QR Mobile Vision

Reading QR codes and other barcodes using Google's Mobile Vision API.

This plugin uses Android & iOS native APIs for reading images from the device's camera. It then pipes these images both to the Mobile Vision API which detects barcodes/qrcodes etc, outputs a preview image to be shown on a flutter texture.

The plugin includes a widget which performs all needed transformations on the camera output to show within the defined area.

Usage

See the example for how to use this plugin; it is the best resource available as it shows the plugin in use. However, these are the steps you need to take to use this plugin.

First, figure out the area that you want the camera preview to be shown in. This is important as the preview needs to have a constrained size or it won't be able to build. This is required due to the complex nature of the transforms needed to get the camera preview to show correctly on both iOS and Android, while still working with the screen rotated etc.

It may be possible to get the camera preview to work without putting it in a SizedBox or Container, but the recommended way is to put it in a SizedBox or Container.

You then need to include the package and instantiate the camera.

import 'package:qr_mobile_vision/qr_camera.dart';

...

new SizedBox(
  width: 300.0,
  height: 600.0,
  child: new QrCamera(
    qrCodeCallback: (code) {
      ...
    },
  ),
)

The QrCodeCallback can do anything you'd like, and wil keep receiving QR codes until the camera is stopped.

There are also 2 optional parameters to QrCamera. The first is fit, which takes as parameter the flutter BoxFit. Setting this to differnet values should get the preview image to fit in different ways, but only BoxFit = cover has been tested.

The other is notStartedBuilder, which is a callback that must return a widget if defined. This should build whatever you want to show up while the camera is loading (which can take from milliseconds to seconds depending on the device).

Contributions

Anyone wanting to contribute to this project is very welcome to! I'll take a look at PR's as soon as I can, and any bug reports are appreciated. I've only a few devices on which to test this so feedback about other devices is appreciated as well.

This has been tested on:

  • Nexus 5x
  • Nexus 4
  • Alcatel Idol X Plus
  • Essential Phone
  • iPhone 6

Libraries

qr_camera
qr_mobile_vision