java 使用zxing生成二维码,要求二维码上面生成可换行标题

可以使用zxing提供的MultiFormatWriter类来生成二维码。要在二维码上方生成可换行标题，可以使用Bitmap.createBitmap()方法创建一个新的Bitmap对象，并在上面绘制标题和二维码。具体代码如下：

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

public class QRCodeUtil {
    /**
     * 生成带有标题的二维码
     *
     * @param content 二维码内容
     * @param title   标题
     * @param width   二维码宽度
     * @param height  二维码高度
     * @return 带有标题的二维码Bitmap对象
     */
    public static Bitmap createQRCodeWithTitle(String content, String title, int width, int height) {
        try {
            // 生成二维码矩阵
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height);

            // 获取二维码图片的宽高
            int qrCodeWidth = bitMatrix.getWidth();
            int qrCodeHeight = bitMatrix.getHeight();

            // 新建一个Bitmap对象
            Bitmap bitmap = Bitmap.createBitmap(qrCodeWidth, qrCodeHeight + 50, Bitmap.Config.ARGB_8888);

            // 在Bitmap上绘制标题和二维码
            Canvas canvas = new Canvas(bitmap);
            Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
            paint.setTextSize(30);
            paint.setColor(0xff000000);
            Rect bounds = new Rect();
            paint.getTextBounds(title, 0, title.length(), bounds);
            int titleHeight = bounds.height();
            canvas.drawText(title, (qrCodeWidth - bounds.width()) / 2f, titleHeight, paint);
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            BitMatrix qrCodeMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, qrCodeWidth, qrCodeHeight);
            int[] qrCodePixels = new int[qrCodeWidth * qrCodeHeight];
            for (int y = 0; y < qrCodeHeight; y++) {
                int offset = y * qrCodeWidth;
                for (int x = 0; x < qrCodeWidth; x++) {
                    qrCodePixels[offset + x] = bitMatrix.get(x, y) ? 0xff000000 : 0xffffffff;
                }
            }
            bitmap.setPixels(qrCodePixels, 0, qrCodeWidth, 0, titleHeight + 10, qrCodeWidth, qrCodeHeight);
            return bitmap;
        } catch (WriterException e) {
            e.printStackTrace();
            return null;
        }
    }
}

调用方式：

Bitmap bitmap = QRCodeUtil.createQRCodeWithTitle("二维码内容", "标题\n换行", 400, 400);
imageView.setImageBitmap(bitmap);