这个是一个工具类，把所有支持的几个write写在里面了。
public BitMatrix encode(String contents,
BarcodeFormat format,
int width, int height,
Map<EncodeHintType,?> hints) throws WriterException {
Writer writer;
switch (format) {
case EAN_8:
writer = new EAN8Writer();
break;
case UPC_E:
writer = new UPCEWriter();
break;
case EAN_13:
writer = new EAN13Writer();
break;
case UPC_A:
writer = new UPCAWriter();
break;
case QR_CODE:
writer = new QRCodeWriter();
break;
case CODE_39:
writer = new Code39Writer();
break;
case CODE_93:
writer = new Code93Writer();
break;
case CODE_128:
writer = new Code128Writer();
break;
case ITF:
writer = new ITFWriter();
break;
case PDF_417:
writer = new PDF417Writer();
break;
case CODABAR:
writer = new CodaBarWriter();
break;
case DATA_MATRIX:
writer = new DataMatrixWriter();
break;
case AZTEC:
writer = new AztecWriter();
break;
default:
throw new IllegalArgumentException("No encoder available for format " + format);
}
return writer.encode(contents, format, width, height, hints);
}
这是官方最新支持的格式，具体看引入的jar里面支持的格式。
对与bitmatrix的结果，通过摸个算法，设置每个点白色，或者黑色。
最后创建一张二维码的图片。
4.识别二维码
如何从一张图片上面，识别二维码呢：
public class ReDecodeThread {
public static void encode(final Bitmap bitmap, final ReDecodeThreadResult listener) {
if (listener == null) {
return;
}
if (bitmap == null) {
listener.onReDecodeResult(null);
return;
}
new Thread() {
@Override
public void run() {
try {
MultiFormatReader multiFormatReader = new MultiFormatReader();
BitmapLuminanceSource source = new BitmapLuminanceSource(bitmap);
BinaryBitmap bitmap1 = new BinaryBitmap(new HybridBinarizer(source));
Result result1 = multiFormatReader.decode(bitmap1);
listener.onReDecodeResult(result1.getText());
return;
} catch (NotFoundException e) {
e.printStackTrace();
}
listener.onReDecodeResult(null);
}
}.start();
}
public interface ReDecodeThreadResult {
void onReDecodeResult(String url);
}
}
过程也是很简单，使用MultiFormatReader来分析图片，这里不需要缺人图片的条码格式。
如果分析下源码，就是依次使用每种格式的reader来分析，直到找到合适的为止。
当然回了能够把Bitmap转化成Bitmatrix，然后在分析。
public final class BitmapLuminanceSource extends LuminanceSource{
private final byte[] luminances;
public BitmapLuminanceSource(String path) throws FileNotFoundException {
this(loadBitmap(path));
}
public BitmapLuminanceSource(Bitmap bitmap) {
super(bitmap.getWidth(), bitmap.getHeight());
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int[] pixels = new int[width * height];
bitmap.getPixels(pixels, 0, width, 0, 0, width, height);
// 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[] getRow(int y, byte[] row) {
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];
}
System.arraycopy(luminances, y * width, row, 0, width);
return row;
}
// Since this class does not support cropping, the underlying byte array
// already contains
// exactly what the caller is asking for, so give it to them without a copy.
@Override
public byte[] getMatrix() {
return luminances;
}
private static Bitmap loadBitmap(String path) throws FileNotFoundException {
Bitmap bitmap = BitmapFactory.decodeFile(path);
if (bitmap == null) {
throw new FileNotFoundException("Couldn't open " + path);
}
return bitmap;
}
}
