二维码的生成与解析

本示例演示使用文本生成对应的二维码图片，和解析二维码图片的内容。代码如下：

MainActivity：

package com.home.testqrcode;

import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.client.androidtest.RGBLuminanceSource;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.google.zxing.qrcode.QRCodeWriter;

public class MainActivity extends Activity implements OnClickListener {
	private Button generateBtn;
	private Button decodeQRCodeBtn;
	private ImageView imageView;
	private TextView textView;
	private EditText contentText;
	private static int QR_WIDTH = 400;
	private static int QR_HEIGHT = 400;

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

	private void initWidget() {
		generateBtn = (Button) findViewById(R.id.main_btn_generateQRCode);
		generateBtn.setOnClickListener(this);
		decodeQRCodeBtn = (Button) findViewById(R.id.main_btn_decodeQRCode);
		decodeQRCodeBtn.setOnClickListener(this);
		imageView = (ImageView) findViewById(R.id.main_iv);
		textView = (TextView) findViewById(R.id.main_tv);
		contentText = (EditText) findViewById(R.id.main_et);
	}

	@Override
	public void onClick(View v) {
		if (v == generateBtn) {
			String text = contentText.getText().toString();
			if ("".equals(text) || null == text) {
				Toast.makeText(this, "请输入内容", Toast.LENGTH_SHORT).show();
				return;
			}
			Bitmap bitmap = createBitmap(text);
			if (bitmap != null) {
				imageView.setImageBitmap(bitmap);
			}
		} else if (v == decodeQRCodeBtn) {
			String content = readImage(imageView);
			textView.setText(content);
		}
	}

	/**
	 * 生成二维码图片
	 * 
	 * @return
	 */
	private Bitmap createBitmap(String text) {
		Bitmap bitmap = null;
		try {
			Hashtable hints = new Hashtable();
			hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
			BitMatrix bitMatrix = new QRCodeWriter().encode(text,
					BarcodeFormat.QR_CODE, QR_WIDTH, QR_HEIGHT, hints);

			// QRCodeWriter writer = new QRCodeWriter();
			// // 把输入的文本转为二维码
			// BitMatrix bitMatrix = writer.encode(text, BarcodeFormat.QR_CODE,
			// QR_WIDTH, QR_HEIGHT);

			int[] pixels = new int[QR_WIDTH * QR_HEIGHT];
			for (int y = 0; y < QR_HEIGHT; y++) {
				for (int x = 0; x < QR_WIDTH; x++) {
					if (bitMatrix.get(x, y)) {
						pixels[y * QR_WIDTH + x] = 0xff000000;
					} else {
						pixels[y * QR_WIDTH + x] = 0xffffffff;
					}

				}
			}
			bitmap = Bitmap.createBitmap(QR_WIDTH, QR_HEIGHT,
					Bitmap.Config.ARGB_8888);
			bitmap.setPixels(pixels, 0, QR_WIDTH, 0, 0, QR_WIDTH, QR_HEIGHT);

		} catch (WriterException e) {
			e.printStackTrace();
		}
		return bitmap;
	}

	/**
	 * 解析QR图内容
	 * 
	 * @param imageView
	 * @return
	 */
	private String readImage(ImageView imageView) {
		String content = null;
		Map hints = new HashMap();
		hints.put(DecodeHintType.CHARACTER_SET, "utf-8");

		// 获得待解析的图片
		Bitmap bitmap = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
		RGBLuminanceSource source = new RGBLuminanceSource(bitmap);
		BinaryBitmap bitmap1 = new BinaryBitmap(new HybridBinarizer(source));
		QRCodeReader reader = new QRCodeReader();
		try {
			Result result = reader.decode(bitmap1, hints);
			// 得到解析后的文字
			content = result.getText();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return content;
	}

}

RGBLuminanceSource：

package com.google.zxing.client.androidtest;

import com.google.zxing.LuminanceSource;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import java.io.FileNotFoundException;

/**
 * This class is used to help decode images from files which arrive as RGB data
 * from Android bitmaps. It does not support cropping or rotation.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class RGBLuminanceSource extends LuminanceSource {

	private final byte[] luminances;

	public RGBLuminanceSource(String path) throws FileNotFoundException {
		this(loadBitmap(path));
	}

	public RGBLuminanceSource(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;
	}

}

main.xml：

另外需要在网上下载个二维码的jar：core.jar