android - 如何使用camera2检测条码

Question

相机现在已弃用，建议使用 camera2，有人可以指导我了解如何使用 camera2 和检测条形码

Answer 1

这里有2种可能

1. 从头开始创建条形码扫描仪（这很复杂）
2. 使用现有的库（这个答案涵盖）

有一些完善的库可供您使用

• ZXing跨平台库，用 C++ 编写
• ZXing Embedded是一个 Android 端口
• 更易于使用的Google Mobile Vision API

此外，您可以参考此问题以更深入地了解如何将 Camera2 与 Mobile Vision 结合使用。

Answer 2

是的，当然！你必须使用BarcodeDetector. 像这样的东西：

open class BarcodeFragmentInternal : Fragment(), ActivityCompat.OnRequestPermissionsResultCallback {

    protected var mSurfaceView: SurfaceView? = null

    protected var mScanListener: Listener? = null

    private var mCameraSource: CameraSource? = null

    override fun onStart() {
        super.onStart()

        // Initialize Barcode Detector
        // Used to recognize barcodes like {@link Barcode.DATA_MATRIX} and {@link Barcode.QR_CODE}
        val mBarcodeDetector = BarcodeDetector.Builder(activity)
                .setBarcodeFormats(Barcode.DATA_MATRIX or Barcode.QR_CODE)
                .build()
        if (!mBarcodeDetector.isOperational) {
            sendError("NO_BARCODE_DETECTOR")
        }

        mBarcodeDetector.setProcessor(object : Detector.Processor<Barcode> {
            override fun release() {

            }

            override fun receiveDetections(detections: Detector.Detections<Barcode>?) {
                if (detections != null && mScanListener != null) {
                    val detectedItems = detections.detectedItems
                    if (detectedItems != null) {
                        var i = 0
                        val size = detectedItems.size()
                        while (i < size) {
                            val barcode = detectedItems.valueAt(i)
                            mScanListener!!.onQRCodeAvailable(barcode.rawValue)
                            i++
                        }
                    }
                }
            }
        })

        mCameraSource = CameraSource.Builder(context!!, mBarcodeDetector).build()

        mSurfaceView!!.holder.addCallback(object : SurfaceHolder.Callback {
            override fun surfaceCreated(surfaceHolder: SurfaceHolder) {
                try {
                    if (ContextCompat.checkSelfPermission(activity!!, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                        requestCameraPermission()
                        return
                    }
                    mCameraSource!!.start(mSurfaceView!!.holder)
                } catch (e: Exception) {
                    sendError("NO_CAMERA_ACCESS")
                }

            }

            override fun surfaceChanged(surfaceHolder: SurfaceHolder, format: Int, width: Int, height: Int) {

            }

            override fun surfaceDestroyed(surfaceHolder: SurfaceHolder) {
                mCameraSource!!.stop()
            }
        })
    }


    private fun requestCameraPermission() {
        if (shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)) {
            ConfirmationDialog().show(childFragmentManager, FRAGMENT_DIALOG)
        } else {
            requestPermissions(arrayOf(Manifest.permission.CAMERA), REQUEST_CAMERA_PERMISSION)
        }
    }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>,
                                            grantResults: IntArray) {
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults.size != 1 || grantResults[0] != PackageManager.PERMISSION_GRANTED) {

                sendError("NOT_AUTHORIZED")

                view!!.post {
                    ErrorDialog.newInstance(getString(R.string.request_permission))
                            .show(childFragmentManager, FRAGMENT_DIALOG)
                }
            }
        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        }
    }
}