mob_scanner

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QR code / barcode scanner for apps built with Mob — extracted from mob core as a plugin. Opens a full-screen camera preview; when a code is detected the view dismisses automatically and the result lands in handle_info.

iOS: AVCaptureMetadataOutput. Android: CameraX + ML Kit BarcodeScanning in a plugin-owned full-screen activity.

Installation

Requires mob_camera activated alongside — the :camera runtime permission (and the iOS NSCameraUsageDescription plist key) is owned by mob_camera:

# mix.exs
{:mob_scanner, "~> 0.1"},
{:mob_camera,  "~> 0.1"}

# mob.exs
config :mob, :plugins, [:mob_camera, :mob_scanner]

Request :camera via Mob.Permissions.request(socket, :camera) before scanning.

Usage

socket = MobScanner.scan(socket, formats: [:qr])

def handle_info({:scan, :result, %{type: :qr, value: value}}, socket), do: ...
def handle_info({:scan, :cancelled}, socket), do: ...
# iOS additionally delivers {:scan, :not_available} when no camera input can be opened

Formats: :qr, :ean13, :ean8, :code128, :code39, :upca, :upce, :pdf417, :aztec, :data_matrix.

Host app requirements

AndroidManifest.xml must declare the scanner activity inside <application> (mob_new-generated apps already include it):

<activity android:name="io.mob.scanner.MobScannerActivity"
          android:exported="false"
          android:theme="@style/Theme.AppCompat.NoActionBar" />

Without the declaration the app builds and boots fine, then throws ActivityNotFoundException at first scan. The AppCompat theme is required — MobScannerActivity extends AppCompatActivity and throws IllegalStateException at setContentView under a non-AppCompat theme.

Limits

  • The formats: option is currently ignored by both native sides (core parity: iOS hardcodes its metadata object types, Android scans all ML Kit formats). It's encoded and passed through, so honoring it later is a non-breaking change.

License

MIT