在android中实现两张图片对比

package  com.xupp.sxjiesuo;

import  java.text.DecimalFormat;

import  android.R.integer;
import  android.graphics.Bitmap;
import  android.graphics.BitmapFactory;

/**
 * Android图片对比(像素精准对比),速度较慢建议用多线程获取
 * @author xupp
 * @createData 2013-7-18
 */

public  class  PictureContrast {
    private  static  int  t =  0 ;
    private  static  int  f =  0 ;
    public  static  String similarity (String url_one,String url_two) {
        //把图片转换为Bitmap
        Bitmap bm_one = BitmapFactory.decodeFile(url_one);
        Bitmap bm_two = BitmapFactory.decodeFile(url_two);
        //保存图片所有像素个数的数组，图片宽×高
        int [] pixels_one =  new  int [bm_one.getWidth()*bm_one.getHeight()];
        int [] pixels_two =  new  int [bm_two.getWidth()*bm_two.getHeight()];
        //获取每个像素的RGB值
        bm_one.getPixels(pixels_one, 0 ,bm_one.getWidth(), 0 , 0 ,bm_one.getWidth(),bm_one.getHeight());
        bm_two.getPixels(pixels_two, 0 ,bm_two.getWidth(), 0 , 0 ,bm_two.getWidth(),bm_two.getHeight());
        //如果图片一个像素大于图片2的像素，就用像素少的作为循环条件。避免报错
        if  (pixels_one.length >= pixels_two.length) {
            //对每一个像素的RGB值进行比较
            for ( int  i =  0 ; i < pixels_two.length; i++){
                int  clr_one = pixels_one[i];
                int  clr_two = pixels_two[i];
                //RGB值一样就加一（以便算百分比）
                if  (clr_one == clr_two) {
                    t++;
                } else  {
                    f++;
                   }
            }
        } else  {
            for ( int  i =  0 ; i < pixels_one.length; i++){
                int  clr_one = pixels_one[i];
                int  clr_two = pixels_two[i];
                if  (clr_one == clr_two) {
                    t++;
                } else  {
                    f++;
                }
            }

        }

        return  "相似度为：" +myPercent(t,t+f);

    }
    /**
     * 百分比的计算
     * @author xupp
     * @param y(母子)
     * @param z（分子）
     * @return 百分比（保留小数点后两位）
     */
    public  static  String myPercent( int  y, int  z)
    {
        String baifenbi= "" ; //接受百分比的值
         double  baiy=y* 1.0 ;
        double  baiz=z* 1.0 ;
        double  fen=baiy/baiz;
        DecimalFormat df1 =  new  DecimalFormat( "00.00%" );  //##.00%   百分比格式，后面不足2位的用0补齐
        baifenbi= df1.format(fen);
        return  baifenbi;
    }

}