android 分辨图片上的二维码

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Android 使用ZXing库识别图片上的二维码：

1.? EncodingHandler.java 文件：

public final class EncodingHandler {	private static final int BLACK = 0xff000000;		public static Bitmap createQRCode(String str,int widthAndHeight) throws WriterException {		Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();          hints.put(EncodeHintType.CHARACTER_SET, "utf-8"); 		BitMatrix matrix = new MultiFormatWriter().encode(str,				BarcodeFormat.QR_CODE, widthAndHeight, widthAndHeight);		int width = matrix.getWidth();		int height = matrix.getHeight();		int[] pixels = new int[width * height];				for (int y = 0; y < height; y++) {			for (int x = 0; x < width; x++) {				if (matrix.get(x, y)) {					pixels[y * width + x] = BLACK;				}			}		}		Bitmap bitmap = Bitmap.createBitmap(width, height,				Bitmap.Config.ARGB_8888);		bitmap.setPixels(pixels, 0, width, 0, 0, width, height);		return bitmap;	}}

?2. RGBLuminanceSource 类继承ZXing库中的LuminanceSource类：

public class RGBLuminanceSource extends LuminanceSource {	private final byte[] luminances;	private final int dataWidth;	private final int dataHeight;	private final int left;	private final int top;	public RGBLuminanceSource(Bitmap bitmap) {		super(bitmap.getWidth(), bitmap.getHeight());		// TODO Auto-generated constructor stub		int width = bitmap.getWidth();		int height = bitmap.getHeight();		int[] pixels = new int[width * height];		bitmap.getPixels(pixels, 0, bitmap.getWidth(), 0, 0, bitmap.getWidth(), bitmap.getHeight());		dataWidth = width;		dataHeight = height;		left = 0;		top = 0;		// In order to measure pure decoding speed, we convert the entire image to a greyscale array		// up front, which is the same as the Y channel of the YUVLuminanceSource in the real app.		luminances = new byte[width * height];		for (int y = 0; y < height; y++) {			int offset = y * width;			for (int x = 0; x < width; x++) {				int pixel = pixels[offset + x];				int r = (pixel >> 16) & 0xff;				int g = (pixel >> 8) & 0xff;				int b = pixel & 0xff;				if (r == g && g == b) {					// Image is already greyscale, so pick any channel.					luminances[offset + x] = (byte) r;				} else {					// Calculate luminance cheaply, favoring green.					luminances[offset + x] = (byte) ((r + g + g + b) >> 2);				}			}		}	}	@Override	public byte[] getMatrix() {		// TODO Auto-generated method stub		int width = getWidth();		int height = getHeight();		// If the caller asks for the entire underlying image, save the copy and give them the		// original data. The docs specifically warn that result.length must be ignored.		if (width == dataWidth && height == dataHeight) {			return luminances;		}		int area = width * height;		byte[] matrix = new byte[area];		int inputOffset = top * dataWidth + left;		// If the width matches the full width of the underlying data, perform a single copy.		if (width == dataWidth) {			System.arraycopy(luminances, inputOffset, matrix, 0, area);			return matrix;		}		// Otherwise copy one cropped row at a time.		byte[] rgb = luminances;		for (int y = 0; y < height; y++) {			int outputOffset = y * width;			System.arraycopy(rgb, inputOffset, matrix, outputOffset, width);			inputOffset += dataWidth;		}		return matrix;	}	@Override	public byte[] getRow(int y, byte[] row) {		// TODO Auto-generated method stub		if (y < 0 || y >= getHeight()) {			throw new IllegalArgumentException("Requested row is outside the image: " + y);		}		int width = getWidth();		if (row == null || row.length < width) {			row = new byte[width];		}		int offset = (y + top) * dataWidth + left;		System.arraycopy(luminances, offset, row, 0, width);		return row;	}}

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2，识别图片二维码的代码：

 Hashtable<DecodeHintType, String> hints = new Hashtable<DecodeHintType, String>();                hints.put(DecodeHintType.CHARACTER_SET, "utf-8"); // 设置二维码内容的编码                BitmapFactory.Options options = new BitmapFactory.Options();                options.inJustDecodeBounds = true; // 先获取原大小                Bitmap scanBitmap = BitmapFactory.decodeFile("/mnt/sdcard/temp_QRCode.png", options);                options.inJustDecodeBounds = false; // 获取新的大小                int sampleSize = (int) (options.outHeight / (float) 200);                if (sampleSize <= 0)                    sampleSize = 1;                options.inSampleSize = sampleSize;                scanBitmap = BitmapFactory.decodeFile("/mnt/sdcard/temp_QRCode.png", options);                RGBLuminanceSource source = new RGBLuminanceSource(scanBitmap);                BinaryBitmap bitmap1 = new BinaryBitmap(new HybridBinarizer(source));                QRCodeReader reader = new QRCodeReader();                try {                    Result result = reader.decode(bitmap1, hints);                    if (result != null) {                        String data = result.toString();                        Toast.makeText(MainActivity.this, "Data= " + data, Toast.LENGTH_LONG).show();                    }                } catch (NotFoundException e) {                    e.printStackTrace();                } catch (ChecksumException e) {                    e.printStackTrace();                } catch (FormatException e) {                    e.printStackTrace();                }

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