flutter中手机系统自带返回事件触发判断

WillPopScope(
  onWillPop: _requestPop,
  child: pageContainer()
)

Future<bool> _requestPop() async {
  // 调用原生返回，返回原生页面，根据自身场景自己定义处理函数
  const platform = MethodChannel("flutterBackNative");
  try {
    final int res = await platform.invokeMethod("flutterBackNative");
  } on PlatformException catch (e) {
    print(e);
  }
  return Future.value(false);
}