QR Codes

This is a free Skip Swift/Kotlin library project containing the following modules:

SkipQRCode

Installation

Add SkipQRCode as a dependency in your Package.swift:

dependencies: [
    .package(url: "https://source.skip.tools/skip-qrcode.git", "0.0.1"..<"2.0.0")
],
targets: [
    .target(
        name: "YourApp",
        dependencies: [
            .product(name: "SkipQRCode", package: "skip-qrcode")
        ]
    )
]

Quick Start

Basic Usage

import SwiftUI
import SkipQRCode

struct ContentView: View {
    @State private var showScanner = false
    @State private var scannedCode: String?

    var body: some View {
        VStack(spacing: 20) {
            Button("Scan QR Code") {
                showScanner = true
            }
            .buttonStyle(.borderedProminent)

            if let code = scannedCode {
                Text("Scanned: \(code)")
                    .font(.headline)
            }
        }
        .sheet(isPresented: $showScanner) {
            #if os(iOS)
            BarcodeScannerView { code in
                scannedCode = code
                showScanner = false
            }
            .ignoresSafeArea()
            #elseif os(Android)
            // Android scanner launches as a native activity
            Color.clear
                .onAppear {
                    showScanner = false
                    AndroidBarcodeScanner.scan { code in
                        if let code = code {
                            scannedCode = code
                        }
                    }
                }
            #endif
        }
    }
}

Advanced Example with Error Handling

import SwiftUI
import SkipQRCode

struct AdvancedScannerView: View {
    @State private var showScanner = false
    @State private var scannedCode: String?
    @State private var scanError: String?
    @State private var isScanning = false

    var body: some View {
        VStack(spacing: 20) {
            Text("QR Code Scanner")
                .font(.title)

            if let code = scannedCode {
                VStack(alignment: .leading, spacing: 8) {
                    Text("Scanned Code:")
                        .font(.caption)
                        .foregroundColor(.secondary)
                    Text(code)
                        .font(.body)
                        .padding()
                        .background(Color.gray.opacity(0.1))
                        .cornerRadius(8)
                }
                .padding()
            }

            if let error = scanError {
                Text("Error: \(error)")
                    .foregroundColor(.red)
                    .padding()
            }

            Button(action: startScanning) {
                HStack {
                    Image(systemName: "qrcode.viewfinder")
                    Text(isScanning ? "Scanning..." : "Scan QR Code")
                }
            }
            .buttonStyle(.borderedProminent)
            .disabled(isScanning)
        }
        .padding()
        .sheet(isPresented: $showScanner) {
            #if os(iOS)
            BarcodeScannerView { code in
                handleScanResult(code)
            }
            .ignoresSafeArea()
            #elseif os(Android)
            Color.clear
                .onAppear {
                    showScanner = false
                    performAndroidScan()
                }
            #endif
        }
    }

    private func startScanning() {
        scannedCode = nil
        scanError = nil
        isScanning = true
        showScanner = true
    }

    private func handleScanResult(_ code: String) {
        scannedCode = code
        showScanner = false
        isScanning = false
    }

    #if os(Android)
    private func performAndroidScan() {
        AndroidBarcodeScanner.scan { code in
            isScanning = false
            if let code = code {
                scannedCode = code
            } else {
                scanError = "Scan cancelled or failed"
            }
        }
    }
    #endif
}

Platform-Specific Behavior

iOS

Implementation: Uses VisionKit’s DataScannerViewController

Requires iOS 17.0+
Full-screen camera interface
Automatic barcode detection
Built-in guidance overlay
Pinch-to-zoom support
High frame rate tracking

Permissions: Add camera usage description to your Info.plist:

<key>NSCameraUsageDescription</key>
<string>We need camera access to scan QR codes and barcodes</string>

Android

Implementation: Uses Google ML Kit with CameraX

Requires Android API 24+
Native activity-based scanner
ML Kit barcode detection
Torch/flashlight control
Portrait orientation

Permissions: Automatically merged from the package’s AndroidManifest.xml:

android.permission.CAMERA
Camera hardware features (optional)

Activities: Scanner activities are automatically registered:

skip.qrcode.MLKitScanActivity - Main scanner with camera
skip.qrcode.ScanHostActivity - Activity launcher/bridge

API Reference

`AndroidBarcodeScanner`

A utility struct for launching the Android scanner.

public struct AndroidBarcodeScanner {
    public static func scan(completion: @escaping @Sendable (String?) -> Void)
}

Parameters:

completion: Async callback invoked when scanning completes. Receives:
- The scanned barcode string if successful
- nil if the scan was cancelled or failed

Usage:

AndroidBarcodeScanner.scan { result in
    if let barcode = result {
        print("Scanned: \(barcode)")
    } else {
        print("Scan cancelled or failed")
    }
}

Supported Barcode Types

SkipQRCode supports all common 1D and 2D barcode formats:

2D Codes: QR Code, Data Matrix, Aztec, PDF417
1D Codes: UPC-A, UPC-E, EAN-8, EAN-13
Other: Code 39, Code 93, Code 128, ITF, Codabar
Specialized: Driver’s License, Calendar Events, Contact Info

Architecture

SkipQRCode is a transpiled Skip package with bridging support, which means:

✅ iOS: Direct Swift → VisionKit (native iOS framework)
✅ Android: Swift → Transpiled Kotlin → ML Kit + CameraX
✅ Bridging: Automatically bridges to native SkipFuse apps
✅ Platform Optimized: Uses best-in-class libraries for each platform
✅ Zero Setup: Import once, works on both platforms

Component Overview

iOS Side:
  SwiftUI → VisionKit DataScannerViewController

Android Side (Transpiled):
  Swift → AndroidBarcodeScanner.swift
    ↓ (transpiles to)
  Kotlin → ScanHostActivity → MLKitScanActivity
            (activity trampoline)  (CameraX + ML Kit scanner)

How It Works

On iOS: Uses Apple’s VisionKit for native barcode scanning
On Android:
- Swift code transpiles to Kotlin
- Launches native Android Activities with ML Kit
- Camera preview rendered programmatically (no XML resources)
- Results passed back via polling mechanism

Requirements

iOS: 17.0 or later
Android: API 24 (Android 7.0) or later
Skip: 1.6.27 or later
Xcode: 15.0 or later

Building

This project uses the Skip plugin with native compilation mode.

Install Skip using Homebrew ↗:

brew install skiptools/skip/skip

Build the package:

swift build

Testing

Run tests using:

swift test

For parity testing across platforms:

skip test

Troubleshooting

iOS

Scanner doesn’t appear:

Ensure you’re running on iOS 17.0 or later
Check that NSCameraUsageDescription is in your Info.plist
Verify camera permissions are granted

Scanner shows but doesn’t scan:

Check that DataScannerViewController.isSupported returns true
Ensure good lighting conditions
Try different barcode types

Android

Scanner crashes on launch:

Verify all dependencies are properly resolved
Check that camera permissions are declared in manifest
Ensure device has a working camera

Scanned results not returning:

Check LogCat for error messages (tag: MLKitScanActivity, ScanHostActivity)
Ensure ML Kit dependencies are included
Verify network connectivity (ML Kit may download models)

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Development Setup

Clone the repository
Install Skip: brew install skiptools/skip/skip
Open in Xcode or your preferred IDE
Make your changes
Run tests: swift test or skip test
Submit a PR

Credits

Built with Skip - Swift for iOS and Android

Technologies Used:

iOS: VisionKit, SwiftUI
Android: ML Kit, CameraX, Kotlin, Jetpack Compose