private class AsyncTask extends AsyncTask<String , Integer , Bitmap>{
    private Context mContext;
    private LinearLayout linearLayout;
    Bitmap bit;


    public void setView(LinearLayout ll,Context c){
        linearLayout = ll;
        mContext = c;
    }

    @Override
    protected Bitmap doInBackground(String... params) {
        //執行中 在背景做事情
        for (String urlStr : params) {
            try {
                System.out.println(urlStr);


                InputStream img_stream;
                URL img_url = new URL(urlStr);
                img_stream = img_url.openStream();
                bit = BitmapFactory.decodeStream(img_stream);
            } catch (Exception  e) {
                e.printStackTrace();
            }
            publishProgress();
        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        //執行中 可以在這邊告知使用者進度
        super.onProgressUpdate(values);
        ImageView iv = new ImageView(mContext);
        iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
        iv.setImageBitmap(bit);
        linearLayout.addView(iv);
    }

}