Platform Operation Exception
Flutnet provides a simple way to implement your custom exceptions in order to propagate the errors to the Flutter module: if you want to handle your exceptions in Flutter code, you need to extend the class PlatformOperationException.
All your custom errors will be generated by the $ flutnet pack command for your flutter project.
Example
In this example we are going to define a custom LoginException, with a custom error code.
This error will be handled in Flutter.
Custom error definition
LoginException.cs
using Flutnet.ServiceModel;
namespace my.library
{
// Error code
[PlatformData]
public enum LoginErrors
{
InvalidUsername,
InvalidPassword,
InvalidUsernameAndPassword,
}
// Custom error class
public class LoginException : PlatformOperationException
{
public LoginErrors Error { get; set; }
}
}
Throwing the error in a PlatformOperation
LoginService.cs
using Flutnet.ServiceModel;
namespace my.library
{
[PlatformService]
public class LoginService
{
[PlatformOperation]
public void Login(string username, string password)
{
// When login fails
throw new LoginException()
{
Error = LoginErrors.InvalidPassword
};
}
}
}
In Flutter project you just wrap your platform call with a try/catch
import 'package:flutter/material.dart';
import 'package:my_library/my/library/login_service.dart';
// Somewhere in your Dart code....
// Reference to the xamarin login service
final LoginService _loginService = LoginService("registration_key");
try {
// The best password ever ;-)
await _loginService.login(username: "admin", password: "admin");
} on LoginException catch (ex) {
// handle the LoginException error
} on PlatformOperationException catch (pe) {
// handle some other xamarin errors
} catch (ex) {
// handle some other errors
}