如何使用php mysql解决React Native LogOut问题

如何解决如何使用php mysql解决React Native LogOut问题

This is error show then is used this props.screenProps.onLogout(); for logout *这是错误显示TypeError：undefined不是对象（正在评估“ props.screenProps”） 所以请我为我做些什么 我试图编写php脚本进行登录和注销。登录工作正常，但问题是我退出后按了后退按钮时出现了一些错误 * App.js

import React from "react";
import {View,AsyncStorage,} from "react-native";
import LoginView from './components/LoginView';
import HomeView from './components/HomeView';

export default class App extends React.Component {

  constructor(props) {
    super(props);
    this.state = {
        is_logged_in: false,};
    AsyncStorage.getItem('fam_user_data')
    .then((item) => {
      if (item != null) {
          this.setState({ 'is_logged_in': true });
      }
   });
}

  onLogout() {
    AsyncStorage.removeItem('fam_user_data');
    this.setState({is_logged_in: false});
}  

render() {
  if (this.state.is_logged_in){
      return (
          <View style={{flex: 1}}>
              <HomeView screenProps={{onLogout: this.onLogout.bind(this)}} />
          </View>
      );
  } else {
      return (
          <View style={{flex: 1}}>
              <LoginView loginSccess={() => this.setState({is_logged_in: true})} />  
          </View>
      );
  }
}
}

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import React from "react";
import {
  View,Text,TouchableOpacity,Image,Alert,SafeAreaView,ScrollView
} from "react-native";
import { NavigationContainer } from '@react-navigation/native';
import { createDrawerNavigator,DrawerContentScrollView,DrawerItemList,DrawerItem } from '@react-navigation/drawer';
import { createStackNavigator } from '@react-navigation/stack';
import EditHome from '.././pages/EditHome';
import EditAbout from '.././pages/EditAbout';

  
const CustomDrawerComponent = (props) => (
  <SafeAreaView style={{flex: 1}}>
    <View style={{height: 150,alignItems: 'center',justifyContent: 'center'}}>
        <Image
          source={require('../assets/logo.png')}
          resizeMode={'cover'}
          style={{ width: 128,height: 128} }
        />      
    </View>
    <ScrollView>
      <DrawerItemList {...props} />
    </ScrollView>
    <TouchableOpacity onPress={()=>
      Alert.alert(
          'Log out','Do you want to logout?',[
            {text: 'Cancel',onPress: () => {return null}},{text: 'Confirm',onPress: () => {
              props.screenProps.onLogout();
            
            }},],{ cancelable: false }
       )  
    }>
        <Text style={{margin: 16}}>Logout</Text>
    </TouchableOpacity>
    </SafeAreaView>
)
  
  const Drawer = createDrawerNavigator();
  const Stack = createStackNavigator();

  function MyStack(){
    return(
      <Stack.Navigator initialRouteName="Home">
        <Stack.Screen name="EditAbout" component={EditAbout} options={{ title: 'Edit Home' }}/>
        <Stack.Screen name="EditHome" component={EditHome} options={{ title: 'Edit Home' }}/>
      </Stack.Navigator>
    );
  }
  function MyDrawer() {
    return (
      <Drawer.Navigator drawerContent={props => <CustomDrawerComponent {...props}/>} 
        drawerStyle={{
        backgroundColor: '#fff',width: 200,}}
      > 
        <Drawer.Screen name="Edit Home" component={EditHome} />
        <Drawer.Screen name="Edit About" component={EditAbout} />
      </Drawer.Navigator>
    );
  }
  
  export default function App() {
    return (
      <NavigationContainer>
        <MyDrawer/>
      </NavigationContainer>
    );
  }