Barcode Scanning in Android Apps

Barcode scanning is one of the most potentially useful resources you will come across on the Android platform. The ZXing (Zebra Crossing) project is bar far the easiest and most effective way to implement barcode scanning for most development purposes. Since the project is open source, you can either use the code within it to implement your own custom scanning functions or can access the library classes via Intent, leaving the details up to the ZXing classes.

ZXing can scan numerous barcode formats in use on a variety of products, including EAN/ ISBN, UPC, QR codes, Data Matrix, Aztec and more. The resource is implemented in Java, with Android-specific classes available for quick use in your own projects.

Usage

For a detailed introduction to using barcode scanning in Android apps, see this tutorial I wrote for Mobiletuts+: Create a Barcode Reader and this series on creating a book scanner app for more of a real-world example: Create a Book Scanning App. For a comprehensive reference, see the ZXing docs: Scanning Via Intent.

The simplest way to include scanning functions in your apps is by Intent. You simply copy the Intent Integrator and Intent Result classes into your app and call on them in your own classes.

To use the ZXing integration classes in your app, import them to the Activity class you want to access them in, for example the following if you use the default package names:

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;

You can then launch the scanner in your Activity class as follows:

IntentIntegrator zxingIntegrator = new IntentIntegrator(this);
zxingIntegrator.initiateScan();

If the user does not have the ZXing barcode scanner installed on their device, they will be prompted to download it from Google Play at this point, so you don't have to carry out any checking of your own. When you initiate a scan, you can optionally pass a parameter indicating the types of barcode you want to scan - the parameter should be a Collection of Strings.

You can then retrieve the results of the user's scanning operation inside the onActivityResult method for your class:

IntentResult scannedResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);

The Intent Result object will now provide access to the content and format of the returned scan data if there is any:

scannedResult.getContents();
scannedResult.getFormatName();

Options

While using the integration classes is by far the simplest way to utilise the ZXing functionality, there may be times when you need to implement your own bespoke scanning functions. If so, you can download the source code. It's probably only advisable to do this if you have no other option, since using the integration classes gives your app access to the continual updates within the ZXing app without you having to update your own code.

Applications

There are lots of potential applications of barcode scanning in Android, from inventory and warehouse functions to shopping apps. Your apps need to respond to the data within a barcode in a relevant way, so your code must examine the scan results before attempting to use them in further processing, for example opening a URL in the browser.

As usual, Stack Overflow has the answers to lots of common questions and problems with ZXing.