EXPO应用程序在iOS上出现在前面时会闪烁，但Android没问题。 它是由 EXPO 自动创建的（反应导航）

Question

I have created my app with Expo(React Navigation 5.0) and changed "createBottomTabNavigator" to "createMaterialBottomTabNavigator". But When it is at front as soon as it was at back, it is blink.

This is the captured screen of terminal for my initiating app. creating my app by EXPO

This is the code which is only changed by me.

import { createMaterialBottomTabNavigator } from '@react-navigation/material-bottom-tabs';


const BottomTab = createMaterialBottomTabNavigator<BottomTabParamList>();

The rest of code is automatically made by "expo init my-app"

This is App.tsx

import { StatusBar } from 'expo-status-bar';
import React from 'react';
import { SafeAreaProvider } from 'react-native-safe-area-context';
import useCachedResources from './hooks/useCachedResources';
import useColorScheme from './hooks/useColorScheme';
import Navigation from './navigation';

export default function App() {
  const isLoadingComplete = useCachedResources();
  const colorScheme = useColorScheme();

  if (!isLoadingComplete) {
    return null;
  } else {
    return (
      <SafeAreaProvider>
        <Navigation colorScheme={colorScheme} />
        <StatusBar />
      </SafeAreaProvider>
    );
 }

}

and this is index.tsx

import { NavigationContainer, DefaultTheme, DarkTheme } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import * as React from 'react';
import { ColorSchemeName } from 'react-native';
import NotFoundScreen from '../screens/NotFoundScreen';
import { RootStackParamList } from '../types';
import BottomTabNavigator from './BottomTabNavigator';
import LinkingConfiguration from './LinkingConfiguration';

// If you are not familiar with React Navigation, we recommend going through the
// "Fundamentals" guide: https://reactnavigation.org/docs/getting-started
export default function Navigation({ colorScheme }: { colorScheme: ColorSchemeName }) {
  return (
    <NavigationContainer
      linking={LinkingConfiguration}
      theme={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
     <RootNavigator />
    </NavigationContainer>
  );
}

// A root stack navigator is often used for displaying modals on top of all other content
// Read more here: https://reactnavigation.org/docs/modal
const Stack = createStackNavigator<RootStackParamList>();

function RootNavigator() {
  return (
    <Stack.Navigator screenOptions={{ headerShown: false }}>
      <Stack.Screen name="Root" component={BottomTabNavigator} />
      <Stack.Screen name="NotFound" component={NotFoundScreen} options={{ title: 'Oops!' }} />
    </Stack.Navigator>
  );
}

This is blinking captured video

I hope anyone can help me

Answer 1

It is a known bug in react-native. https://github.com/facebook/react-native/issues/28525

Try to replace useColorScheme hook (hooks/useColorScheme.ts) with the following code:

 import { Appearance, ColorSchemeName } from 'react-native'; import { useEffect, useRef, useState } from 'react'; export default function useColorScheme(delay = 500): NonNullable<ColorSchemeName> { const [colorScheme, setColorScheme] = useState(Appearance.getColorScheme()); let timeout = useRef<NodeJS.Timeout | null>(null).current; useEffect(() => { Appearance.addChangeListener(onColorSchemeChange); return () => { resetCurrentTimeout(); Appearance.removeChangeListener(onColorSchemeChange); }; }, []); function onColorSchemeChange(preferences: Appearance.AppearancePreferences) { resetCurrentTimeout(); timeout = setTimeout(() => { setColorScheme(preferences.colorScheme); }, delay); } function resetCurrentTimeout() { if (timeout) { clearTimeout(timeout); } } return colorScheme as NonNullable<ColorSchemeName>; }