前言
Hi, 接著就是來驗證登入狀態，如果已經登入就跳轉到首頁否則就在登入畫面，看完我這句話就知道要使用Bloc了，只要是畫面與功能就要使用到Bloc。以上是一個基本的狀態你還可以檢查有沒有重複登入等…。
完整程式碼
需要具備知識
Authentication：Event
事件分成三個，AppStarted用於開啟APP時觸發的事件，用來檢查有沒有登入，如果沒有就跳轉到登入介面，LoggedIn用於登入成功時觸發把未登入狀態切換成已登入狀態，最後就LoggedOut是登出按鈕觸發時使用，將已登入狀態切換成未登入狀態。
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| part of 'authentication_bloc.dart';
abstract class AuthenticationEvent extends Equatable {
const AuthenticationEvent();
@override
List<Object> get props => [];
}
class AppStarted extends AuthenticationEvent {}
class LoggedIn extends AuthenticationEvent {}
class LoggedOut extends AuthenticationEvent {}
|
Authentication：State
狀態可以分成兩個，未認證與認證，如果認證成功就切換到首頁否則就停留在登入畫面。
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| part of 'authentication_bloc.dart';
abstract class AuthenticationState extends Equatable {
const AuthenticationState();
@override
List<Object> get props => [];
}
class AuthenticationInitial extends AuthenticationState {}
class Authenticated extends AuthenticationState {
final String displayName;
const Authenticated(this.displayName);
@override
List<Object> get props => [displayName];
}
class Unauthenticated extends AuthenticationState {}
|
Authentication：Bloc
判斷三個事件所要觸法的功能，寫到這邊時大家應該都對這個架構感覺了吧，是不是覺得越來越美了呢。
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| import 'dart:async';
import 'dart:developer';
import 'package:bloc/bloc.dart';
import 'package:equatable/equatable.dart';
import 'package:stunning_tribble/infrastructure/auth/auth_repository.dart';
part 'authentication_event.dart';
part 'authentication_state.dart';
class AuthenticationBloc
extends Bloc<AuthenticationEvent, AuthenticationState> {
final AuthRepository _userRepository;
AuthenticationBloc({
required AuthRepository userRepository,
}) : _userRepository = userRepository,
super(AuthenticationInitial());
@override
Stream<AuthenticationState> mapEventToState(
AuthenticationEvent event,
) async* {
if (event is AppStarted) {
yield* _mapAppStartedToState();
} else if (event is LoggedIn) {
yield* _mapLoggedInToState();
} else if (event is LoggedOut) {
yield* _mapLoggedOutToState();
}
}
Stream<AuthenticationState> _mapAppStartedToState() async* {
final isSignedIn = await _userRepository.isSignedIn();
yield* isSignedIn.fold(
(failure) async* {
log("$failure");
yield Unauthenticated();
},
(isSignedInSuccess) async* {
yield* _mapLoggedInToState();
},
);
}
Stream<AuthenticationState> _mapLoggedInToState() async* {
final user = await _userRepository.getUser();
yield* user.fold(
(failure) async* {
log("$failure");
yield Unauthenticated();
},
(user) async* {
yield Authenticated(user.displayName.toString());
},
);
}
Stream<AuthenticationState> _mapLoggedOutToState() async* {
final signOut = await _userRepository.signOut();
yield* signOut.fold(
(failure) async* {
log("$failure");
yield Unauthenticated();
},
(r) async* {
yield Unauthenticated();
},
);
}
}
|