SAF实现修改

lib/services/saf_storage_service.dart

@@ -1,15 +1,17 @@
 import 'dart:io';
 import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:shared_preferences/shared_preferences.dart';
-import 'package:file_picker/file_picker.dart';
 import '../models/saf_permission_state.dart';
 
-/// 使用 file_picker 实现文件夹访问
 class SafStorageService {
   static final SafStorageService _instance = SafStorageService._internal();
   factory SafStorageService() => _instance;
   SafStorageService._internal();
 
+  static const MethodChannel _channel = MethodChannel(
+    'com.lxh.battery_health/saf',
+  );
   static const String _prefKeySafPath = 'saf_storage_path';
   String? _cachedPath;
 
@@ -40,14 +42,13 @@ class SafStorageService {
 
   Future<SafAuthorizationResult> requestPermission() async {
     try {
-      // 使用 file_picker 选择文件夹
-      String? selectedPath = await FilePicker.platform.getDirectoryPath();
+      final String? selectedPath = await _channel.invokeMethod('selectFolder');
 
       if (selectedPath == null || selectedPath.isEmpty) {
         return SafAuthorizationResult.denied();
       }
 
-      // 验证路径是否包含 mbattery_charger（可选，提高容错）
+      // 验证路径是否包含 mbattery_charger
       if (!selectedPath.contains('mbattery_charger')) {
         return SafAuthorizationResult.error('请选择 mbattery_charger 文件夹');
       }
@@ -102,7 +103,7 @@ class SafStorageService {
       if (!await dir.exists()) return [];
       final entities = await dir.list().toList();
       return entities
-          .whereType<File>()
+          .where((e) => e is File)
           .map((e) => e.path.split(Platform.pathSeparator).last)
           .toList();
     } catch (e) {