function - Dart:从函数访问调用者实例

Question

如何从函数访问“调用者”实例。以下代码引发语法错误:

// Error: Local variables cannot be referenced before they are declared
Function listener = (Event event) {
   print(listener);
};

我想从函数内部访问“listener”变量。谢谢。

Answer 1

Function listener;
listener = (Event event) {
  print(listener);
}