设置自动旋转屏幕方向的问题

我想设置禁止自动旋转屏幕方向。还有能够自动选择屏幕的方向的功能。如何实现？

class NewLoad extends AsyncTask<String, String, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progDailog = new ProgressDialog(this);
            progDailog.setMessage("test");
            progDailog.setIndeterminate(false);
            progDailog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            progDailog.setCancelable(false);
            progDailog.show();
            //set disable auto change
        }

        @Override
        protected String doInBackground(String... aurl) {
            //do something
            return null;
        }

        @Override
        protected void onPostExecute(String unused) {
            super.onPostExecute(unused);
            progDailog.dismiss();
            //set enable auto change
        }
    }

配置文件中对Activity节点添加android:screenOrientation属性(landscape是横向，portrait是纵向)，
代码里强制设置如横屏
if(getRequestedOrientation()!=ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE){
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}