图片二次采样和按质量压缩

图片上传的时候往往需要压缩图片和调整大小

1.二次采样

    /*     *     * 按比例缩放图片大小     *     * @param imageStream     * @compress     * **/    public static Bitmap compressImageProportion(String srcPath, int height, int width) {        if (null == srcPath || "".equals(srcPath.trim())) {            return null;        }        BitmapFactory.Options newOpts = new BitmapFactory.Options();        //开始读入图片，此时把options.inJustDecodeBounds 设回true了        newOpts.inJustDecodeBounds = true;        Bitmap bitmap = BitmapFactory.decodeFile(srcPath, newOpts);//此时返回bm为空        int w = newOpts.outWidth;        int h = newOpts.outHeight;        //现在主流手机比较多是800*480分辨率，所以高和宽我们设置为        float hh = height;//这里设置高度为800f        float ww = width;//这里设置宽度为480f        //缩放比。由于是固定比例缩放，只用高或者宽其中一个数据进行计算即可        int be = 1;//be=1表示不缩放        if ( w > ww) {//如果宽度大的话根据宽度固定大小缩放            be = (int) (newOpts.outWidth / ww);        }        if (be <= 0)            be = 1;        newOpts.inSampleSize = be;//设置缩放比例        newOpts.inJustDecodeBounds = false;        //重新读入图片，注意此时已经把options.inJustDecodeBounds 设回false了        bitmap = BitmapFactory.decodeFile(srcPath, newOpts);        return bitmap;    }

按照宽度的比例进行缩放

2.质量压缩

    /*     *     * 按质量压缩图片大小     *     * @param image     * @compress     * **/    public static InputStream compressImage(Bitmap image, int compress) {        if (image != null) {            ByteArrayOutputStream baos = new ByteArrayOutputStream();            image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中            int options = 100;            Log.e("compressImage: ", baos.toByteArray().length / 1024 + "," + compress);            while (baos.toByteArray().length / 1024 > compress) {  //循环判断如果压缩后图片是否大于compressValue kb,大于继续压缩                baos.reset();//重置baos即清空baos                image.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中                options -= 10;//每次都减少10                if (options < 0) {                    break;                }            }            ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中            return isBm;        }        return null;    }    //压缩图片大小返回图片    public static Bitmap compressImagebp(Bitmap image, int compress) {        return BitmapFactory.decodeStream(compressImage(image,compress), null, null);    }

3.以上两种方法的使用

        bt1.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Bitmap bitmap = BitmapUtils.getbitmap("/sdcard/img.jpg");                int compress = seekBar1.getProgress();                Bitmap bitmap1 = BitmapUtils.compressImagebp(bitmap, compress);                Log.e( "onClick: ",bitmap.getByteCount()+","+bitmap1.getByteCount() );                iv.setImageBitmap(bitmap1);            }        });        bt2.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Bitmap bitmap = BitmapUtils.getbitmap("/sdcard/img.jpg");                int width = bitmap.getWidth();                int height=  bitmap.getHeight();                float compress = seekBar2.getProgress()/100f;                Log.e( "onClick: ",compress+"" );               /* Bitmap bitmap1 = bitmap.copy(Bitmap.Config.ARGB_8888, true);                bitmap1.setWidth(((int) (compress * width)));                bitmap1.setHeight(((int) (compress * height)));*/              Bitmap bitmap1 = BitmapUtils.compressImageProportion("/sdcard/img.jpg", ((int) (compress * width)), ((int) (compress * height)));                iv.setImageBitmap(bitmap1);            }        });