Android CameraX QR 扫描仪仅在模拟器中工作，不适用于物理设备

Question

我正在为一个学校项目开发一个应用程序，它涉及扫描二维码。我已经使用 Android 模拟器上的 CameraX 库完美地完成了 QR 码扫描，但是当我导出 APK 并将其安装到我的手机 (LG Velvet) 上时，它不会扫描任何代码。相机仍然拉起，我可以看到预览，但它似乎无法识别代码。

这是我的 build.gradle 文件：

plugins {
    id 'com.android.application'
    id 'com.google.gms.google-services'
}

android {
    compileSdk 32

    defaultConfig {
        applicationId "com.example.qrhunter"
        minSdk 24
        targetSdk 32
        versionCode 1
        versionName "1.0"
        multiDexEnabled true;

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        debug {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.4.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.2'
    implementation 'com.google.firebase:firebase-firestore:21.4.0'
    implementation 'com.google.firebase:firebase-auth:20.0.4'
    implementation 'com.google.firebase:firebase-storage:20.0.1'
    implementation "io.grpc:grpc-okhttp:1.32.2"
    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

    //Camera Dependencies
    def camerax_version = "1.1.0-beta01"
    implementation "androidx.camera:camera-camera2:${camerax_version}"
    implementation "androidx.camera:camera-lifecycle:${camerax_version}"
    implementation "androidx.camera:camera-core:${camerax_version}"
    implementation "androidx.camera:camera-view:${camerax_version}"

    //Zebra Crossing Dependencies
    implementation 'com.journeyapps:zxing-android-embedded:4.2.0'
}

这也是我的 AndroidManifest.xml 文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.qrhunter">

    <uses-feature android:name="android.hardware.camera.any" />

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.QRHunter">
        <activity
            android:name=".Login"
            android:exported="false" />
        <activity
            android:name=".Register"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".qrAddObjectPictureActivity"
            android:exported="false" />
        <activity
            android:name=".qrScannedGetInfoActivity"
            android:exported="false" />
        <activity
            android:name=".qrScanCameraActivity"
            android:exported="false" />

        <meta-data
            android:name="preloaded_fonts"
            android:resource="@array/preloaded_fonts" />
    </application>

</manifest>

这是我初始化相机和 QR 分析器的代码

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.Camera;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.Preview;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.camera.view.PreviewView;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.lifecycle.LifecycleOwner;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.util.Size;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.google.common.util.concurrent.ListenableFuture;

import java.util.concurrent.ExecutionException;

/**
 * Activity for running and managing the camera used to scan QR Codes
 * Code for camera usage and qr scanning referenced from: https://learntodroid.com/how-to-create-a-qr-code-scanner-app-in-android/
 */
public class qrScanCameraActivity extends AppCompatActivity {
    private static final int PERMISSION_REQUEST_CAMERA = 0;

    private PreviewView cameraPreviewView;
    private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;

    private Button qrCodeFoundButton;
    private String qrCode;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera);

        cameraPreviewView = findViewById(R.id.cameraPreviewView);
        qrCodeFoundButton = findViewById(R.id.cameraActivity_qrCodeFoundButton);

        qrCodeFoundButton.setVisibility(View.INVISIBLE);
        qrCodeFoundButton.setOnClickListener(new View.OnClickListener() {
            // onClick function for the QR Code Found Button
            @Override
            public void onClick(View view){
                Log.i(qrScanCameraActivity.class.getSimpleName(), "QR Code Found: " + qrCode);
                Intent qrScannedIntent = new Intent(qrScanCameraActivity.this, qrScannedGetInfoActivity.class);
                qrScannedIntent.putExtra("QR_Content", qrCode);
                qrScannedIntent.putExtra("entryFromScanBool", true);
                startActivity(qrScannedIntent);
            }
        });

        cameraProviderFuture = ProcessCameraProvider.getInstance(this);
        requestCamera();
    }

    /**
     * Requests permission to use the camera in the application
     */
    private void requestCamera() {
        if(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED){
            startCamera();
        }else{
            if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)){
                ActivityCompat.requestPermissions(qrScanCameraActivity.this, new String[]{Manifest.permission.CAMERA}, PERMISSION_REQUEST_CAMERA);
            }else{
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, PERMISSION_REQUEST_CAMERA);
            }
        }
    }

    @SuppressLint("MissingSuperCall") //Do not need the super method call unless dealing with fragments
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults){
        if(requestCode == PERMISSION_REQUEST_CAMERA){
            if(grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED){ //if permissions were granted start camera
                startCamera();
            }else{
                Toast.makeText(this, "Camera Permission Denied, please allow camera use in settings", Toast.LENGTH_SHORT).show();
            }
        }
    }

    /**
     * start the camera and bind the preview correctly
     * catch any exceptions
     */
    private void startCamera(){
        cameraProviderFuture.addListener(() -> {
            try{
                ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
                bindCameraPreview(cameraProvider);
            }catch(ExecutionException | InterruptedException e) { //catch any errors when starting the camera
                Toast.makeText(this, "Error starting camera " + e.getMessage(), Toast.LENGTH_SHORT).show();
            }
        }, ContextCompat.getMainExecutor(this));
    }

    /**
     * binds the created camera to the camera preview view in order to allow user to see camera view
     * set the analyzer for the camera to detect QR Codes
     * @param cameraProvider object representing the Camera
     */
    private void bindCameraPreview(@NonNull ProcessCameraProvider cameraProvider){
        cameraPreviewView.setImplementationMode(PreviewView.ImplementationMode.PERFORMANCE);

        Preview preview = new Preview.Builder().build();

        CameraSelector cameraSelector = new CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build();

        preview.setSurfaceProvider(cameraPreviewView.getSurfaceProvider());

        ImageAnalysis imageAnalysis = new ImageAnalysis.Builder().setTargetResolution(new Size(1280,720))
                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST).build();

        imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(this), new QRCodeImageAnalyzer(new QRCodeListener() {
            @Override
            public void qrCodeFound(String _qrCode) {
                qrCode = _qrCode;
                qrCodeFoundButton.setVisibility(View.VISIBLE);
            }

            @Override
            public void qrCodeNotFound() {
                qrCodeFoundButton.setVisibility(View.INVISIBLE);
            }
        }));

        Camera camera = cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, imageAnalysis, preview);
    }

    @Override
    public void onBackPressed() {
        finish();
    }

}

我不确定问题还存在于哪里，因为所有代码都可以完美运行。我的手机在 Android 11、API 30 上运行，我的模拟器也在同一设备上运行（Pixel XL、API 30、Android 11） 对此的任何帮助将不胜感激

编辑：添加分析器代码

/**
 * Class for analyzing frames of camera to check for QR Code, and decode QR Code
 * Code is referenced from: https://learntodroid.com/how-to-create-a-qr-code-scanner-app-in-android/
 */
public class QRCodeImageAnalyzer implements ImageAnalysis.Analyzer {
    private QRCodeListener listener;

    /**
     * Constructor for QRCodeImageAnalyzer
     * @param listener
     */
    public QRCodeImageAnalyzer(QRCodeListener listener){
        this.listener = listener;
    }

    @Override
    public void analyze(@NonNull ImageProxy image){
        if(image.getFormat() == YUV_420_888 || image.getFormat() == YUV_422_888 || image.getFormat() == YUV_444_888){
            ByteBuffer byteBuffer = image.getPlanes()[0].getBuffer();
            byte[] imageData = new byte[byteBuffer.capacity()];
            byteBuffer.get(imageData);

            PlanarYUVLuminanceSource source = new PlanarYUVLuminanceSource(imageData, image.getWidth(), image.getHeight(),
                    0, 0, image.getWidth(), image.getHeight(), false);

            BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(source));

            try{
                Result result = new QRCodeMultiReader().decode(binaryBitmap);
                listener.qrCodeFound(result.getText());
            }catch(FormatException | ChecksumException | NotFoundException e) {
                listener.qrCodeNotFound();
            }
        }
        image.close();
    }
}

Answer 1

您没有提供 QRCodeImageAnalyzer 实现，也许问题就在那里。

以下代码对我有用。注意：我在调用活动而不是扫描仪活动中进行相机权限检查，因此这里缺少它。

public final class ScanQRCodeActivity extends AppCompatActivity {

    public static final String EXTRA_SCANNED_QR_CODE_TEXT = "mypackage.QR_CODE_TEXT";

    private final ExecutorService cameraExecutor = Executors.newSingleThreadExecutor();
    private ProcessCameraProvider cameraProvider;
    private Camera camera;

    private ActivityScanQrCodeBinding binding;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityScanQrCodeBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());
        startCamera();
    }

    @Override
    protected void onDestroy() {
        cameraExecutor.shutdown();
        super.onDestroy();
    }

    private void startCamera() {
        Executor mainExecutor = ContextCompat.getMainExecutor(this);
        ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(this);
        cameraProviderFuture.addListener(() -> onGotCamera(cameraProviderFuture), mainExecutor);
    }

    @MainThread
    private void onGotCamera(@NonNull ListenableFuture<ProcessCameraProvider> cameraProviderFuture) {
        Preview previewUseCase = new Preview.Builder().build();
        previewUseCase.setSurfaceProvider(binding.scanQrCodePreviewView.getSurfaceProvider());

        ImageAnalysis imageAnalysis = new ImageAnalysis.Builder()
                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
                .build();

        BarcodeAnalyzer barcodeAnalyzer = new BarcodeAnalyzer(this::onGotBarcodes);
        imageAnalysis.setAnalyzer(cameraExecutor, barcodeAnalyzer);

        try {
            cameraProvider = cameraProviderFuture.get();
            cameraProvider.unbindAll();
            CameraSelector cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA;
            camera = cameraProvider.bindToLifecycle(this, cameraSelector, previewUseCase, imageAnalysis);
            setupTapToFocus();
        }
        catch (ExecutionException | InterruptedException e) {
            setResultCanceledAndFinish();
        }
    }

    @MainThread
    private void onGotBarcodes(@NonNull List<Barcode> barcodes) {
        cameraProvider.unbindAll();     // we don't want any more barcodes
        String scannedQRCodeText = barcodes.get(0).getDisplayValue();
        setResultOkAndFinish(scannedQRCodeText);
    }

    private void setResultOkAndFinish(@Nullable String scannedQRCodeText) {
        setResult(RESULT_OK, new Intent().putExtra(EXTRA_SCANNED_QR_CODE_TEXT, scannedQRCodeText));
        finish();
    }

    private void setResultCanceledAndFinish() {
        setResult(RESULT_CANCELED);
        finish();
    }

    private void setupTapToFocus() {
        binding.scanQrCodePreviewView.setOnTouchListener(this::onTouch);
    }

    private boolean onTouch(@NonNull View view, @NonNull MotionEvent event) {
        int actionMasked = event.getActionMasked();

        if (actionMasked == MotionEvent.ACTION_UP) {
            view.performClick();
            return false;
        }

        if (actionMasked != MotionEvent.ACTION_DOWN) {
            return false;
        }

        focus(event.getX(), event.getY());
        return true;
    }

    private void focus(float focusPointX, float focusPointY) {
        CameraControl cameraControl = camera.getCameraControl();

        MeteringPointFactory factory = binding.scanQrCodePreviewView.getMeteringPointFactory();
        MeteringPoint point = factory.createPoint(focusPointX, focusPointY);
        FocusMeteringAction action = new FocusMeteringAction.Builder(point, FocusMeteringAction.FLAG_AF)
                .addPoint(point, FocusMeteringAction.FLAG_AE)
                .addPoint(point, FocusMeteringAction.FLAG_AWB)
                .build();

        cameraControl.startFocusAndMetering(action);
    }
}

分析器：

public final class BarcodeAnalyzer implements ImageAnalysis.Analyzer {

    private final BarcodeScanner barcodeScanner = createBarcodeScanner();
    private final BarcodesListener barcodesListener;

    @FunctionalInterface
    public interface BarcodesListener {
        void invoke(List<Barcode> barcodes);
    }

    public BarcodeAnalyzer(BarcodesListener barcodesListener) {
        this.barcodesListener = barcodesListener;
    }

    @ExperimentalGetImage
    @Override
    public void analyze(@NonNull ImageProxy imageProxy) {
        Image image = imageProxy.getImage();
        if (image == null) {
            imageProxy.close();
            return;
        }

        int rotationDegrees = imageProxy.getImageInfo().getRotationDegrees();
        InputImage inputImage = InputImage.fromMediaImage(image, rotationDegrees);
        barcodeScanner.process(inputImage)
                .addOnSuccessListener(this::onGotBarcodes)
                .addOnCompleteListener(task -> imageProxy.close());
    }

    private void onGotBarcodes(List<Barcode> barcodes) {
        if (barcodes != null && !barcodes.isEmpty()) {
            barcodesListener.invoke(barcodes);
        }
    }

    private BarcodeScanner createBarcodeScanner() {
        BarcodeScannerOptions options = new BarcodeScannerOptions.Builder().setBarcodeFormats(Barcode.FORMAT_QR_CODE).build();
        return BarcodeScanning.getClient(options);
    }
}

所需的依赖项（camerax 和 MLKit）：

dependencies {
    // ...
    
    implementation 'androidx.camera:camera-camera2:1.1.0-beta02'
    implementation 'androidx.camera:camera-lifecycle:1.1.0-beta02'
    implementation 'androidx.camera:camera-view:1.1.0-beta02'
    implementation 'com.google.mlkit:barcode-scanning:17.0.2'