compose 二维码扫描qrcode

扫描预览

@Composable
fun ScannerContent(modifier: Modifier, onScan: (String) -> Unit) {
    val lifecycleOwner = LocalLifecycleOwner.current
    val context = LocalContext.current
    var cameraControl: CameraControl? by remember { mutableStateOf(null) }

    AndroidView(factory = { ctx ->
        PreviewView(ctx).apply {
            scaleType = PreviewView.ScaleType.FILL_CENTER
        }
    }, modifier = modifier, update = { previewView ->
        val cameraExecutor = Executors.newSingleThreadExecutor()
        val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
        cameraProviderFuture.addListener({
            val cameraProvider = cameraProviderFuture.get()
            val preview = Preview.Builder().build().also {
                it.setSurfaceProvider(previewView.surfaceProvider)
            }


            // 2. 创建 ImageAnalysis 用例（核心分析逻辑）
            val imageAnalysis = ImageAnalysis.Builder().setImageQueueDepth(1)
                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST) // 仅保留最新帧
                .setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_YUV_420_888) // 输出格式
                .build().apply {
                    setAnalyzer(cameraExecutor, BarcodeAnalyzer(onScan))
                }


            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

            try {
                cameraProvider.unbindAll()
                val camera = cameraProvider.bindToLifecycle(
                    lifecycleOwner, cameraSelector, preview, imageAnalysis
                )
                cameraControl = camera.cameraControl
            } catch (e: Exception) {
                Log.e("QRScanner", "Camera Bind Error", e)
            }
        }, ContextCompat.getMainExecutor(context))
    })
}

图像分析采用

"com.google.mlkit:barcode-scanning"

class BarcodeAnalyzer(private val onScan: (String) -> Unit) : ImageAnalysis.Analyzer {
    val options = BarcodeScannerOptions.Builder()
        .setBarcodeFormats(Barcode.FORMAT_QR_CODE) // 仅扫描标准二维码
        .build()
    private val scanner = BarcodeScanning.getClient()

    @OptIn(ExperimentalGetImage::class)
    override fun analyze(imageProxy: ImageProxy) {
        val mediaImage = imageProxy.image ?: run {
            imageProxy.close()
            return
        }

        if (mediaImage.format != ImageFormat.YUV_420_888) {
            imageProxy.close()
            return
        }

        val image = InputImage.fromMediaImage(mediaImage, imageProxy.imageInfo.rotationDegrees)
        scanner.process(image)
            .addOnSuccessListener { barcodes ->
                barcodes.firstOrNull()?.rawValue?.let { result ->
                    onScan(result)
                }
            }
            .addOnCompleteListener {
                imageProxy.close()
            }
    }
}