小编Jag*_*ngh的帖子

I am making an application using flutter framework . During this I came across with the keywords in Dart "async" and "async*". Can anybody tell me what's the difference between them? Thanks in advance.

由于驱动器损坏，我丢失了 Flutter 应用程序的源代码，但debug.apk我的 android 手机中有我的源代码。谁能告诉我如何反编译 Flutterapk以获取源代码。我尝试使用反编译器反编译它，但它没有提供我的源代码，因为 flutter 源代码是 dart 语言。

我正在使用flutter应用程序，我想检查警报对话框是否在屏幕上打开。谁能告诉我该怎么做，基本上我想在警报对话框打开和关闭之前和之后做一些事情。

基本上我试图在 FCMonBackgroundMessage触发时发出通知。在执行此操作时，我获得了FlutterLocalNotification 插件NullPointerException的.show(..)方法。

这是我的代码：

 FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
    _firebaseMessaging.configure(
      onMessage: (Map<String, dynamic> message) async {
        print("onMessage: $message");
      },
      onBackgroundMessage: messageHandle,
      onLaunch: (Map<String, dynamic> message) async {
        print("onLaunch: $message");
      },
      onResume: (Map<String, dynamic> message) async {
        print("onResume: $message");
      },
    );
Future<dynamic> messageHandle(Map<String, dynamic> message) async{
  if (message.containsKey("data")) {
    Map data = message['data'];
    String topic;
    if (data.containsKey("topic")) topic = data['topic'];
    if (topic == "VendorNewTrips") {
      String amount = data['amount'];
      String vehicle = data['vehicle'];
      String tripType = …