Android 二维码相关(三)

本篇文章主要讲下二维码扫描相关.

1: 权限相关

由于文中需要使用Camera以及surfaceview,所以我们需要提前申请相机权限:

java 复制代码

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

2: 添加SurfaceView预览

xml 复制代码

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ScanActivity">
    <SurfaceView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:id="@+id/surface"
        />
</androidx.constraintlayout.widget.ConstraintLayout>

3: 初始化相机

通过SurfaceView我们获取SurfaceHolder:

java 复制代码

surfaceView = findViewById(R.id.surface);
SurfaceHolder holder = surfaceView.getHolder();
holder.addCallback(new SurfaceHolder.Callback() {
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }
});

surfaceCreated中我们初始化相机配置
surfaceDestroyed 中我们重置参数

3.1 startCamera()

java 复制代码

private void startCamera() {
    Camera open = Camera.open();
    Camera.Parameters parameters = open.getParameters();
    parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
    open.setParameters(parameters);
    open.setDisplayOrientation(90);
    open.setPreviewCallback(new Camera.PreviewCallback() {
            @Override
            public void onPreviewFrame(byte[] data, Camera camera) {
                
            }
    });
    try {
        open.setPreviewDisplay(surfaceView.getHolder());
        open.startPreview();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

3.2 stopCamera()

java 复制代码

private void stopCamera() {
    if (open != null) {
        open.stopPreview();
        open.setPreviewCallback(null);
        open.release();
        open = null;
    }
}

3.3 Camera.PreviewCallback

具体的解析方法,以及数据来源根据Camera.PreviewCallback 的回调来实现:

获取数据的宽高

java 复制代码

Camera.Size previewSize = camera.getParameters().getPreviewSize();
int width = previewSize.width;
int height = previewSize.height;

将预览数据转换为二进制位图

java 复制代码

 PlanarYUVLuminanceSource planarYUVLuminanceSource = new PlanarYUVLuminanceSource(data, width, height, 0, 0, width, height, false);
 BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(planarYUVLuminanceSource));

设置解码参数

java 复制代码

EnumMap<DecodeHintType, Object> decodeHintTypeObjectEnumMap = new EnumMap<>(DecodeHintType.class);
Collection<BarcodeFormat> list = new ArrayList<>();
list.addAll(EnumSet.of(BarcodeFormat.QR_CODE));
decodeHintTypeObjectEnumMap.put(DecodeHintType.POSSIBLE_FORMATS, list);

解码

创建MultiFormatReader对象,用于解码.并通过setHints方法设置解码格式

java 复制代码

MultiFormatReader multiFormatReader = new MultiFormatReader();
multiFormatReader.setHints(decodeHintTypeObjectEnumMap);
try {
    Result decode = multiFormatReader.decode(binaryBitmap);
    String text = decode.getText();
    Log.i("xxxxx", "onPreviewFrame: " + text);
} catch (Throwable e) {
    Log.e("xxxxx", "onPreviewFrame: ", e);
}

注: onPreviewFrame是Android相机预览帧回调函数，它会在每一帧预览数据可用时被调用.

完整的代码如下:

java 复制代码

public class ScanActivity extends AppCompatActivity implements SurfaceHolder.Callback, Camera.PreviewCallback {
    private SurfaceView surfaceView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan);
        surfaceView = findViewById(R.id.surface);
        SurfaceHolder holder = surfaceView.getHolder();
        holder.addCallback(this);
    }

    Camera open;

    private void startCamera() {
        Camera open = Camera.open();
        Camera.Parameters parameters = open.getParameters();
        parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
        open.setParameters(parameters);
        open.setDisplayOrientation(90);
        open.setPreviewCallback(this);
        try {
            open.setPreviewDisplay(surfaceView.getHolder());
            open.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    private void stopCamera() {
        if (open != null) {
            open.stopPreview();
            open.setPreviewCallback(null);
            open.release();
            open = null;
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        startCamera();
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        stopCamera();
    }

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        if (camera == null || camera.getParameters() == null) return;
        Camera.Size previewSize = camera.getParameters().getPreviewSize();
        int width = previewSize.width;
        int height = previewSize.height;
        //预览数据转二进制位图
        PlanarYUVLuminanceSource planarYUVLuminanceSource = new PlanarYUVLuminanceSource(data, width, height, 0, 0, width, height, false);
        BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(planarYUVLuminanceSource));
        // 设置解码参数
        EnumMap<DecodeHintType, Object> decodeHintTypeObjectEnumMap = new EnumMap<>(DecodeHintType.class);
        Collection<BarcodeFormat> list = new ArrayList<>();
        list.addAll(EnumSet.of(BarcodeFormat.QR_CODE));
        decodeHintTypeObjectEnumMap.put(DecodeHintType.POSSIBLE_FORMATS, list);

        MultiFormatReader multiFormatReader = new MultiFormatReader();
        multiFormatReader.setHints(decodeHintTypeObjectEnumMap);
        try {
            Result decode = multiFormatReader.decode(binaryBitmap);
            String text = decode.getText();
            Log.i("xxxxx", "onPreviewFrame: " + text);
        } catch (Throwable e) {
            Log.e("xxxxx", "onPreviewFrame: ", e);
        }
    }
}