使用zxing实现生成二维码

github：
https://github.com/billcarbit/QRCodeDemo

package qrcode.com.qrcodedemo;

/**
 * Created by Administrator on 2016-11-27.
 */

import android.graphics.Bitmap;
import android.graphics.Canvas;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * 二维码生成工具类
 */
public class QRCodeUtils {
    /**
     * 生成二维码Bitmap
     *
     * @param content   内容
     * @param widthPix  图片宽度
     * @param heightPix 图片高度
     * @param logoBm    二维码中心的Logo图标（可以为null）
     * @param filePath  用于存储二维码图片的文件路径
     * @return 生成二维码及保存文件是否成功
     */
    public static boolean createQRImage(String content, int widthPix, int heightPix, Bitmap logoBm, String filePath) {
        try {
            if (content == null || "".equals(content)) {
                return false;
            }

            //配置参数
            Map<EncodeHintType, Object> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            //容错级别
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            //设置空白边距的宽度
            //            hints.put(EncodeHintType.MARGIN, 2); //default is 4

            // 图像数据转换，使用了矩阵转换
            BitMatrix bitMatrix = null;
            bitMatrix = new QRCodeWriter().encode(content, BarcodeFormat.QR_CODE, widthPix, heightPix, hints);
            int[] pixels = new int[widthPix * heightPix];
            // 下面这里按照二维码的算法，逐个生成二维码的图片，
            // 两个for循环是图片横列扫描的结果
            for (int y = 0; y < heightPix; y++) {
                for (int x = 0; x < widthPix; x++) {
                    if (bitMatrix.get(x, y)) {
                        pixels[y * widthPix + x] = 0xff000000;
                    } else {
                        pixels[y * widthPix + x] = 0xffffffff;
                    }
                }
            }

            // 生成二维码图片的格式，使用ARGB_8888
            Bitmap bitmap = Bitmap.createBitmap(widthPix, heightPix, Bitmap.Config.ARGB_8888);
            bitmap.setPixels(pixels, 0, widthPix, 0, 0, widthPix, heightPix);

            if (logoBm != null) {
                bitmap = addLogo(bitmap, logoBm);
            }

            //必须使用compress方法将bitmap保存到文件中再进行读取。直接返回的bitmap是没有任何压缩的，内存消耗巨大！
            return bitmap != null && bitmap.compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(filePath));
        } catch (WriterException | IOException e) {
            e.printStackTrace();
        }

        return false;
    }

    /**
     * 在二维码中间添加Logo图案
     */
    private static Bitmap addLogo(Bitmap src, Bitmap logo) {
        if (src == null) {
            return null;
        }

        if (logo == null) {
            return src;
        }

        //获取图片的宽高
        int srcWidth = src.getWidth();
        int srcHeight = src.getHeight();
        int logoWidth = logo.getWidth();
        int logoHeight = logo.getHeight();

        if (srcWidth == 0 || srcHeight == 0) {
            return null;
        }

        if (logoWidth == 0 || logoHeight == 0) {
            return src;
        }

        //logo大小为二维码整体大小的1/5
        float scaleFactor = srcWidth * 1.0f / 5 / logoWidth;
        Bitmap bitmap = Bitmap.createBitmap(srcWidth, srcHeight, Bitmap.Config.ARGB_8888);
        try {
            Canvas canvas = new Canvas(bitmap);
            canvas.drawBitmap(src, 0, 0, null);
            canvas.scale(scaleFactor, scaleFactor, srcWidth / 2, srcHeight / 2);
            canvas.drawBitmap(logo, (srcWidth - logoWidth) / 2, (srcHeight - logoHeight) / 2, null);

            canvas.save(Canvas.ALL_SAVE_FLAG);
            canvas.restore();
        } catch (Exception e) {
            bitmap = null;
            e.getStackTrace();
        }

        return bitmap;
    }

}

package qrcode.com.qrcodedemo;

import android.content.Context;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;


import java.io.File;

import rx.Observable;
import rx.Observer;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final ImageView imageView = (ImageView) findViewById(R.id.iv_qrcode);
        final String filePath = getFileRoot(MainActivity.this) + File.separator
                + "qr_" + System.currentTimeMillis() + ".jpg";
        //二维码图片较大时，生成图片、保存文件的时间可能较长，因此放在新线程中
        Observable.create(new Observable.OnSubscribe<Boolean>() {
            @Override
            public void call(Subscriber<? super Boolean> subscriber) {
                Boolean success = QRCodeUtils.createQRImage("www.baidu.com".toString().trim(), 800, 800,
                        BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher),
                        filePath);
                subscriber.onNext(success);
                subscriber.onCompleted();
            }
        }).subscribeOn(Schedulers.io()) // 指定 subscribe() 发生在 IO 线程
                .observeOn(AndroidSchedulers.mainThread()) // 指定 Subscriber 的回调发生在主线程
                .subscribe(new Observer<Boolean>() {
                    @Override
                    public void onNext(Boolean success) {
                        if (success) {
                            imageView.setImageBitmap(BitmapFactory.decodeFile(filePath));
                        }
                    }

                    @Override
                    public void onCompleted() {
                    }

                    @Override
                    public void onError(Throwable e) {

                    }
                });

    }

    //文件存储根目录
    private String getFileRoot(Context context) {
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            File external = context.getExternalFilesDir(null);
            if (external != null) {
                return external.getAbsolutePath();
            }
        }

        return context.getFilesDir().getAbsolutePath();
    }
}