生成二維碼（帶Logo和不帶logo的二維碼）

1、用的二維碼庫是：zxing_core_3.3.1.jar；

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.util.Log;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
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.util.HashMap;
import java.util.Map;

/**
 * created by cy on 2020/7/8 0008.
 */
public class QRCodeUtils {
    private static final String TAG = "QRCodeUtils";

    /**
     * 創建二維碼
     *
     * @param content   content
     * @param widthPix  widthPix
     * @param heightPix heightPix
     * @param logoBm    logoBm
     * @return 二維碼
     */
    public static Bitmap createQRCode(String content, int widthPix, int heightPix, Bitmap logoBm) {
        try {
            if (content == null || "".equals(content)) {
                return null;
            }
            // 配置引數
            Map<EncodeHintType, Object> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            // 容錯級別
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            // 設定空白邊距的寬度
            hints.put(EncodeHintType.MARGIN, 0);
            // 影像資料轉換，使用了矩陣轉換
            BitMatrix bitMatrix = new QRCodeWriter().encode(content, BarcodeFormat.QR_CODE, widthPix,
                    heightPix, hints);
            int[] pixels = new int[widthPix * heightPix];
            // 下面這里按照二維碼的演算法，逐個生成二維碼的圖片，
            // 兩個for回圈是圖片橫列掃描的結果
            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;
                    }
                }
            }
            // 生成二維碼圖片的格式，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);
            }
            //必須使用compress方法將bitmap保存到檔案中再進行讀取，直接回傳的bitmap是沒有任何壓縮的，記憶體消耗巨大！
            return bitmap;
        } catch (WriterException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 在二維碼中間添加Logo圖案
     */
    private static Bitmap addLogo(Bitmap src, Bitmap logo) {
        if (src == null) {
            return null;
        }
        if (logo == null) {
            return src;
        }
        //獲取圖片的寬高
        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大小為二維碼整體大小的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.restore();
        } catch (Exception e) {
            bitmap = null;
            e.getStackTrace();
        }
        return bitmap;
    }

    /**
     * 用字串生成二維碼
     */
    public static Bitmap Create2DCode(String str, int width, int height) {
        // 生成二維矩陣,編碼時指定大小,不要生成了圖片以后再進行縮放,這樣會模糊導致識別失敗
        BitMatrix matrix;
        Bitmap bitmap = null;
        try {
            Map<EncodeHintType, Object> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            // 容錯級別
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            // 設定空白邊距的寬度
            hints.put(EncodeHintType.MARGIN, 0);

            matrix = new MultiFormatWriter().encode(str, BarcodeFormat.QR_CODE, width, height, hints);
            // int realWidth = matrix.getWidth();
            // int realHeight = matrix.getHeight();
            Log.i(TAG, " matrix.getWidth() == " + matrix.getWidth());
            Log.i(TAG, " matrix.getHeight() == " + matrix.getHeight());
            // 二維矩陣轉為一維像素陣列,也就是一直橫著排了
            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] = 0xff000000;
                    }
                }
            }
            Log.i(TAG, "width == " + width);
            Log.i(TAG, "height == " + height);
            bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
            // 通過像素陣列生成bitmap,具體參考api
            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);

        } catch (WriterException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return bitmap;
    }
}