React Native的導航欄隱藏與顯示邏輯

在React Native中，可以使用react-navigation庫來實現導航欄的隱藏與顯示。以下是一個簡單的示例，展示了如何在React Native應用中實現導航欄的隱藏與顯示邏輯：

1. 首先，確保已經安裝了react-navigation庫及其相關依賴。如果尚未安裝，可以使用以下命令進行安裝：

npm install @react-navigation/native @react-navigation/stack

2. 創建一個堆棧導航器（Stack Navigator），并在其中添加兩個屏幕組件。例如，創建一個名為HomeScreen和DetailsScreen的屏幕組件：

// HomeScreen.js
import React from 'react';
import { View, Text, Button } from 'react-native';

const HomeScreen = ({ navigation }) => {
  return (
    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
      <Text>Home Screen</Text>
      <Button
        title="Go to Details Screen"
        onPress={() => navigation.navigate('Details')}
      />
    </View>
  );
};

export default HomeScreen;

// DetailsScreen.js
import React from 'react';
import { View, Text } from 'react-native';

const DetailsScreen = () => {
  return (
    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
      <Text>Details Screen</Text>
    </View>
  );
};

export default DetailsScreen;

3. 在主組件（例如App.js）中，創建一個堆棧導航器實例，并將HomeScreen和DetailsScreen添加到其中：

// App.js
import React from 'react';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import HomeScreen from './HomeScreen';
import DetailsScreen from './DetailsScreen';

const Stack = createStackNavigator();

const App = () => {
  return (
    <NavigationContainer>
      <Stack.Navigator initialRouteName="Home">
        <Stack.Screen name="Home" component={HomeScreen} />
        <Stack.Screen name="Details" component={DetailsScreen} />
      </Stack.Navigator>
    </NavigationContainer>
  );
};

export default App;

4. 要實現導航欄的隱藏與顯示邏輯，可以使用navigationOptions屬性中的headerShown選項。將其設置為false可以隱藏導航欄，設置為true（或省略該選項）可以顯示導航欄。

以下是一個示例，展示了如何在HomeScreen和DetailsScreen中分別隱藏和顯示導航欄：

// HomeScreen.js
import React from 'react';
import { View, Text, Button } from 'react-native';

const HomeScreen = ({ navigation }) => {
  return (
    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
      <Text>Home Screen</Text>
      <Button
        title="Go to Details Screen"
        onPress={() => navigation.navigate('Details')}
      />
    </View>
  );
};

HomeScreen.navigationOptions = {
  headerShown: false, // 隱藏導航欄
};

export default HomeScreen;

// DetailsScreen.js
import React from 'react';
import { View, Text } from 'react-native';

const DetailsScreen = () => {
  return (
    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
      <Text>Details Screen</Text>
    </View>
  );
};

DetailsScreen.navigationOptions = {
  headerShown: true, // 顯示導航欄
};

export default DetailsScreen;

現在，當從HomeScreen導航到DetailsScreen時，導航欄將顯示；當從DetailsScreen返回HomeScreen時，導航欄將隱藏。