【问题标题】:Changing app navigation structure from version 4 to 5 in react native在 react native 中将应用导航结构从版本 4 更改为 5
【发布时间】:2020-05-29 18:48:02
【问题描述】:

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,这相当简单。

但我在将登录部分转换为版本 5 时遇到了困难,因为应用程序结构有些复杂,而且我对导航版本 5 的反应有些陌生。

我将在下面留下一个应用程序结构图,其中包含所使用的代码示例。

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。

【问题讨论】:

    标签: javascript android ios reactjs react-native


    【解决方案1】:

    在从 V4 迁移到 V5 时,您需要考虑几件事,这涉及到一些更改,您还可以考虑使用诸如挂钩之类的功能。

    第一个更改是移除 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。由于您已经有了基于 reducer 的实现,因此您可以使用状态值来做出此决定。

    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,现在一切都是组件,并且您将屏幕作为子项传递。

    该选项也作为道具发送到导航器或屏幕本身。

    navigation ref 的使用仍然是可能的,但您也可以在组件中使用 usenavigation 之类的钩子,并且对于您的身份验证流程,您不会使用它,因为您有条件地呈现导航器。

    我根据你的代码做了一个简化的版本。 应用.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>
      );
    }
    

    认证上下文

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

    授权减少器

    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,直到令牌从异步存储加载,然后基于该屏幕显示选项卡或登录屏幕。参数也作为道具传递。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

    希望对你有帮助,如有任何问题欢迎随时提问。

    【讨论】:

    • 你好@Guruparan Giritharan 很抱歉回复晚了,但我发现了一个问题,知道为什么身份验证过程不起作用我可以使用所有电子邮件登录,即使它们与我后端的电子邮件不匹配,我将令牌更改为我在后端服务器上使用的令牌仍然没有...
    • 你好@Max 我可以知道你是如何执行身份验证的吗?你能检查传递给你的服务调用的值吗?
    • 感谢您的回复,我有一个连接到 mongodb 数据库的后端节点 js 服务器我已经测试了身份验证,它运行良好我将在反应导航 v4 中留下后端服务器的链接我正在使用 AuthContext.js 中的代码(我在我的问题中提到的)来执行身份验证。这是后端服务器的链接:link
    • 假设你从身份验证函数返回 false 然后会发生什么,我看不出你的后端有什么问题
    • 是的,当我更新到您帮助我的代码时,后端与我的问题中的代码完美配合(反应导航 v4)一种我可以使用数据库中甚至不存在的电子邮件登录的方式我将使用您帮助我使用 React Navigation v5 [链接] (github.com/souhaildouqchi/MyNewsFront.git) 进行项目的方法将完整代码链接到项目中
    【解决方案2】:

    根据您的图表,我已尝试创建导航

    const WelcomeStack = createStackNavigator();
    const Tab = createBottomTabNavigator();
    const ArticleStack = createStackNavigator();
    const MainStack = createStackNavigator();
    
    function Welcome(){
    return(
        <WelcomeStack.Navigator>
            <WelcomeStack.screen name='SignIn' component={SignIn}/>
            <WelcomeStack.screen name='SignUp' component={SignUp}/>
        </WelcomeStack.Navigator>
    )
    }
    
    function  Article(){
    return(
        <ArticleStack.Navigator>
            <ArticleStack.Screen name='ArtcileList' name={ArticleList}/>
            <ArticleStack.Screen name='ArticleDetail' name={ArtcileDetail}/>
        </ArticleStack.Navigator>
    )
    }
    function TabNav(){
    <Tab.Navigator>
        <Tab.Screen name='Article' component={Article}/>
        <Tab.Screen name='Search' component={Search}/>
        <Tab.Screen name='Save' component={Save}/>
        <Tab.Screen name='Account' component={Account}/>
    </Tab.Navigator>
    }
    
    function App(){
    return(
    <NavigationContainer>
    <MainStack.Navigator>
       {this.state.isLogin ? 
       <MainStack.Screen name='Tab' component={TabNav}/> 
       :
       <MainStack.Screen name = 'WelcomeStack' component={Welcome}/>
      }
     </MainStack.Navigator>
     </NavigationContainer>
     )
     }
    

    在 React Navigation 5 中,它们不是切换导航器,因此您必须使用堆栈导航 + 三元运算符。 根据您的图表,这只是一个想法。经过一些研发,你可以让它变得更好。

    【讨论】:

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