有办法屏蔽点击返回事件吗？

[oshiwei]

var w = WillPopScope(
    child: Listener(
      behavior: HitTestBehavior.opaque,
      child: Center(
        child: Container(
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(5),
              color: Colors.black.withOpacity(0.7),
            ),
            padding: const EdgeInsets.all(20),
            child: CircularProgressIndicator(
              valueColor: AlwaysStoppedAnimation(Colors.white),
            )),
      ),
    ),
    onWillPop: () async {
      print("onWillPop");
      return false;
    },
  );
showToastWidget(w, duration: Duration.zero, handleTouch: true);

需要屏蔽安卓点击物理返回键事件，这样写监听不到，有没有什么办法？