I’m using React Native Expo. Currently i’m trying to make an application which uses a barcodescanner for scanning QR-code objects. I’ve implemented a turn camera button for the front or back camera but when i press the button it does nothing only when i switch from one screen to the other. I think there is something wrong with refreshing the screen immediately but i’ve no clue of how i should solve this problem
Code:
import React, { useEffect, useState, useLayoutEffect } from 'react';
import { StyleSheet, Text, View, Button, Alert, ActivityIndicator, Pressable } from 'react-native';
import { globalStyles } from '../styles/global';
// import { Camera, BarCodeScanningResult } from 'expo-camera';
import { BarCodeScanner } from 'expo-barcode-scanner';
import BarcodeMask from 'react-native-barcode-mask';
import { useIsFocused, useNavigation } from '@react-navigation/native';
import CustomButton from '../components/CustomButton';
import Icon from 'react-native-vector-icons/MaterialCommunityIcons';
export function ShowLoading(){
return(
<View style={styles.loader}><ActivityIndicator size="large" color='white'/></View>
)
}
export default function Scan(){
const navigation = useNavigation()
const [hasPermission, setHasPermission] = useState(null);
const [scanned, setScanned] = useState(false);
const [loading, setLoading] = useState(false);
const [type, setType] = useState(BarCodeScanner.Constants.Type.back);
const isFocused = useIsFocused()
useEffect(() => {
(async () => {
const {status} = await BarCodeScanner.requestPermissionsAsync();
setHasPermission(status === 'granted');
})();
}, []);
// useEffect(() => {
// if(loading){
// setLoading(true)
// } else {
// setLoading(false)
// }
// },[loading])
const initScanner = async() => {
const {status} = await BarCodeScanner.requestPermissionsAsync();
setHasPermission(status === 'granted');
}
const handleNavigation = async() => {
setScanned(false)
navigation.navigate('Oefening')
}
const handleNo = () => {
setScanned(false)
}
const handleBarCodeScanned = ({ type, data }) => {
setScanned(true)
setLoading(true)
setTimeout(() => { Alert.alert(
'QR-Code gevonden',
`QR-Code met type ${type} en data ${data} is gescand, wilt u verder gaan?`,
[
{
text: "Nee",
onPress: () => handleNo(),
},
{
text: "Ja",
onPress: () => handleNavigation(),
}
]
), setLoading(false)}, 1000)
}
if (hasPermission === null) {
return <View style={styles.permissionWrapper}>
<Text style={styles.permissionText}>Een moment geduld..</Text>
<ActivityIndicator size='large' color='#1f69b1'></ActivityIndicator>
</View>;
}
if (hasPermission === false) {
return <Text>Geen toegang tot uw camera!</Text>;
}
return (
<View style={{flex: 1, flexDirection: 'column', justifyContent: 'flex-end'}}>
{loading? (<View style={styles.loader}><ActivityIndicator size='large' color='#1f69b1'></ActivityIndicator></View>
) : (
isFocused &&
<BarCodeScanner
onBarCodeScanned={scanned ? undefined : handleBarCodeScanned}
style={StyleSheet.absoluteFillObject}
type={type}
>
<View style={styles.topOptions}>
<View style={styles.cameraRotateWrapper}>
<Pressable style={styles.cameraRotate}
onPress={() => {
setType(
type === BarCodeScanner.Constants.Type.back
? BarCodeScanner.Constants.Type.front
: BarCodeScanner.Constants.Type.back
);
}}
>
<Icon name='rotate-3d-variant' size={40} color={'white'}></Icon>
</Pressable>
</View>
</View>
<BarcodeMask edgeColor={'#62B1F6'} showAnimatedLine={true}/>
</BarCodeScanner>)}
{scanned? <View style={styles.searchTextWrapper}><Text style={styles.searchText}>Gevonden!</Text></View> : <View style={styles.searchTextWrapper}><Text style={styles.searchText}>Zoeken naar QR-Code.... </Text></View>}
{/* {scanned? <Button title={'Opnieuw scannen'} onPress={() => setScanned(false)} /> : null} */}
<View style={styles.bottomOptions}>
<CustomButton textValue="Herladen" onPress={initScanner}></CustomButton>
</View>
</View>
)
}
const styles = StyleSheet.create({
loader: {
justifyContent: "center",
alignItems: 'center',
},
permissionWrapper: {
justifyContent: 'center',
alignItems:'center',
margin: 15,
},
permissionText: {
fontSize: 16,
fontWeight: 'bold',
},
topOptions: {
marginTop: 20,
justifyContent: 'space-between',
marginHorizontal: '10%'
},
searchTextWrapper: {
},
searchText: {
color: 'white',
fontSize: 18,
textAlign: 'center',
},
cameraRotateWrapper: {
width: 50,
height: 50,
},
cameraRotate: {
justifyContent: 'center',
alignItems: 'center',
borderWidth: 1,
borderColor: "white",
backgroundColor: '#1f69b1',
borderRadius: 10,
},
bottomOptions: {
marginHorizontal: '10%',
marginBottom: 10,
},
})