Question

我有一个github项目使用Zxing Library扫描QR码，但不知怎的，我也无法获得扫描图像和QR码。这是我的代码。在gradle我使用：

Gradle Compile Statment

的build.gradle

    compile 'me.dm7.barcodescanner:core:1.9'
    compile 'com.google.zxing:core:3.2.1'

您可以在下面看到我的活动和xml代码。

ScanQR_Code_Activity.java

package com.rishi.myaadhaar.activities;

import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.ViewGroup;
import android.widget.Toast;

import com.google.zxing.Result;
import com.myadhaar.R;

import java.util.ArrayList;

public class ScanQR_Code_Activity extends AppCompatActivity implements ZXingScannerView.ResultHandler {

    private static final String FLASH_STATE = "FLASH_STATE";

    // UI Elements
    private static final String AUTO_FOCUS_STATE = "AUTO_FOCUS_STATE";
    private static final String SELECTED_FORMATS = "SELECTED_FORMATS";
    private static final String CAMERA_ID = "CAMERA_ID";
    String uid, name, gender, yearOfBirth, careOf, villageTehsil, postOffice, house, street, loc, district, state, postCode, lm;
    ViewGroup contentFrame;
    private ZXingScannerView mScannerView;
    private boolean mFlash;
    private boolean mAutoFocus;
    private ArrayList<Integer> mSelectedIndices;
    private int mCameraId = -1;

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

        if (savedInstanceState != null) {
            mFlash = savedInstanceState.getBoolean(FLASH_STATE, false);
            mAutoFocus = savedInstanceState.getBoolean(AUTO_FOCUS_STATE, true);
            mSelectedIndices = savedInstanceState.getIntegerArrayList(SELECTED_FORMATS);
            mCameraId = savedInstanceState.getInt(CAMERA_ID, -1);
        } else {
            mFlash = false;
            mAutoFocus = true;
            mSelectedIndices = null;
            mCameraId = -1;
        }

        contentFrame = (ViewGroup) findViewById(R.id.content_frame);
        mScannerView = new ZXingScannerView(this);
        contentFrame.addView(mScannerView);
    }

    @Override
    public void onResume() {
        super.onResume();
        mScannerView.setResultHandler(this);
        mScannerView.startCamera();
        mScannerView.setFlash(mFlash);
        mScannerView.setAutoFocus(mAutoFocus);
    }

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

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

        if (rawResult != null && !rawResult.getText().toString().isEmpty()) {
            //processScannedData(rawResult.getText());
        } else {
            Toast toast = Toast.makeText(getApplicationContext(), "Scan Cancelled", Toast.LENGTH_SHORT);
            toast.show();
        }

        // Note:
        // * Wait 2 seconds to resume the preview.
        // * On older devices continuously stopping and resuming camera preview can result in freezing the app.
        // * I don't know why this is the case but I don't have the time to figure out.
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScannerView.resumeCameraPreview(ScanQR_Code_Activity.this);
            }
        }, 2000);
    }
}

activity_scan_qr_code.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_scan_qr_code"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.rishi.myaadhaar.activities.ScanQR_Code_Activity">


    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />



</RelativeLayout>

扩展课程

public class ZXingScannerView extends BarcodeScannerView {
    private static final String TAG = "ZXingScannerView";

    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) {
        if(mResultHandler == null) {
            return;
        }

        try {
            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();
                }
            }

            final Result finalRawResult = rawResult;

            if (finalRawResult != null) {
                Handler handler = new Handler(Looper.getMainLooper());
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        // Stopping the preview can take a little long.
                        // So we want to set result handler to null to discard subsequent calls to
                        // onPreviewFrame.
                        ResultHandler tmpResultHandler = mResultHandler;
                        mResultHandler = null;

                        stopCameraPreview();
                        if (tmpResultHandler != null) {
                            tmpResultHandler.handleResult(finalRawResult);
                        }
                    }
                });
            } else {
                camera.setOneShotPreviewCallback(this);
            }
        } catch(RuntimeException e) {
            // TODO: Terrible hack. It is possible that this method is invoked after camera is released.
            Log.e(TAG, e.toString(), e);
        }
    }

    public void resumeCameraPreview(ResultHandler resultHandler) {
        mResultHandler = resultHandler;
        super.resumeCameraPreview();
    }

    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;
    }
}

Answer 1

ZXing不会将其退还给您。我建议在扫描时从取景器中抓取框架。它不会是确切的图像，但是将在触发扫描的帧之前或之后是一帧。

Answer 2

像这样从handleResult（）方法调用generateQRCode（）方法

@Override
public void handleResult(Result rawResult) {
    generateQRCode(rawResult.getResultMetadata().toString());
}

public void generateQRCode(String data){
    com.google.zxing.Writer wr = new MultiFormatWriter();
    try {
        int width = 350;
        int height = 350;
        BitMatrix bm = wr.encode(data, BarcodeFormat.QR_CODE, width, height);
        mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

        for (int i = 0; i < width; i++) {
            for (int j = 0; j < height; j++) {

                mBitmap.setPixel(i, j, bm.get(i, j) ? Color.BLACK : Color.WHITE);
            }
        }
    } catch (WriterException e) {
        e.printStackTrace();
    }
    if (mBitmap != null) {
        img.setImageBitmap(mBitmap);
    }
}

如何使用Zxing Library获取扫描图片和QR码

2 个答案: