HTTP POST请求适用于模拟器，但不适用于实际设备

Question

我构建了一个简单的应用程序，它使用HTTP POST请求从远程数据库获取数据。我决定改变它的布局，但现在我意识到的请求在真实设备上不起作用。

我只需更改布局并在此新项目中复制相同的类。我无法理解什么是错的。当我使用该应用程序时，它会在启动画面活动中停止并等待。我查看了代码，我注意到我在执行POST请求时停止了。 当我在仿真器上执行项目时，它可以很好地工作。

这是我的班级：

public class MyHttpPostRequest extends AsyncTask<String, Void, String[]> {

private String link;
private String querySql;

public MyHttpPostRequest(String remoteLink, String richiestaSql) {
    this.link = remoteLink;
    this.querySql = richiestaSql;
}

@Override
protected String[] doInBackground(String... params) {

    // Create a new HttpClient and Post Header
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost request = new HttpPost(this.link);

    BufferedReader bufferedReader = null;
    List<NameValuePair> postParameters = new ArrayList<NameValuePair>();
    postParameters.add(new BasicNameValuePair("query", this.querySql));

    StringBuffer stringBuffer = null;

    String[] token = new String[600];

    try {
        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postParameters);
        request.setEntity(entity);

        HttpResponse response= httpClient.execute(request);

        bufferedReader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        stringBuffer = new StringBuffer("");
        String line = "";
        String LineSeparator = System.getProperty("line.separator");
        int i=0;
        while ((line = bufferedReader.readLine()) != null) {
            stringBuffer.append(line + LineSeparator); 
            token[i] = line + LineSeparator;
            i++;
        }
        bufferedReader.close();
    } catch(Exception e){

    }

    return token;
}

@Override
protected void onPostExecute(String[] result) {
    super.onPostExecute(result);
}

public void eseguiRichiesta(){
    this.execute(this.link, this.querySql);
}

public void setValues(String remoteLink, String richiestaSql){
    this.link = remoteLink;
    this.querySql = richiestaSql;
}   

public void setLink(String link){
    this.link = link;
}

public void setRequest(String requestSQL){
    this.querySql = requestSQL;
}
}