How to pass data to backend in React Native

Question

I'm trying to develop a barcode scanner app for IOS, now I have managed to create a scanner that can read data from barcodes, but not just reading the data, I also want to store the data into a database, I've explored some of the source code on the other side of my code.

Scanner.js

This is a scanner source that can already read data from barcodes

import React, { useState, useEffect,Component,onMount} from 'react';
import { Text,TextInput, View, StyleSheet, Button } from 'react-native';
import { BarCodeScanner } from 'expo-barcode-scanner';
import {useNavigation} from'@react-navigation/native';
import {StatusBar} from 'expo-status-bar';



 

  export default function Scanner () {
  
  const [hasPermission, setHasPermission] = useState(null);
  const [scanned, setScanned] = useState(false);
  const [userid, setText] = useState('Not yet scanned')
  const [currentDate, setCurrentDate] = useState('');
  const navigation = useNavigation();


  const askForCameraPermission = () => {
    (async () => {
      const { status } = await BarCodeScanner.requestPermissionsAsync();
      setHasPermission(status === 'granted');
    })()
  }

  // Request Camera Permission
  useEffect(() => {
    askForCameraPermission();
  }, []);

  useEffect(() => {
    var date = new Date().getDate(); //Current Date
    var month = new Date().getMonth() + 1; //Current Month
    var year = new Date().getFullYear(); //Current Year
    var hours = new Date().getHours(); //Current Hours
    var min = new Date().getMinutes(); //Current Minutes
    var sec = new Date().getSeconds(); //Current Seconds
    setCurrentDate(
      date + '/' + month + '/' + year 
      + ' ' + hours + ':' + min + ':' + sec
    );
  }, []);
  // What happens when we scan the bar code

  const handleBarCodeScanned = ({ type, data }) => {

   
    setScanned(true);
     
     
     setText(data )
     
   
  };
 
  // Check permissions and return the screens
  if (hasPermission === null) {
    return (
      <View style={styles.container}>
        <Text>Requesting for camera permission</Text>
      </View>)
  }
  if (hasPermission === false) {
    return (
      <View style={styles.container}>
        <Text style={{ margin: 10 }}>No access to camera</Text>
        <Button title={'Allow Camera'} onPress={() => askForCameraPermission()} />
      </View>)
  }
 
  // Return the View
  return (
     
    <View style={styles.container}>
      <View style={styles.barcodebox}>
        <BarCodeScanner
          onBarCodeScanned={scanned ? undefined : handleBarCodeScanned}
          style={{ height: 400, width: 400 }} />
      </View>
      
      <Text style={styles.maintext}>{userid + '\n'+currentDate}
    
      </Text>

      
      {
        scanned && <Button title={'Scan again?'} onPress={() => setScanned(false)} color='tomato' />
         
      }
     
      {
        scanned && <Button title={'OK'} onPress={()=> navigation.navigate('Home',{userid})} /> 
         
      }
    </View>
  );
}



const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
  maintext: {
    fontSize: 16,
    margin: 20,
  },
  barcodebox: {
    alignItems: 'center',
    justifyContent: 'center',
    height: 300,
    width: 300,
    overflow: 'hidden',
    borderRadius: 30,
    backgroundColor: 'tomato'
  }
});

After I explored ways to send data to the backend, it requires this kind of code, but how do I implement this code into my scanner.js? Hope everyone can help, thank you

export default class Scanner extends Component {

  constructor(props) {
    super(props);
    this.state = {userid: ''};
  }

  Register = () => {
    let userid = this.state.userid;
    

    
      let InsertAPIURL = "http://localhost/api/insert.php";

      let headers = {
        'Accept': 'application/json',
        'Content-Type': 'application/json'
      };

      let Data = {
        userid: userid,
       
      };

      fetch(InsertAPIURL, {
        method: 'POST',
        headers: headers,
        body: JSON.stringify(Data)
      })
      .then((response) =>response.json())
      .then((response)=>{
        alert(response[0].Message);
      })
      .catch((error) => {
        alert("Error"+error);
      })
    
  }
}

Answer 1

It was OK after I tried to implement it in scanner.js

import React, { useState, useEffect,Component,onMount} from 'react';
import { Text,TextInput, View, StyleSheet, Button } from 'react-native';
import { BarCodeScanner } from 'expo-barcode-scanner';
import {useNavigation} from'@react-navigation/native';
import {StatusBar} from 'expo-status-bar';



 

  export default function Scanner () {
  
  const [hasPermission, setHasPermission] = useState(null);
  const [scanned, setScanned] = useState(false);
  const [userid, setText] = useState('Not yet scanned')
  const [currentDate, setCurrentDate] = useState('');
  const navigation = useNavigation();


  const askForCameraPermission = () => {
    (async () => {
      const { status } = await BarCodeScanner.requestPermissionsAsync();
      setHasPermission(status === 'granted');
    })()
  }

  // Request Camera Permission
  useEffect(() => {
    askForCameraPermission();
  }, []);

  useEffect(() => {
    var date = new Date().getDate(); //Current Date
    var month = new Date().getMonth() + 1; //Current Month
    var year = new Date().getFullYear(); //Current Year
    var hours = new Date().getHours(); //Current Hours
    var min = new Date().getMinutes(); //Current Minutes
    var sec = new Date().getSeconds(); //Current Seconds
    setCurrentDate(
      date + '/' + month + '/' + year 
      + ' ' + hours + ':' + min + ':' + sec
    );
  }, []);
  // What happens when we scan the bar code

  const handleBarCodeScanned = ({ type, data }) => {

   
    setScanned(true);
     
     
     setText(data )
     
   
  };
  Register = () => {
    this.state={
        userid:''
    };
    let userid = this.state.userid;
    

    
      let InsertAPIURL = "https://127.0.0.1/api/insert.php";

      let headers = {
        'Accept': 'application/json',
        'Content-Type': 'application/json'
      };

      let Data = {
        userid: userid,
       
      };

      fetch(InsertAPIURL, {
        method: 'POST',
        headers: headers,
        body: JSON.stringify(Data)
      })
      .then((response) =>response.json())
      .then((response)=>{
        alert(response[0].Message);
      })
      .catch((error) => {
        alert("Eror"+error);
      })
    
  }

 
  // Check permissions and return the screens
  if (hasPermission === null) {
    return (
      
        Requesting for camera permission
      )
  }
  if (hasPermission === false) {
    return (
      
        No access to camera
         askForCameraPermission()} />
      )
  }
 
  // Return the View
  return (
     
    
      
        
      
      
      {userid + '\n'+currentDate}
    
      

      
      {
        scanned &&  setScanned(false)} color='tomato' />
         
      }
     
      {
        scanned &&  
         
      }
    
  );
}



const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
  maintext: {
    fontSize: 16,
    margin: 20,
  },
  barcodebox: {
    alignItems: 'center',
    justifyContent: 'center',
    height: 300,
    width: 300,
    overflow: 'hidden',
    borderRadius: 30,
    backgroundColor: 'tomato'
  }
});

Insert.php

 $Message);
    echo json_encode($Response);
?>

The error appears after I scan the barcode and click the "OK" button Type error: Network request failed