csv"
+            if (targetTreeUri != null) {
+                val docTree = DocumentFile.fromTreeUri(context, targetTreeUri)
+                if (docTree == null || !docTree.isDirectory || !docTree.canWrite()) {
+                    return Result.failure(IllegalStateException("Selected folder not writable"))
+                }
+                docTree.findFile(fileName)?.delete()
+                val created = docTree.createFile("text/csv", fileName)
+                if (created == null) {
+                    return Result.failure(IllegalStateException("Failed to create file in selected folder"))
+                }
+                context.contentResolver.openOutputStream(created.uri)?.use { os ->
+                    os.write(csv.toByteArray())
+                } ?: return Result.failure(IllegalStateException("Failed to open output stream"))
+                Logger.i("Tables", "📤 Exported table '$listName' to CSV (SAF): ${created.uri}")
+                Result.success(created.uri.toString())
+            } else {
                 val dir = context.getExternalFilesDir(null) ?: context.filesDir
                 val file = File(dir, fileName)
                 file.writeText(csv)
                 Logger.i("Tables", "📤 Exported table '$listName' to CSV: ${file.absolutePath}")
                 Result.success(file.absolutePath)
+            }
         } catch (e: Throwable) {
             Logger.e("Tables", "❌ Export failed: ${e.message}")
             Result.failure(e)
         }
+    }
 
     private fun escapeCsv(value: String): String {
         if (value.isEmpty()) return ""