自定义生成二维码，可添加logo

在敲代码之前要记得导入jar包 core-3.2.1.jar 复制百度搜索就可以下载得到

package com.gss.zxingdemo;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.xys.libzxing.zxing.activity.CaptureActivity;

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

public class MainActivity extends AppCompatActivity {

    private ImageView erweima;
    private ImageView img;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        erweima = (ImageView) findViewById(R.id.erweima);
        img = (ImageView) findViewById(R.id.diyerweima);
        //点击按钮吧ip地址生成二维码
        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = generateBitmap("http://blog.youkuaiyun.com/u012702547/article/details/51501350", 400, 400);
                Bitmap bitmap2 = addBackground(bitmap, BitmapFactory.decodeResource(getResources(), R.drawable.background));

                erweima.setImageBitmap(bitmap2);
            }
        });

        //点击生成带logo的二维码
        findViewById(R.id.button2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bitmap bitmap = generateBitmap("孙明亮不是傻逼，孙明亮是臭傻逼", 600, 600);
                Bitmap logo = BitmapFactory.decodeResource(getResources(), R.drawable.jjjj);
                Bitmap bitmap1 = addLogo(bitmap, logo);
                img.setImageBitmap(bitmap1);
            }
        });

    }
    /**
     * 生成二维码
     */
    private Bitmap generateBitmap(String content, int width, int height) {
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        Map<EncodeHintType, String> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        try {
            BitMatrix encode = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, width, height, hints);
            int[] pixels = new int[width * height];
            for (int i = 0; i < height; i++) {
                for (int j = 0; j < width; j++) {
                    if (encode.get(j, i)) {
                        pixels[i * width + j] = 0x00000000;
                    } else {
                        pixels[i * width + j] = 0xffffffff;
                    }
                }
            }
            return Bitmap.createBitmap(pixels, 0, width, width, height, Bitmap.Config.RGB_565);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 给二维码图片加背景
     */
    public static Bitmap addBackground(Bitmap foreground, Bitmap background) {
        int bgWidth = background.getWidth();
        int bgHeight = background.getHeight();
        int fgWidth = foreground.getWidth();
        int fgHeight = foreground.getHeight();
        Bitmap newmap = Bitmap
                .createBitmap(bgWidth, bgHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(newmap);
        canvas.drawBitmap(background, 0, 0, null);
        canvas.drawBitmap(foreground, (bgWidth - fgWidth) / 2,
                (bgHeight - fgHeight) * 3 / 5 + 70, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        canvas.restore();
        return newmap;
    }

    /**
     * 添加图标
     *
     * @param qrBitmap
     * @param logoBitmap
     * @return
     */
    private Bitmap addLogo(Bitmap qrBitmap, Bitmap logoBitmap) {
        int qrBitmapWidth = qrBitmap.getWidth();
        int qrBitmapHeight = qrBitmap.getHeight();
        int logoBitmapWidth = logoBitmap.getWidth();
        int logoBitmapHeight = logoBitmap.getHeight();
        Bitmap blankBitmap = Bitmap.createBitmap(qrBitmapWidth, qrBitmapHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(blankBitmap);
        canvas.drawBitmap(qrBitmap, 0, 0, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        float scaleSize = 1.0f;
        while ((logoBitmapWidth / scaleSize) > (qrBitmapWidth / 5) || (logoBitmapHeight / scaleSize) > (qrBitmapHeight / 5)) {
            scaleSize *= 2;
        }
        float sx = 1.0f / scaleSize;
        canvas.scale(sx, sx, qrBitmapWidth / 2, qrBitmapHeight / 2);
        canvas.drawBitmap(logoBitmap, (qrBitmapWidth - logoBitmapWidth) / 2, (qrBitmapHeight - logoBitmapHeight) / 2, null);
        canvas.restore();
        return blankBitmap;
    }
}

布局的话一个按钮对应一个imageView，二维码是需要imageView来显示的