react-native-barcode-scanner-google

react-native-barcode-scanner-google

Very fast barcode scanner view for React Native applications. Only for Android. Use something like react-native-camera for iOS. The postfix -google is added since the native implementation is based on Google's Barcode API: https://developers.google.com/vision/barcodes-overview

Compared to other barcode scanners for Android that don't rely on Google's Barcode API, this implementation should prove to be:

• Faster
• More accurate
• More convenient (supports scanning in any direction)

Instructions

To include the latest version (1.3.0) react-native-barcode-scanner-google in your project, run the following terminal commands in your React Native project root folder:

npm install git+https://github.com/spyworldxp/react-native-barcode-scanner-google.git#v1.3.0 --save

react-native link react-native-barcode-scanner-google

Simple usage example

Example index.android.js of an app named BarcodeApp.

import React, { Component } from 'react';
import { AppRegistry, StyleSheet, Text, View, Alert } from 'react-native';
import BarcodeScanner from 'react-native-barcode-scanner-google';


export default class BarcodeApp extends Component {
  render() {
    return (
      <View style={{flex: 1}}>
          <BarcodeScanner
              style={{flex: 1}}
              onBarcodeRead={({data, type}) => {
                  // handle your scanned barcodes here!
                  // as an example, we show an alert:
                  Alert.alert(`Barcode '${data}' of type '${type}' was scanned.`);
              }}
          />
      </View>
    );
  }
}

AppRegistry.registerComponent('BarcodeApp', () => BarcodeApp);

Advanced usage example (all properties used)

Note: even though they're not used in this example, notice how we import the functions pauseScanner and resumeScanner. These can be used in complex UIs to start or stop the camera stream to the scanner. Read more about how they work in Properties down below.

import React, { Component } from 'react';
import { AppRegistry, StyleSheet, Text, View, Alert } from 'react-native';

import BarcodeScanner, { Exception, FocusMode, FlashMode, BarcodeType, pauseScanner, resumeScanner } from 'react-native-barcode-scanner-google';

export default class BarcodeApp extends Component {
  render() {
    return (
      <View style={{flex: 1}}>
          <BarcodeScanner
              style={{flex: 1}}
              onBarcodeRead={({data, type}) => {
                  // handle your scanned barcodes here!
                  // as an example, we show an alert:
                  Alert.alert(`Barcode '${data}' of type '${type}' was scanned.`);
              }}
              onException={exceptionKey => {
                  // check instructions on Github for a more detailed overview of these exceptions.
                  switch (exceptionKey) {
                      case Exception.NO_PLAY_SERVICES:
                          // tell the user they need to update Google Play Services
                      case Exception.LOW_STORAGE:
                          // tell the user their device doesn't have enough storage to fit the barcode scanning magic
                      case Exception.NOT_OPERATIONAL:
                          // Google's barcode magic is being downloaded, but is not yet operational.
                      default: break;
                  }
              }}
              focusMode={FocusMode.AUTO /* could also be TAP or FIXED */}
              barcodeType={BarcodeType.CODE_128 | BarcodeType.EAN_13 | BarcodeType.EAN_8 /* replace with ALL for all alternatives */}
              flashMode={FlashMode.OFF /* 0 is OFF or 1 is TORCH  */}
              precisionMode={PrecisionMode.RESPONSIVE /* could be the default PRECISE */ }
          />
      </View>
    );
  }
}

AppRegistry.registerComponent('BarcodeApp', () => BarcodeApp);

Properties

barcodeTypes

Bitmask of the different barcode formats you want to scan for. For instance BarcodeType.QR_CODE | BarcodeType.EAN_8 | BarcodeType.EAN_13 or just BarcodeType.ALL to search for all barcodes supported. Use import { BarcodeType } from 'react-native-barcode-scanner-google'; to import the BarcodeType object.

All possible values are: (Bitwise OR can be used to select multiple formats)

• BarcodeType.ALL (default)
• BarcodeType.CODE_128
• BarcodeType.CODE_39
• BarcodeType.CODE_93
• BarcodeType.CODABAR
• BarcodeType.DATA_MATRIX
• BarcodeType.EAN_13
• BarcodeType.EAN_8
• BarcodeType.ITF
• BarcodeType.QR_CODE
• BarcodeType.UPC_A
• BarcodeType.UPC_E
• BarcodeType.PDF417
• BarcodeType.AZTEC

---

focusMode

Use import { FocusMode } from 'react-native-barcode-scanner-google'; to import the FocusMode object.

Possible values for this prop are:

• FocusMode.AUTO: Continuous automatic focus. (default)
• FocusMode.TAP: Tap-to-focus
• FocusMode.FIXED: Fixed focus

---

precisionMode

Use import { PrecisionMode } from 'react-native-barcode-scanner-google'; to import the PrecisionMode object.

Possible values for this prop are:

• PrecisionMode.PRECISE: Scans on higher resolution but displays preview at 15 FPS. (default)
• PrecisionMode.RESPONSIVE: Scans on lower resolution but displays preview at 30 FPS giving the more responsive feel.

---

flashMode

Use import { FlashMode } from 'react-native-barcode-scanner-google'; to import the FlashMode object.

Possible values for this prop are:

• FlashMode.OFF: Disables flashlight. (default)
• FlashMode.TORCH: Enables flashlight.

---

onBarcodeRead(): function(obj: Object)

Alias onBarCodeRead(). Callback function that will be called every time the scanner detects a new barcode. The parameter obj has the shape:

{
    "data": "12345678", // the barcode itself
    "type": "EAN_13" // the format of data. will be one of the supported formats, or "UNKNOWN_FORMAT"
}

---

onException: function(key: String)

Google's Barcode API requires some native code to be downloaded to the device behind the scenes for it to work. This makes it possible to always keep the latest barcode scanner featurability available, but also comes with a few drawbacks. Namely, the barcode scanning features might not be available yet when the user opens the app to scan. This callback allows for those exceptions to be handled on the JS side. Use import { Exception } from 'react-native-barcode-scanner-google'; to import the Exception object.

Possible values for the parameter key are:

• Exception.NO_PLAY_SERVICES: Occurs when the user doesn't have the latest version of Google Play Services. If this is the case, ask the user to update Play Services.
• Exception.LOW_STORAGE: Occurs when the native setup couldn't be completed because the user's device had low storage.
• Exception.NOT_OPERATIONAL: Occurs when the user did have enough storage, but opened the app before downloads were completed. Encourage the user to wait a bit or turn on their internet if this happens.

If any of the above events occur, the scanner will default to show a black screen instead of the camera preview.

---

Utility functions resumeScanner and pauseScanner: function()

Methods that can be used to pause/resume the camera stream of the barcode scanner JS-side. Most often you will not need these at all! They're meant to give advanced users more control over the scanner view. Use import { resumeScanner, pauseScanner } from 'react-native-barcode-scanner-google'; to import these utility functions.

Both methods return a Promise object and are used similarly. Example usage of resumeScanner:

    resumeScanner()
      .then(() => {
        // do something after the scanner (camera) stream was resumed.
      })
      .catch(e => {
        // Print error if scanner stream could not be resumed.
        console.log(e);
      });

---

License

MIT License