feat:增加消息记录功能

lib/utils/sp_utils.dart

@@ -0,0 +1,23 @@
+import 'package:shared_preferences/shared_preferences.dart';
+
+class SpUtil {
+  static late SharedPreferences _sp;
+
+  static Future<void> init() async {
+    _sp = await SharedPreferences.getInstance();
+  }
+
+  static Future<bool> setString(String key, String value) =>
+      _sp.setString(key, value);
+
+  static String? getString(String key) => _sp.getString(key);
+
+  static Future<bool> setInt(String key, int value) =>
+      _sp.setInt(key, value);
+
+  static int? getInt(String key) => _sp.getInt(key);
+
+  static Future<bool> remove(String key) => _sp.remove(key);
+
+  static Future<bool> clear() => _sp.clear();
+}