working react native bar-code scanner

react native barcode scanner

//for android made following changes 
//1)AndroidManifest.xml 
//<uses-permission android:name="android.permission.CAMERA" />
//2) Android/app/build.gradle
//defaultConfig {
// missingDimensionStrategy 'react-native-camera', 'general' // <--- insert this line
//}
import React, {Component} from 'react';
import {
  Text,
  View,
  StyleSheet,
  Alert,
  TouchableOpacity,
  Image,
  Dimensions,
} from 'react-native';
import Icon from 'react-native-vector-icons/MaterialCommunityIcons';
import {RNCamera} from 'react-native-camera';
export default class BarcodeScan extends Component {
  constructor(props) {
    super(props);
    this.handleTourch = this.handleTourch.bind(this);
    this.state = {
      torchOn: false,
      height: Dimensions.get('window').height,
    };
  }
  onBarCodeRead = e => {
    Alert.alert('Barcode value is' + e.data, 'Barcode type is' + e.type);
  };
  render() {
    return (
      <View style={styles.container}>
        <RNCamera
          style={{
            flex: 1,
            justifyContent: 'flex-end',
            alignItems: 'center',
            height: 0.9 * this.state.height,
          }}
          torchMode={
            this.state.torchOn
              ? RNCamera.Constants.FlashMode.on
              : RNCamera.Constants.FlashMode.off
          }
          onBarCodeRead={this.onBarCodeRead}
          ref={cam => (this.camera = cam)}>
          <Text
            style={{
              backgroundColor: 'white',
            }}>
            BARCODE SCANNER
          </Text>
        </RNCamera>
        <View style={styles.bottomOverlay}>
          <TouchableOpacity
            onPress={() => this.handleTourch(this.state.torchOn)}>
            <Text>
              <Icon
                name={this.state.torchOn === true ? 'celtic-cross' : 'star'}
                size={10}
                color="#900"
              />
            </Text>
          </TouchableOpacity>
        </View>
      </View>
    );
  }
  handleTourch(value) {
    if (value === true) {
      this.setState({torchOn: false});
    } else {
      this.setState({torchOn: true});
    }
  }
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: 'row',
  },
  cameraIcon: {
    margin: 5,
    height: 40,
    width: 40,
  },
  bottomOverlay: {
    position: 'absolute',
    width: '100%',
    flex: 20,
    flexDirection: 'row',
    justifyContent: 'space-between',
  },
});