安卓扫码功能实现详细步骤

实现安卓扫码功能的步骤如下：

1. 添加依赖库

在项目的build.gradle文件中，添加依赖库：

implementation 'com.google.android.gms:play-services-vision:20.1.2'
implementation 'com.journeyapps:zxing-android-embedded:3.6.0'

2. 在布局文件中添加SurfaceView

在需要扫码的布局文件中添加SurfaceView控件：

<SurfaceView
    android:id="@+id/surfaceView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

3. 创建扫码界面

在Activity中创建扫码界面，实现SurfaceHolder.Callback接口，重写surfaceCreated、surfaceChanged、surfaceDestroyed方法。

public class ScanActivity extends AppCompatActivity implements SurfaceHolder.Callback {
    private static final String TAG = "ScanActivity";
    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;
    private BarcodeDetector barcodeDetector;
    private CameraSource cameraSource;

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

        surfaceView = findViewById(R.id.surfaceView);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);

        barcodeDetector = new BarcodeDetector.Builder(this)
                .setBarcodeFormats(Barcode.QR_CODE)
                .build();

        cameraSource = new CameraSource.Builder(this, barcodeDetector)
                .setAutoFocusEnabled(true)
                .build();
    }

    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        try {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, 1);
            } else {
                cameraSource.start(surfaceHolder);
            }
        } catch (IOException e) {
            Log.e(TAG, e.getMessage());
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
        cameraSource.stop();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        if (requestCode == 1) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                try {
                    cameraSource.start(surfaceHolder);
                } catch (IOException e) {
                    Log.e(TAG, e.getMessage());
                }
            } else {
                Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

4. 解析扫码结果

在扫码界面中，使用BarcodeDetector解析扫码结果。

barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
    @Override
    public void release() {
    }

    @Override
    public void receiveDetections(Detector.Detections<Barcode> detections) {
        final SparseArray<Barcode> barcodes = detections.getDetectedItems();
        if (barcodes.size() > 0) {
            String barcodeValue = barcodes.valueAt(0).displayValue;
            Log.i(TAG, "Barcode value: " + barcodeValue);
        }
    }
});

5. 添加动态权限请求

在AndroidManifest.xml文件中，添加相机权限：

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

在扫码界面的onCreate方法中，请求相机权限：

if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, 1);
} else {
    cameraSource.start(surfaceHolder);
}

6. 运行程序

完成以上步骤后，运行程序即可使用安卓扫码功能。