andorid通过代码让url转换成二维码，很常用。

1.android 有自带的jar包可以生成二维码core-3.0.0.jar，其中的com.google.zxing包

2.写一个二维码生成的工具类，网上搜的话应该一大堆。

package com.example.administrator.twocodedemo;  

import android.content.Context;  
import android.graphics.Bitmap;  
import android.graphics.Bitmap.Config;  
import android.graphics.Canvas;  
import android.graphics.Color;  
import android.graphics.PointF;  
import android.view.Gravity;  
import android.view.View.MeasureSpec;  
import android.widget.LinearLayout;  
import android.widget.LinearLayout.LayoutParams;  
import android.widget.TextView;  

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 java.util.Hashtable;  

/**   
*  
*   生成条形码和二维码的工具  
*/  
public class ZXingUtils {  
    /**  
     * 生成二维码 要转换的地址或字符串,可以是中文  
     *   
     * @param url  
     * @param width  
     * @param height  
     * @return  
     */  
    public static Bitmap createQRImage(String url, final int width, final int height) {  
        try {  
            // 判断URL合法性  
            if (url == null || "".equals(url) || url.length() < 1) {  
                return null;  
            }  
            Hashtable hints = new Hashtable();  
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");  
            // 图像数据转换，使用了矩阵转换  
            BitMatrix bitMatrix = new QRCodeWriter().encode(url,  
                    BarcodeFormat.QR_CODE, width, height, hints);  
            int[] pixels = new int[width * height];  
            // 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 < height; y++) {  
                for (int x = 0; x < width; x++) {  
                    if (bitMatrix.get(x, y)) {  
                        pixels[y * width + x] = 0xff000000;  
                    } else {  
                        pixels[y * width + x] = 0xffffffff;  
                    }  
                }  
            }  
            // 生成二维码图片的格式，使用ARGB_8888  
            Bitmap bitmap = Bitmap.createBitmap(width, height,  
                    Bitmap.Config.ARGB_8888);  
            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);  
            return bitmap;  
        } catch (WriterException e) {  
            e.printStackTrace();  
        }  
        return null;  
    }  

    /**  
     * 生成条形码  
     *  
     * @param context  
     * @param contents  
     *            需要生成的内容  
     * @param desiredWidth  
     *            生成条形码的宽带  
     * @param desiredHeight  
     *            生成条形码的高度  
     * @param displayCode  
     *            是否在条形码下方显示内容  
     * @return  
     */  
    public static Bitmap creatBarcode(Context context, String contents,  
                                      int desiredWidth, int desiredHeight, boolean displayCode) {  
        Bitmap ruseltBitmap = null;  
        /**  
         * 图片两端所保留的空白的宽度  
         */  
        int marginW = 20;  
        /**  
         * 条形码的编码类型  
         */  
        BarcodeFormat barcodeFormat = BarcodeFormat.CODE_128;  

        if (displayCode) {  
            Bitmap barcodeBitmap = encodeAsBitmap(contents, barcodeFormat,  
                    desiredWidth, desiredHeight);  
            Bitmap codeBitmap = creatCodeBitmap(contents, desiredWidth + 2  
                    * marginW, desiredHeight, context);  
            ruseltBitmap = mixtureBitmap(barcodeBitmap, codeBitmap, new PointF(  
                    0, desiredHeight));  
        } else {  
            ruseltBitmap = encodeAsBitmap(contents, barcodeFormat,  
                    desiredWidth, desiredHeight);  
        }  

        return ruseltBitmap;  
    }  

    /**  
     * 生成条形码的Bitmap  
     *  
     * @param contents  
     *            需要生成的内容  
     * @param format  
     *            编码格式  
     * @param desiredWidth  
     * @param desiredHeight  
     * @return  
     * @throws WriterException  
     */  
    protected static Bitmap encodeAsBitmap(String contents,  
                                           BarcodeFormat format, int desiredWidth, int desiredHeight) {  
        final int WHITE = 0xFFFFFFFF;  
        final int BLACK = 0xFF000000;  

        MultiFormatWriter writer = new MultiFormatWriter();  
        BitMatrix result = null;  
        try {  
            result = writer.encode(contents, format, desiredWidth,  
                    desiredHeight, null);  
        } catch (WriterException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  

        int width = result.getWidth();  
        int height = result.getHeight();  
        int[] pixels = new int[width * height];  
        // All are 0, or black, by default  
        for (int y = 0; y < height; y++) {  
            int offset = y * width;  
            for (int x = 0; x < width; x++) {  
                pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;  
            }  
        }  

        Bitmap bitmap = Bitmap.createBitmap(width, height,  
                Bitmap.Config.ARGB_8888);  
        bitmap.setPixels(pixels, 0, width, 0, 0, width, height);  
        return bitmap;  
    }  

    /**  
     * 生成显示编码的Bitmap  
     *  
     * @param contents  
     * @param width  
     * @param height  
     * @param context  
     * @return  
     */  
    protected static Bitmap creatCodeBitmap(String contents, int width,  
                                            int height, Context context) {  
        TextView tv = new TextView(context);  
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(  
                LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);  
        tv.setLayoutParams(layoutParams);  
        tv.setText(contents);  
        tv.setHeight(height);  
        tv.setGravity(Gravity.CENTER_HORIZONTAL);  
        tv.setWidth(width);  
        tv.setDrawingCacheEnabled(true);  
        tv.setTextColor(Color.BLACK);  
        tv.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),  
                MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));  
        tv.layout(0, 0, tv.getMeasuredWidth(), tv.getMeasuredHeight());  

        tv.buildDrawingCache();  
        Bitmap bitmapCode = tv.getDrawingCache();  
        return bitmapCode;  
    }  

    /**  
     * 将两个Bitmap合并成一个  
     *   
     * @param first  
     * @param second  
     * @param fromPoint  
     *            第二个Bitmap开始绘制的起始位置（相对于第一个Bitmap）  
     * @return  
     */  
    protected static Bitmap mixtureBitmap(Bitmap first, Bitmap second,  
                                          PointF fromPoint) {  
        if (first == null || second == null || fromPoint == null) {  
            return null;  
        }  
        int marginW = 20;  
        Bitmap newBitmap = Bitmap.createBitmap(  
                first.getWidth() + second.getWidth() + marginW,  
                first.getHeight() + second.getHeight(), Config.ARGB_4444);  
        Canvas cv = new Canvas(newBitmap);  
        cv.drawBitmap(first, marginW, 0, null);  
        cv.drawBitmap(second, fromPoint.x, fromPoint.y, null);  
        cv.save(Canvas.ALL_SAVE_FLAG);  
        cv.restore();  

        return newBitmap;  
    }  

} 

准备工作完成，现在可以在用到的地方使用，我们这里就在MainActivity中

package com.example.administrator.twocodedemo;  

import android.graphics.Bitmap;  
import android.os.Bundle;  
import android.support.v7.app.AppCompatActivity;  
import android.view.View;  
import android.widget.Button;  
import android.widget.EditText;  
import android.widget.ImageView;  

import butterknife.BindView;  
import butterknife.ButterKnife;  
import butterknife.OnClick;  

public class MainActivity extends AppCompatActivity {  

    @BindView(R.id.et_url)  
    EditText etUrl;  
    @BindView(R.id.btn_create)  
    Button btnCreate;  
    @BindView(R.id.iv_two_code)  
    ImageView ivTwoCode;  

    private String imagePath;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        ButterKnife.bind(this);  
    }  


    @OnClick({R.id.btn_create, R.id.iv_two_code})  
    public void onClick(View view) {  
        switch (view.getId()) {  
            case R.id.btn_create:  

                String url = etUrl.getText().toString().trim();  
                Bitmap bitmap = ZXingUtils.createQRImage(url, ivTwoCode.getWidth(), ivTwoCode.getHeight());  
                ivTwoCode.setImageBitmap(bitmap);  

这其中使用了Butterknife注解工具，其中真正的代码就两句：

Bitmap bitmap = ZXingUtils.createQRImage(url, ivTwoCode.getWidth(), ivTwoCode.getHeight());  
                ivTwoCode.setImageBitmap(bitmap); 

下载地址:
https://download.csdn.net/download/coder_yao/9605324