react-native-barcode-scanner-google

Author's notes

  1. This is not the exact version you install using npm i react-native-barcode-scanner-google. That version was uploaded based on this code, by a third party. Use at your own risk!

  2. As of September 2019, this repo is no longer being maintained. Due to its simplicitity it should still work great though so keep using it by all means!

  3. Look into https://github.com/react-native-community/react-native-camera for new projects if the bigger package/dependency tree isn't a problem. The latest version includes an implementation of Google's Vision API via this library. Enjoy!

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:

Note that this barcode scanner doesn't ship with a fancy overlay to display a scanning interface to the user. It's just a fast scanner view that shows the camera stream, ontop of which you can overlay your own UI.

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:

1.

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

2.

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,
    TorchMode,
    CameraFillMode,
    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 */}
                    torchMode={TorchMode.ON /* could be the default OFF */}
                    cameraFillMode={
                        CameraFillMode.COVER /* could also be FIT */
                    }
                    barcodeType={
                        BarcodeType.CODE_128 |
                        BarcodeType.EAN_13 |
                        BarcodeType.EAN_8 /* replace with ALL for all alternatives */
                    }
                />
            </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)

focusMode

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

Possible values for this prop are:

torchMode

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

Possible values for this prop are:

cameraFillMode

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

Possible values for this prop are:

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:

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