NetworkOnMainThreadException但使用AsyncTask

Question

我编写了一个类,它启动一个http连接来获取例如网站的文本.我使用AsyncTask但我得到了NetworkOnMainException.你能救我吗？班级

public class getXMLData extends AsyncTask<String, Void, String> {
TextView _textview;

public getXMLData(TextView textview) {
    _textview = textview;
}

protected String doInBackground(String... url)
{
    String _text = "";
    try {
        try {
            URL _url = new URL(url[0]);
            HttpURLConnection con = (HttpURLConnection) _url.openConnection();
            _text = readStream(con.getInputStream());
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
    catch (Exception e) {
        e.printStackTrace();
    }
    return _text;
}

protected void onPostExecute(String result)
{
    _textview.setText(result.toCharArray(), 0, result.length());
}


private String readStream(java.io.InputStream in) {
    java.io.BufferedReader reader = null;
    String result = "";
    reader = new BufferedReader(new InputStreamReader(in));
    try {
        while ((reader.readLine() != null)) {
            result = result + reader.readLine();
        }
    }
    catch (java.io.IOException i)
    {

    }
    finally
    {
        try {
            reader.close();
        }
        catch (java.io.IOException e) {
            e.printStackTrace();
        }
    }
    return result;
}

我在这里如何启动AsyncTask:

bu_aktualize.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
          _getXMLData.doInBackground("http://www.google.de");

        }
    });

谢谢你的帮助.

Answer 1

你不打电话给doInBackground()自己.相反,你打电话execute()或executeOnExecutor()开始AsyncTask.

您可能希望查看文档AsyncTask,其中显示了设置的示例AsyncTask,包括对其的调用execute().