javascript - 在 React Native 中将应用程序导航结构从版本 4 更改为版本 5

Question

我正在使用 React Navigation 版本 4 开发一个旧应用程序，该应用程序显然包含一个注册和登录页面，然后是应用程序的内容。

最近我开始使用 React Navigation 版本 5 重新制作应用程序的内容，以便使用共享元素动画和底部选项卡导航器，这非常简单。

但我很难将登录部分转换为版本 5，因为应用程序结构有些复杂，而且我对 React 导航版本 5 还有些陌生。

我将在下面留下应用程序结构图和所用代码示例。

App.js :

import { setNavigator } from "./app/navigationRef";
const articleListFlow = createStackNavigator({
  Main: MainScreen, // screen with diffrent articles categories
  ResultsShow: ResultShowScreen, // article details screen
});
const loginFlow = createStackNavigator({
  Signup: SignupScreen,
  Signin: SigninScreen,
});
loginFlow.navigationOptions = () => {
  return {
    headerShown: false,
  };
};

articleListFlow.navigationOptions = {
  title: "News Feed",
  tabBarIcon: ({ tintColor }) => (
    <View>
      <Icon style={[{ color: tintColor }]} size={25} name={"ios-cart"} />
    </View>
  ),
  activeColor: "#ffffff",
  inactiveColor: "#ebaabd",
  barStyle: { backgroundColor: "#d13560" },
};
const switchNavigator = createSwitchNavigator({
  ResolveAuth: ResolveAuthScreen,
  MainloginFlow: createSwitchNavigator({
    //WelcomeScreen: WeclomeScreen,
    loginFlow: loginFlow,
  }),

  mainFlow: createMaterialBottomTabNavigator(
    {
      articleListFlow: articleListFlow,
      ArticleSave: ArticleSaveScreen, // we dont need this one
      Account: AccountScreen,
    },
    {
      activeColor: "#ffffff",
      inactiveColor: "#bda1f7",
      barStyle: { backgroundColor: "#6948f4" },
    }
  ),
});
const App = createAppContainer(switchNavigator);
export default () => {
  return (
    <AuthProvider>
      <App
        ref={(navigator) => {
          setNavigator(navigator);
        }}
      />
    </AuthProvider>
  );
};

NavigationRef.js :

import { NavigationActions } from "react-navigation";

let navigator;

export const setNavigator = (nav) => {
  navigator = nav;
};

export const navigate = (routeName, params) => {
  navigator.dispatch(
    NavigationActions.navigate({
      routeName,
      params,
    })
  );
};

// routename is the name of the routes singin singup accountscreen
// params information we want to pass to the screen we want to show

AuthContext.js

import { AsyncStorage } from "react-native";
import createDataContext from "./createDataContext";
import userAPI from "../api/user";

// using navigate to access the navigator and redirect the user
import { navigate } from "../navigationRef";

// AUTHENTICATION REDUCERS
const authReducer = (state, action) => {
  switch (action.type) {
    case "add_error": {
      return {
        ...state,
        errorMessage: action.payload,
      };
    }

    case "clear_error_message": {
      return {
        ...state,
        errorMessage: "",
      };
    }
    case "signin": {
      return {
        errorMessage: "",
        token: action.payload,
      };
    }

    default:
      return state;
  }
};

// CLEARING ERROR MESSAGES WHEN SWITCHING SIGNIN-SIGNUP
const clearErrorMessage = (dispatch) => () => {
  dispatch({ type: "clear_error_message" });
};

// AUTOMATIC SIGNIN ONLY USING TOKENS ON USER DEVICE
const tryLocalSignin = (dispatch) => async () => {
  const token = await AsyncStorage.getItem("token");
  if (token) {
    // if token exists
    dispatch({ type: "signin", payload: token });

    navigate("Main");
  } else {
    // if token doesnt exist
    navigate("WelcomeScreen");
  }
};

// SIGNUP
const signup = (dispatch) => async ({ email, password }) => {
  try {
    const response = await userAPI.post("/signup", { email, password });
    await AsyncStorage.setItem("token", response.data.token);
    dispatch({ type: "signin", payload: response.data.token });

    // making use of the navigate component to access navigation
    // and redirect the user
    navigate("Main");
  } catch (err) {
    dispatch({
      type: "add_error",
      payload: "Something went wrong with sign up",
    });
  }
};

// SIGNIN
const signin = (dispatch) => async ({ email, password }) => {
  try {
    const response = await userAPI.post("/signin", { email, password });
    await AsyncStorage.setItem("token", response.data.token);
    // using signin since the logic is the same
    dispatch({ type: "signin", payload: response.data.token });

    // making use of the navigate component to access navigation
    // and redirect the user
    navigate("Main");
  } catch (err) {
    console.log(err);
    dispatch({
      type: "add_error",
      payload: "Something went wrong with sign in",
    });
  }
};

// SIGNOUT
const signout = (dispatch) => async () => {
  // removing the token makes identification not work again
  await AsyncStorage.removeItem("token");
  dispatch({ type: "signout" });

  navigate("loginFlow");
};

// CREATING CONTEXT AND PROVIDER OBJECTS FOR AUTHENTICATION
export const { Provider, Context } = createDataContext(
  authReducer,
  {
    signin,
    signup,
    signout,
    clearErrorMessage,
    tryLocalSignin,
  },
  {
    token: null,
    errorMessage: "",
  }
);

createDataContext.js

import React, { useReducer } from "react";

export default (reducer, actions, defaultValue) => {
  const Context = React.createContext();

  const Provider = ({ children }) => {
    const [state, dispatch] = useReducer(reducer, defaultValue);

    const boundActions = {};

    for (let action in actions) {
      // for every action in the actions, call it with dispatch
      boundActions[action] = actions[action](dispatch);
    }

    return (
      <Context.Provider value={{ state, ...boundActions }}>
        {children}
      </Context.Provider>
    );
  };

  return { Context, Provider };
};

对于长代码，我深表歉意，并提前感谢任何可以提供帮助的人。

Answer 1

从 V4 迁移到 V5 时，您需要考虑几件事情，它涉及一些更改，您还可以考虑使用 Hook 等功能。

第一个更改是删除 Switch Navigator 并有条件地在其位置呈现导航器。这将在您的 App.js 中完成。由于您已经有一个基于 reducer 的实现，您可以使用状态值来做出这个决定。

下一个变化将是堆栈的创建，在 V4 中，您通过传递屏幕来创建导航，现在一切都是一个组件，您将屏幕作为子项传递。

选项也作为 Prop 发送给导航器或屏幕本身。

navigation ref的用法仍然可行，但您也可以在组件内部使用诸如 usenavigation 之类的 Hook ，并且对于您的身份验证流程，您不会在有条件地呈现导航器时使用它。

我根据你的代码做了一个简化版。应用程序.js

const AuthStack = createStackNavigator();
const AppTabs = createMaterialBottomTabNavigator();
const ArticleStack = createStackNavigator();

const Articles = () => {
  return (
    <ArticleStack.Navigator>
      <AppTabs.Screen name="ArticlesList" component={ArticleList} />
      <AppTabs.Screen name="ArticlesDetails" component={ArticleDetail} />
    </ArticleStack.Navigator>
  );
};

export default function App() {
  const [state, dispatch] = React.useReducer(authReducer, {
    isLoading: true,
    token: null,
    errorMessage: '',
  });

  React.useEffect(() => {
    const bootstrapAsync = async () => {
      const userToken = await AsyncStorage.getItem('userToken');
      dispatch({ type: 'RESTORE_TOKEN', token: userToken });
    };

    bootstrapAsync();
  }, []);
  const authContext = React.useMemo(
    () => ({
      signIn: async (data) => {
        dispatch({ type: 'SIGN_IN', token: 'dummy-auth-token' });
      },
      signOut: () => dispatch({ type: 'SIGN_OUT' }),
      signUp: async (data) => {
        dispatch({ type: 'SIGN_IN', token: 'dummy-auth-token' });
      },
    }),
    []
  );

  return (
    <AuthContext.Provider value={authContext}>
      <NavigationContainer>
        {state.token === null ? (
          <AuthStack.Navigator headerMode="none">
            {state.isLoading ? (
              <AuthStack.Screen name="Welcome" component={WelcomeScreen} />
            ) : (
              <>
                <AuthStack.Screen name="SignIn" component={SignInScreen} />
                <AuthStack.Screen name="SignUp" component={SingUpScreen} />
              </>
            )}
          </AuthStack.Navigator>
        ) : (
          <AppTabs.Navigator
            activeColor="#f0edf6"
            inactiveColor="#3e2465"
            barStyle={{ backgroundColor: '#694fad' }}>
            <AppTabs.Screen
              name="Articles"
              component={Articles}
              options={{
                tabBarLabel: 'Home',
                tabBarIcon: ({ color, size }) => (
                  <MaterialCommunityIcons
                    name="home"
                    color={color}
                    size={size}
                  />
                ),
              }}
            />
            <AppTabs.Screen name="Search" component={SearchScreen} />
            <AppTabs.Screen name="Save" component={SaveScreen} />
            <AppTabs.Screen name="Account" component={AccountScreen} />
          </AppTabs.Navigator>
        )}
      </NavigationContainer>
    </AuthContext.Provider>
  );
}

授权上下文

const AuthContext = React.createContext();
export default AuthContext;

授权 reducer

export const authReducer = (state, action) => {
  switch (action.type) {
    case 'RESTORE_TOKEN':
      return {
        ...state,
        token: action.token,
        isLoading: false,
      };

    case 'SIGN_IN': {
      return {
        errorMessage: '',
        token: action.payload,
      };
    }

    case 'SIGN_OUT': {
      return {
        errorMessage: '',
        token: null,
      };
    }

    default:
      return state;
  }
};

如您所见，流程将显示欢迎屏幕，直到从异步存储加载 token ，然后基于此显示选项卡或登录屏幕。参数也作为 Prop 传递。我已将操作移至 app.js，但它也可以分开。

您可以在此处查看完整运行的示例 https://snack.expo.io/@guruparan/navigation-sample-3

希望对您有所帮助，如有任何问题，欢迎随时提问。