如何在Android应用中实现一个二维码生成功能

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;public class ZXingUtils {    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<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();      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;  }    public static Bitmap creatBarcode(Context context, String contents,                   int desiredWidth, int desiredHeight, boolean displayCode) {    Bitmap ruseltBitmap = null;        int marginW = 20;        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;  }    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) &#63; BLACK : WHITE;      }    }    Bitmap bitmap = Bitmap.createBitmap(width, height,        Bitmap.Config.ARGB_8888);    bitmap.setPixels(pixels, 0, width, 0, 0, width, height);    return bitmap;  }    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;  }    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;  }}ZXingUtils