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qrscan #

One-shot Flutter QR / barcode plugin: open camera, first decode, return a string, close. Also album / path / bytes decode, and QR PNG generation.

This is not an embedded camera widget. If you need a preview, scan window, overlay, torch API, or continuous scan, use mobile_scanner — that race is already over.

This is not a hardware gun. Keyboard wedge → a TextField. OEM broadcast PDA → pda_scanner. Do not open the camera for those.

• Android CameraX 1.4 + ZXing 3.5.3 (QR, Code 128/39/93, EAN, UPC, ITF, Data Matrix, PDF417, Aztec, Codabar)
• iOS AVFoundation + Vision
• Dart 3 / Flutter 3.10+ / Android embedding v2
• Public Dart API is the same five functions as 0.3.x

Install #

dependencies:
  qrscan: ^1.0.0

Dart 3 / Flutter 3.10+. Git pin if you need a commit:

dependencies:
  qrscan:
    git:
      url: https://github.com/wu9007/qrcode_scanner.git
      ref: v1.0.0

Android #

minSdk 21. Camera permission is requested when scan() runs, not at install. Do not add storage permissions — album picking uses the system picker.

Host MainActivity must be embedding v2 (FlutterActivity).

The scanner activity follows the device orientation. It does not lock portrait. If the user has system rotation lock on, the scanner stays put.

iOS #

Add to ios/Runner/Info.plist:

<key>NSCameraUsageDescription</key>
<string>Scan QR codes and barcodes</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>Read a code from a photo</string>

Minimum iOS 12.

Landscape on iOS only works if the host app already lists landscape in UISupportedInterfaceOrientations. A plugin cannot override that plist.

Usage #

import 'package:qrscan/qrscan.dart' as scanner;

String? cameraScanResult = await scanner.scan();
String? photoScanResult = await scanner.scanPhoto();
String? fromPath = await scanner.scanPath(path);
String? fromBytes = await scanner.scanBytes(bytes);
Uint8List qrPng = await scanner.generateBarCode('https://github.com/wu9007/qrcode_scanner');

That is the whole API. There is no widget, no scan-area parameter, no front-camera switch, no stream, no format filter.

Errors from scan() #

Cancel is null. Real failures throw PlatformException:

Decoder #

QR is tried first (with TRY_HARDER), then other 2D, then 1D. A dense QR is not returned as UPC-E. There is no formats: argument — if you must restrict symbologies, use mobile_scanner.

Latin-1 QR (ISO-8859-1, no ECI) is not forced to UTF-8. Byte segments that are valid UTF-8 with high bits stay UTF-8 (typical Chinese QR). generateBarCode writes UTF-8.

Decoder order is covered by tool/decoder-harness (30 fixtures in CI).

When not to use this #

Three mutually exclusive paths: camera one-shot (this plugin) · OEM broadcast (pda_scanner) · HID keyboard (nothing). Mixing them is how field apps “break”.

0.3 → 0.4 #

Public Dart API is unchanged. The two new error constants are optional.

License #

MIT. Created by Shusheng.