android 识别图片上的二维码

 

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;
	}
}

 

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();
                }