「2」expo-shopping：组织代码结构

前面我们已经准备好了expo router，现在我们来写页面

首先我们先定义一个auth用于全局的用户操作，新建context/auth.tsx

tsx 复制代码

import { createContext, useContext, useState } from "react";

const AuthContext = createContext({
  user: null,
  signIn: (val: any) => {},
  signOut: () => {},
});

export const useAuth = () => useContext(AuthContext);

export function AuthProvider({
  children,
  userCredentials,
}: {
  children: any;
  userCredentials: any;
}) {
  const [user, setAuth] = useState(userCredentials);

  return (
    <AuthContext.Provider
      value={{
        signIn: (userCredentials) => setAuth(userCredentials),
        signOut: () => setAuth(null),
        user,
      }}>
      {children}
    </AuthContext.Provider>
  );
}

主要抛出一个useAuth一个AuthProvider来包裹layout，达到复用context的作用

页面

我们现在来编写页面结构，结构如下：

新建app/_layout.tsx

tsx 复制代码

import { Stack } from "expo-router";
import { useState } from "react";

import { AuthProvider } from "../context/auth";

export default function Layout() {
  const [loadedUser, setLoadedUser] = useState(null);

  return (
    <AuthProvider userCredentials={loadedUser}>
      <Stack>
        <Stack.Screen
          name="(main)/(tabs)"
          options={{
            headerShown: false,
          }}></Stack.Screen>
      </Stack>
    </AuthProvider>
  );
}

用于在首次进入页面的时候，进入指向(main)/(tabs)下面的页面

新建关于页app/about.tsx

tsx 复制代码

import { useLocalSearchParams, useRouter } from "expo-router";
import { View, Text } from "react-native";

export default function Details() {
  const router = useRouter();
  const params = useLocalSearchParams();

  return (
    <View style={{ flex: 1, alignItems: "center", justifyContent: "center" }}>
      <Text
        onPress={() => {
          router.setParams({ name: "Updated" });
        }}>
        Update the title
      </Text>
    </View>
  );
}

这种路由地址和文件系统路径有关，至于(auth)``(main)这种其实是一样的目录，只是为了方便组织文件，做的路由分组

新建登录页app/(auth)/login.tsx

tsx 复制代码

import { useLocalSearchParams, useRouter } from "expo-router";
import { useState } from "react";
import { Pressable, Text, View } from "react-native";

import { useAuth } from "../../context/auth";

export default function Login() {
  const router = useRouter();
  const params = useLocalSearchParams();

  const [email, setEmail] = useState("[email protected]");

  const { signIn } = useAuth();

  const onLogin = async () => {
    signIn({ email });
    router.back();
  };

  return (
    <View>
      <Pressable onPress={onLogin}>
        <Text>Login</Text>
      </Pressable>
    </View>
  );
}

tabs导航栏页面，我们先新建app/(main)/(tabs)/cart.tsx, app/(main)/(tabs)/category.tsx,app/(main)/(tabs)/profile.tsx,app/(main)/(tabs)/index.tsx 并且都填入类似的初始化代码：

tsx 复制代码

import { View, Text } from "react-native";

export default function Profile() {
  return (
    <View>
      <Text>Profile screen</Text>
    </View>
  );
}

因为我们目前只是组织项目结构，所以不急于写代码

然后我们修改app/(main)/(tabs)/_layout.tsx

tsx 复制代码

import { FontAwesome } from "@expo/vector-icons";
import { Tabs } from "expo-router";

export default function Layout() {
 return (
   <Tabs
     screenOptions={{
       tabBarActiveTintColor: "#05bfdb",
     }}>
     <Tabs.Screen
       name="index"
       options={{
         title: "feed",
         tabBarIcon: ({ color }) => <FontAwesome name="home" size={24} color={color} />,
       }}
     />
     <Tabs.Screen
       name="category"
       options={{
         tabBarIcon: ({ color }) => <FontAwesome name="search" size={24} color={color} />,
       }}
     />
     <Tabs.Screen
       name="cart"
       options={{
         tabBarIcon: ({ color }) => <FontAwesome name="bell" size={24} color={color} />,
       }}
     />
     <Tabs.Screen
       name="profile"
       options={{
         tabBarIcon: ({ color }) => <FontAwesome name="user" size={24} color={color} />,
       }}
     />
   </Tabs>
 );
}

囊括每一个tab的screen，注意这里需要安装@expo/vector-icons依赖：

shell 复制代码

npx expo install @expo/vector-icons

好了现在打开页面效果如下：

代码地址：github.com/liyunfu1998...