Flutter -使用TextEditingController检测键入的最后一个字符信息字段是否与特定字符匹配

TextEditingController controller = TextEditingController();

void checkLastCharacter() {
  String text = controller.text;
  if (text.isNotEmpty) {
    String lastCharacter = text.substring(text.length - 1);
    if (lastCharacter == '特定字符') {
      // 匹配成功的逻辑处理
    } else {
      // 匹配失败的逻辑处理
    }
  }
}

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      body: Center(
        child: TextField(
          controller: controller,
          onChanged: (value) {
            checkLastCharacter();
          },
        ),
      ),
    ),
  ));
}