ZXing创建二维码位图

Android生成二维码通常使用ZXing库，其中提供了QRCodeWriter类。QRCodeWriter可将字符串编译为位矩阵BitMatrix，然后我们可以将位矩阵转为Int数组，通过bitmap.setPixels()方法将数组绘制于位图上。

1. 添加依赖

//Gradle Scripts -> build.gradle(Module:app)
implementation 'com.google.zxing:core:3.4.1'
implementation 'com.journeyapps:zxing-android-embedded:4.2.0'

2. 工具类

import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.Matrix;
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.util.HashMap;
import java.util.Map;public class QRCodeUtils {/*** 根据文本与容错值生成二维码位图* @param text 文本* @param errorCorrectionLevel 容错值* @return 返回位图，如无文本内容返回null*/public Bitmap getQRBitmap(String text, ErrorCorrectionLevel errorCorrectionLevel) {if(text==null){return null;}//错误值if(errorCorrectionLevel==null){errorCorrectionLevel=ErrorCorrectionLevel.H;}int width = text.length() * 6; // 二维码图片的宽度if(errorCorrectionLevel==ErrorCorrectionLevel.L){width= (int) (width*1.5);}else if(errorCorrectionLevel==ErrorCorrectionLevel.Q){width= (int) (width*2);}else if(errorCorrectionLevel==ErrorCorrectionLevel.M){width= (int) (width*3);}else if(errorCorrectionLevel==ErrorCorrectionLevel.H){width= (int) (width*4);}int height = width; // 二维码图片的高度int margin = 1; // 二维码图片的空白边距Map<EncodeHintType, Object> hints = new HashMap<>();hints.put(EncodeHintType.MARGIN, margin); // 设置空白边距hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); // 设置字符编码格式hints.put(EncodeHintType.ERROR_CORRECTION, errorCorrectionLevel); // 设置容错率try {// 根据配置参数生成位矩阵对象BitMatrix bitMatrix = new QRCodeWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);// 创建像素数组，并根据位矩阵对象为数组元素赋色值int[] pixels = new int[width * height];for (int y = 0; y < height; y++) {for (int x = 0; x < width; x++) {if (bitMatrix.get(x, y)) { // 返回true表示黑色色块pixels[y * width + x] = Color.BLACK;} else { // 返回false表示白色色块pixels[y * width + x] = Color.WHITE;}}}// 创建位图对象，并根据像素数组设置每个像素的色值Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);bitmap.setPixels(pixels, 0, width, 0, 0, width, height);//过小放大if(width<500){float i=500/width;Matrix matrix=new Matrix();matrix.setScale(i,i);bitmap= Bitmap.createBitmap(bitmap,0,0,width,height,matrix,false);}return bitmap;} catch (WriterException e) {e.printStackTrace();return  null;}}
}