Flutter 未處理的異常：無效參數（值）：不得為 null

Question

如果我提供 null 值，則此方法工作正常，它不會引發錯誤，但在更新到 flutter 2.1 后，現在如果我提供 null 值，它會引發異常，請為此提供最佳解決方案

  /// Method that saves the user lang in shared preferences
  static Future<dynamic> setLanguage (value) async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    return prefs.setString(_language, value);
  }

[錯誤：flutter/lib/ui/ui_dart_state.cc(199)] 未處理的異常：無效參數（值）：不能是 null

E/flutter (22502): #0 ArgumentError.checkNotNull (dart:core/errors.dart:185:27) E/flutter (22502): #1
SharedPreferences._setValue (package:shared_preferences/shared_preferences.dart:147:19) E/flutter (22502): #2 SharedPreferences.setString (package:shared_preferences/shared_preferences.ZBB14127678960FAE97D8733Z:72EA)

Answer 1

檢查值然后保存：

 static Future<dynamic> setLanguage (value) async {
    if (value != null){
      final SharedPreferences prefs = await SharedPreferences.getInstance();
      return prefs.setString(_language, value);
    }
   return null;
 }