Use SAF for Android

lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:file_picker/file_picker.dart';
 import 'package:flutter/material.dart';
+import 'package:saf/saf.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:sheetless/sheetview.dart';
 
@@ -33,6 +34,11 @@ class MyHomePage extends StatefulWidget {
 }
 
 class _MyHomePageState extends State<MyHomePage> {
+  @override
+  void initState() {
+    super.initState();
+  }
+
   Future<String?> getSavedSheetsPath() async {
     final prefs = await SharedPreferences.getInstance();
     return prefs.getString("sheets-path");
@@ -62,9 +68,31 @@ class _MyHomePageState extends State<MyHomePage> {
     return "No path selected";
   }
 
+  Future<String?> getSafPickedSheetsDirectory() async {
+    var pickedDirectories = await Saf.getPersistedPermissionDirectories();
+    if (pickedDirectories == null || pickedDirectories.isEmpty) {
+      return null;
+    }
+    return pickedDirectories.last;
+  }
+
   Future<List<Sheet>> acquireSheets() async {
-    var sheetsPath = await findAndSaveSheetsPath();
-    return loadSheetsSorted(sheetsPath);
+    String? sheetsDirectory = await getSafPickedSheetsDirectory();
+    if (sheetsDirectory == null || sheetsDirectory.isEmpty) {
+      Saf.getDynamicDirectoryPermission(grantWritePermission: false);
+      sheetsDirectory = await getSafPickedSheetsDirectory();
+      if (sheetsDirectory == null || sheetsDirectory.isEmpty) {
+        throw Exception("No Directory selected");
+      }
+    }
+
+    var sheetsDirectoryFiles = await Saf.getFilesPathFor(sheetsDirectory);
+    if (sheetsDirectoryFiles == null) {
+      Saf.releasePersistedPermissionFor(sheetsDirectory);
+      throw Exception(
+          "Permissions for directory no longer valid or Directory deleted. Please restart app.");
+    }
+    return loadSheetsSorted(sheetsDirectoryFiles);
   }
 
   @override