rn-mobile-barcode-scanner

React Native Mobile Barcode Scanner

A barcode scanner component for React Native built on top of Dynamsoft Mobile Barcode SDK.

What You Should Know

• 
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Required Environment

• Node
• JDK
• Xcode
• Android Studio

Getting Started

Preparations

1. Create a new React Native project.

npx react-native init newBarcodeScanner

1. Open the project folder and find package.json. In the file, add the library to your project dependencies.

"dependencies": {
    "react": "16.9.0",
    "react-native": "0.61.1",
    "react-native-canvas": "^0.1.37",
    "rn-mobile-barcode-scanner": "^8.9.3",
    "react-native-webview": "^11.2.0"
}

1. In the command line, open your project folder and run yarn install.

yarn install

1. Return to the project folder. In App.js, use the following code to replace the original code.

import React from 'react';
import {
  StyleSheet,
  View,
  Text,
  TouchableOpacity,
  Dimensions
} from 'react-native';
import { DBRRNCamera } from 'rn-mobile-barcode-scanner';
import Canvas from 'react-native-canvas';
const deviceH = Dimensions.get('window').height
const deviceW = Dimensions.get('window').width
class CameraScreen extends React.Component {
  state = {
    license: '-- put your license here -- ',
    barcodeFormat: DBRRNCamera.Constants.DynamsoftBarcodeFormats.BarcodeFormat.ALL,
    barcodeFormat2: DBRRNCamera.Constants.DynamsoftBarcodeFormats.BarcodeFormat2.NULL,
    type: 'back',
    canDetectBarcode: false,
    barcodes: [{
      type: '',
      data: '',
      localizationResult: []
    }]
  };

  toggle = value => () => this.setState(prevState => ({ [value]: !prevState[value] }));

  barcodeRecognized = ({ barcodes }) => {
    this.setState({
      barcodes: barcodes
    });
  }

  handleCanvas = (canvas,barcodes) => {
    if (canvas) {
      canvas.width = deviceW
      canvas.height = deviceH
      const ctx = canvas.getContext('2d')
      ctx.fillStyle = 'green'
      ctx.lineWidth = 1
      ctx.globalAlpha = 0.5
      for(let res of this.state.barcodes){
        if (res.localizationResult.length > 0) {
          let loc = res.localizationResult
          // console.log('canvas', res.data)
          ctx.beginPath()
          ctx.moveTo(loc[0], loc[1])
          ctx.lineTo(loc[2], loc[3])
          ctx.lineTo(loc[4], loc[5])
          ctx.lineTo(loc[6], loc[7])
          ctx.fill()
          ctx.closePath()
          ctx.stroke()
        }
      }
    }else{
      // console.log('no canvas')
    }
  }

  renderBarcodes = () => (
    <React.Fragment key={this.state.barcodes.length}>
      {this.state.barcodes.map((barcodes)=><Canvas style={[styles.overlay]} ref={cvs=>this.handleCanvas(cvs,barcodes)} key={this.state.barcodes.length}/>)}
      <Text style={styles.textBlock}>{this.state.barcodes[0] ?'result:'+ this.state.barcodes[0].data:'result: null'}</Text>
    </React.Fragment>
  );

  renderCamera() {
    const { canDetectBarcode } = this.state;
    return (
        <DBRRNCamera
          ref={ref => {
            this.camera = ref;
          }}
          style={{
            flex: 1,
            justifyContent: 'space-between',
          }}
          type={this.state.type}
          license={this.state.license}
          androidCameraPermissionOptions={{
            title: 'Permission to use camera',
            message: 'We need your permission to use your camera',
            buttonPositive: 'Ok',
            buttonNegative: 'Cancel',
          }}
          onDynamsoftBarcodesReader={canDetectBarcode ? this.barcodeRecognized : null}
          barcodeFormat={this.state.barcodeFormat}
          barcodeFormat2={this.state.barcodeFormat2}
        >
          <View style={{height:'100%'}}>
            <View style={{height:'90%'}}>
            {!!canDetectBarcode && this.renderBarcodes()}
            </View>
            <View style={{ flexDirection: 'row', alignSelf: 'center' }}>
              <TouchableOpacity 
                onPress={this.toggle('canDetectBarcode')}
                style={[styles.flipButton, { flex: 0.5, alignSelf: 'center' }]}
              >
                <Text style={styles.flipText}>{!canDetectBarcode ? 'Decode' : 'Decoding'}</Text>
              </TouchableOpacity>
            </View>
          </View>
        </DBRRNCamera>
    );
  }

  render() {
    return (
    <View style={styles.container}>{this.renderCamera()}</View>
    )
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
  },
  flipButton: {
    flex: 0.3,
    height: 40,
    marginHorizontal: 2,
    borderRadius: 8,
    borderColor: 'white',
    borderWidth: 1,
    padding: 5,
    alignItems: 'center',
    justifyContent: 'center',
  },
  flipText: {
    color: 'white',
    fontSize: 15,
  },
  text: {
    padding: 10,
    borderWidth: 2,
    borderRadius: 2,
    position: 'absolute',
    borderColor: '#F00',
    justifyContent: 'center',
  },
  textBlock: {
    height: 'auto',
    color: 'white',
    textAlign: 'center',
    padding: 10,
    flexWrap: 'wrap'
  },
  overlay: {
    flex: 1,
  },
});

export default CameraScreen;

Build And Run Android

If you have completed the preparations, use the following command to run the project on your device.

npx react-native run-android

Build And Run iOS

1. Go to the ios folder in your project, run pod install

cd ios

pod install

1. Go back to the project folder and run the project.

cd ..

npx react-native run-ios