1.在你的build.gradle文件中添加Mobile Vision库的依赖：

dependencies {implementation 'com.google.android.gms:play-services-vision:20.1.0'
}

2.创建一个新的Activity来处理扫描过程。

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.appcompat.app.AppCompatActivity;
import com.google.android.gms.vision.barcode.BarcodeReader;
import com.google.android.gms.vision.CameraSource;
import com.google.android.gms.vision.barcode.Barcode;
import android.util.SparseArray;
import com.google.android.gms.vision.Detector;
import android.view.SurfaceHolder;
import android.view.SurfaceView;public class QRCodeScannerActivity extends AppCompatActivity {private SurfaceView cameraPreview;private CameraSource cameraSource;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_qrcode_scanner);cameraPreview = findViewById(R.id.camera_preview);BarcodeReader barcodeReader = new BarcodeReader.Builder(this).build();cameraSource = new CameraSource.Builder(this, barcodeReader).setFacing(CameraSource.CAMERA_FACING_BACK).setRequestedPreviewSize(1600, 1024).setAutoFocusEnabled(true).build();cameraPreview.getHolder().addCallback(new SurfaceHolder.Callback() {@Overridepublic void surfaceCreated(SurfaceHolder holder) {if (ContextCompat.checkSelfPermission(QRCodeScannerActivity.this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {try {cameraSource.start(cameraPreview.getHolder());} catch (IOException e) {e.printStackTrace();}}}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {cameraSource.stop();}});barcodeReader.setProcessor(new Detector.Processor<Barcode>() {@Overridepublic void release() {}@Overridepublic void receiveDetections(Detector.Detections<Barcode> detections) {final SparseArray<Barcode> qrCodes = detections.getDetectedItems();if (qrCodes.size() != 0) {Barcode barcode = qrCodes.valueAt(0);String scannedQRCode = barcode.displayValue;// Handle the scanned code as needed}}});}@Overrideprotected void onDestroy() {super.onDestroy();cameraSource.release();}
}

3.确保你的AndroidManifest.xml文件中添加了相应的权限

<uses-permission android:name="android.permission.CAMERA" />