android 根据图片路径获取图片缩略图

    /** 
     * 根据指定的图像路径和大小来获取缩略图 
     * 
     * @param path      图像的路径 
     * @param maxWidth  指定输出图像的宽度 
     * @param maxHeight 指定输出图像的高度 
     * @return 生成的缩略图 
     */  
    public static Bitmap revitionImageSize(String path, int maxWidth, int maxHeight) throws IOException {  
        Bitmap bitmap = null;  
        try {  
            BufferedInputStream in = new BufferedInputStream(new FileInputStream(  
                    new File(path)));  
            BitmapFactory.Options options = new BitmapFactory.Options();  
            options.inJustDecodeBounds = true;  
            BitmapFactory.decodeStream(in, null, options);  
            in.close();  
            int i = 0;  
            while (true) {  
                if ((options.outWidth >> i <= maxWidth)  
                        && (options.outHeight >> i <= maxHeight)) {  
                    in = new BufferedInputStream(  
                            new FileInputStream(new File(path)));  
                    options.inSampleSize = (int) Math.pow(2.0D, i);  
                    options.inJustDecodeBounds = false;  
                    bitmap = BitmapFactory.decodeStream(in, null, options);  
                    break;  
                }  
                i += 1;  
            }  
        } catch (Exception e) {  
            return null;  
        }  
        return bitmap;  
    }