Question

我需要实施条形码扫描应用。具体的特点是我需要片段的预览显示，适合半个屏幕（或说250 dp）。因此，我使用this库及其ScannerFragment类来实现相机预览和条形码扫描。问题是在纵向（我只需要此模式，而不是横向）模式相机预览被拉伸，扫描仪无法识别其中的条形码。它的横向模式工作正常。

我的布局文件：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    android:orientation="horizontal">

    <FrameLayout

        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="top">

        <fragment android:name="ua.xajker.inventarization.BarcodeScanActivity.ScannerFragment"
            android:id="@+id/headlines_fragment"
            android:layout_weight="1"
            android:layout_width="fill_parent"
            android:layout_height="250dp"/>

    </FrameLayout>

</LinearLayout>

My Fragment课程：

public class ScannerFragment extends Fragment implements ZXingScannerView.ResultHandler {
    private ZXingScannerView mScannerView;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mScannerView = new ZXingScannerView(getActivity());
        return mScannerView;
    }


    @Override
    public void onResume() {
        super.onResume();
        mScannerView.setResultHandler(this);

        mScannerView.startCamera();
        mScannerView.setAutoFocus(false);
    }


    @Override
    public void handleResult(Result rawResult) {
        Toast.makeText(getActivity(), "Contents = " + rawResult.getText() +
                ", Format = " + rawResult.getBarcodeFormat().toString(), Toast.LENGTH_SHORT).show();
        mScannerView.startCamera();
    }


    @Override
    public void onPause() {
        super.onPause();
        mScannerView.stopCamera();
    }
}

我发现我们可以替换lib的ZXingScannerView.java类，我们可以用Camera对象操作，也许它会有所帮助吗？

public class ZXingScannerView extends BarcodeScannerView {

    public interface ResultHandler {
        public void handleResult(Result rawResult);
    }


    private MultiFormatReader mMultiFormatReader;
    public static final List<BarcodeFormat> ALL_FORMATS = new ArrayList<BarcodeFormat>();
    private List<BarcodeFormat> mFormats;
    private ResultHandler mResultHandler;


    static {
        ALL_FORMATS.add(BarcodeFormat.UPC_A);
        ALL_FORMATS.add(BarcodeFormat.UPC_E);
        ALL_FORMATS.add(BarcodeFormat.EAN_13);
        ALL_FORMATS.add(BarcodeFormat.EAN_8);
        ALL_FORMATS.add(BarcodeFormat.RSS_14);
        ALL_FORMATS.add(BarcodeFormat.CODE_39);
        ALL_FORMATS.add(BarcodeFormat.CODE_93);
        ALL_FORMATS.add(BarcodeFormat.CODE_128);
        ALL_FORMATS.add(BarcodeFormat.ITF);
        ALL_FORMATS.add(BarcodeFormat.CODABAR);
        ALL_FORMATS.add(BarcodeFormat.QR_CODE);
        ALL_FORMATS.add(BarcodeFormat.DATA_MATRIX);
        ALL_FORMATS.add(BarcodeFormat.PDF_417);
    }


    public ZXingScannerView(Context context) {
        super(context);
        initMultiFormatReader();
    }


    public ZXingScannerView(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
        initMultiFormatReader();
    }


    public void setFormats(List<BarcodeFormat> formats) {
        mFormats = formats;
        initMultiFormatReader();
    }


    public void setResultHandler(ResultHandler resultHandler) {
        mResultHandler = resultHandler;
    }


    public Collection<BarcodeFormat> getFormats() {
        if(mFormats == null) {
            return ALL_FORMATS;
        }
        return mFormats;
    }


    private void initMultiFormatReader() {
        Map<DecodeHintType,Object> hints = new EnumMap<DecodeHintType,Object>(DecodeHintType.class);
        hints.put(DecodeHintType.POSSIBLE_FORMATS, getFormats());
        mMultiFormatReader = new MultiFormatReader();
        mMultiFormatReader.setHints(hints);
    }


    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        Camera.Parameters parameters = camera.getParameters();
        Camera.Size size = parameters.getPreviewSize();

        int width = size.width;
        int height = size.height;

        if(DisplayUtils.getScreenOrientation(getContext()) == Configuration.ORIENTATION_PORTRAIT) {
            byte[] rotatedData = new byte[data.length];
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++)
                    rotatedData[x * height + height - y - 1] = data[x + y * width];
            }
            int tmp = width;
            width = height;
            height = tmp;
            data = rotatedData;
        }


        Result rawResult = null;
        PlanarYUVLuminanceSource source = buildLuminanceSource(data, width, height);


        if(source != null) {
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
            try {
                rawResult = mMultiFormatReader.decodeWithState(bitmap);
            } catch (ReaderException re) {
                // continue
            } catch (NullPointerException npe) {
                // This is terrible
            } catch (ArrayIndexOutOfBoundsException aoe) {


            } finally {
                mMultiFormatReader.reset();
            }
        }


        if (rawResult != null) {
            stopCamera();
            if(mResultHandler != null) {
                mResultHandler.handleResult(rawResult);
            }
        } else {
            camera.setOneShotPreviewCallback(this);
        }
    }


    public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
        Rect rect = getFramingRectInPreview(width, height);
        if (rect == null) {
            return null;
        }
        // Go ahead and assume it's YUV rather than die.
        PlanarYUVLuminanceSource source = null;


        try {
            source = new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                    rect.width(), rect.height(), false);
        } catch(Exception e) {
        }


        return source;
    }
}

发布照片我没有声誉，因此您可以看到 here 的截图。

非常感谢任何建议。

设置android相机预览适合屏幕的一半

0 个答案: