SharedPreferencesで文字列配列の取得・設定例

gistfile1.txt

  getMessages() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    List<String> messages = await prefs.getStringList("messages") ?? List<String>();
    setState(() {
      _messages = messages.map((message) {
        return Message(message: message,);
      }).toList() ;
    });
 }

  saveMessages() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();

    List<String> messages = _messages.map((message) {
      return message.message;
    }).toList();

    await prefs.setStringList("messages", messages);
  }