网络地址图片二次采样(HttpURLConnection)

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    /*     img即你要获得图片的控件     path即你要从网络上获取的图片     destHight你要采样的图片高度     deWeight你要采样的图片宽度    */private void loadImage( ImageView img, String path, final int destHight, final int destWeight) {    new AsyncTask<String, Void, Bitmap>() {        @Override        protected void onPostExecute(Bitmap bitmap) {            super.onPostExecute(bitmap);            if (bitmap != null)                img.setImageBitmap(bitmap);            else                img.setImageResource(R.mipmap.ic_launcher);        }        @Override        protected Bitmap doInBackground(String... params) {            try {                String path = params[0];                URL url = new URL(path);                HttpURLConnection connection = (HttpURLConnection) url.openConnection();                connection.setRequestMethod("GET");                connection.setConnectTimeout(5000);                connection.setReadTimeout(5000);                int code = connection.getResponseCode();                if (code == 200) {                    //得到图片数据                    InputStream is = connection.getInputStream();                    //BitmapFactory.decodeStream(is);//ARGB_888 一个像素占 4个字节  ARGB_565 一个像素占 2 个字节  Alpha Red、Green、Blue(颜色)                    BitmapFactory.Options options = new BitmapFactory.Options();                    //在图片真正解析之前，不要解析图片数据，只需要告诉一下转换器，只要获取图片的像素(宽高)                    options.inJustDecodeBounds = true;//告诉BitmapFactory转换工厂不去真正解析图片只需要拿到图片宽高就行                    //假解析 API 有bug                    BitmapFactory.decodeStream(is, null, options);                    //压缩，根据图片采样率进行二次采样   100 * 100 是你所期望的具体图片尺寸                    //options.inSampleSize = 2; //采样用来计算图片的宽高(1920 * 1080 -> 1920 / 2 1080 / 2)                    //获取图片宽高，注意：图片的原始宽高                    int width = options.outWidth;                    int height = options.outHeight;                    System.out.println("宽:" + width + "高 ： " + height);                    //定义一个变量去记住我们采样率                    int inSampleSize = 1;//默认是1 ,即不对图片进行任何压缩                    if (width > destWeight || height > destHight) {                        int halfWidth = width / 2;                        int halfHeight = height / 2;                        while ((halfWidth / inSampleSize) >= destWeight && (halfHeight / inSampleSize) >= destHight) {                            //计算采样率                            inSampleSize *= 2;                        }                    }                    //采样率改变了                    options.inSampleSize = inSampleSize;// 8                    //图片压缩完之后，放行图片解析                    options.inJustDecodeBounds = false;//告诉图片转换工厂，可以解析图片了                    //关闭之前的流                    is.close();                    //重新再去得到当前这张图片的字节流数据                    is = url.openStream();                    //开始解析图片                    Bitmap bitmap = BitmapFactory.decodeStream(is, null, options);                    //关闭流                    is.close();                    // Bitmap bitmap = BitmapFactory.decodeStream(is);                    return bitmap;                }            } catch (Exception e) {                e.printStackTrace();            }            return null;        }    }.execute(path);}
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