How do I call a method as a parameter from a subclass in the Object class in dart? - flutter

Question

I have a method inside a service class:
#override
Future<String> registerNewVoter(Object deviceAppInfo) async {
Dio dio = new Dio();
final url = API().endpointVoterUri(EndpointVoter.newVoter).toString();
final header = {'Content-type': 'application/json'};
final data = await deviceAppInfo; ///need to call the method getInfo() on the Object class which returns a future
final response =
await dio.post(url, data: data, options: Options(headers: header));
if (response.statusCode == 200) {
Map map = response.data;
final uuid = map['result']['voter_uuid'];
return uuid;
}
print(
'Request $url failed\nResponse: ${response.statusCode} ${response.statusMessage}');
throw response;
}
I'm using type Object deviceAppInfo as a parameter in the method to keep the service as pure as possible(adhering to mvvm principles). The subclass is DeviceAppInfo which has an async method called getInfo()(and where the data comes from) which is supposed to be assigned to data(see the comments in the code). I'm struggling to see how I can keep the class decoupled from DeviceAppInfo class. Any suggestions...? I'm thinking of calling a factory constructor but not sure how to implement it. Here is my DeviceAppInfo class:
class DeviceAppInfo {
DeviceAppInfo({
this.platform,
this.platformVersion,
this.appVersion,
});
final String platform;
final String platformVersion;
final String appVersion;
Map<String, dynamic> toMap() => {
'platform': this.platform,
'platform_version': this.platformVersion,
'app_version': this.appVersion,
};
Future<Map<String, dynamic>> getInfo() async {
final values = await Future.wait([
getPlatform(),
getPlatformVersion(),
getProjectVersion(),
]);
return DeviceAppInfo(
platform: values[0],
platformVersion: values[1],
appVersion: values[2],
).toMap();
}
Future<String> getPlatform() async {
try {
if (Platform.isIOS) {
return 'ios';
}
return 'android';
} on PlatformException catch (e) {
return e.toString();
}
}
Future<String> getPlatformVersion() async {
try {
final platformVersion = await GetVersion.platformVersion;
return platformVersion;
} on PlatformException catch (e) {
return e.toString();
}
}
Future<String> getProjectVersion() async {
try {
final projectVersion = await GetVersion.projectVersion;
return projectVersion;
} on PlatformException catch (e) {
return e.toString();
}
}
}

Answer 1

I believe that DeviceAppInfo is a clear collaborator of your service, and hiding it behind Object is simply bad engineering:
it will make your Api hard to use correctly and easy to use incorrectly
Your api is no longer self-documenting, without reading the docs or code it is impossible to use it correctly.
However, it can be discussed if it should be exposed as a parameter or provided to the constructor of your service.
Having said that, There are at least 3 options that will decouple your service from DeviceAppInfo:
Option 1: Pass in the result of getInfo() to your method
least questionable and a common form of decoupling inbound data
I am a bit sceptical if you use a Map as an input type, it is still easy to provide a map with incorrect keys
Option 2: take a function as an argument
Function a bit harder to use, it is not evident what functions accross the codebase can be used (compared to a class)
Option 3: cast to dynamic
Please dont do that
Most closely matches your goal from question
function is extremely hard to use correctly Without reading docs / code
You change compile-time errors to runtime errors

Answer 2

Is this what you want?
#override
Future<String> registerNewVoter(DeviceAppInfo deviceAppInfo) async {
Dio dio = new Dio();
final url = API().endpointVoterUri(EndpointVoter.newVoter).toString();
final header = {'Content-type': 'application/json'};
final data = await deviceAppInfo.getInfo();
final response =
await dio.post(url, data: data, options: Options(headers: header));
if (response.statusCode == 200) {
Map map = response.data;
final uuid = map['result']['voter_uuid'];
return uuid;
}
print(
'Request $url failed\nResponse: ${response.statusCode} ${response.statusMessage}');
throw response;
}
NOTE: I just changed the type of deviceAppInfo from Object to DeviceAppInfo