如何添加线程？

Question

本帖的问题正在继续.

我无法想象如何从主UI线程添加单独的线程来执行从服务器收集数据的工作.我之前从未做过线程,我认为我构造的类中的这个实例比我能找到的任何例子都要先进一点.

我的课程的任何帮助和发布的修订将不胜感激.

谢谢!

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Bundle extras = getIntent().getExtras();
        setContentView(R.layout.list_view2);

        /**
         * Get the query string from last activity and pass it to this
         * activity-----------------------------------------------------
         */
        String p = null;
        if (extras != null) {
            p = extras.getString(PHP_KEY);          
        }
        loadQuery(p);
    }

    void loadQuery(String p) {

        String qO = getIntent().getStringExtra("QUERY_ORDER");

        ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
        // http post
        try {

             HttpClient httpclient = new DefaultHttpClient();
             HttpPost httppost = new HttpPost("http://10.0.2.2/App/php/" +
             p + qO + ".php");

            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            is = entity.getContent();

        } catch (Exception e) {
            Log.e("log_tag", "Error in http connection " + e.toString());
        }

        // convert response to string
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            sb = new StringBuilder();
            sb.append(reader.readLine() + "\n");

            String line = "0";
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }

            is.close();
            result = sb.toString();

        } catch (Exception e) {
            Log.e("log_tag", "Error converting result " + e.toString());
        }

        setListAdapter(new QueryAdapter(this, result));
    }

请参阅下面的答案

Answer 1

您应该只使用AsyncTask

这是一个关于如何使用它的教程的好教程

以下是下载网页并将结果返回主UI的示例.

private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {
        String response = "";
        for (String url : urls) {
            DefaultHttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);
            try {
                HttpResponse execute = client.execute(httpGet);
                InputStream content = execute.getEntity().getContent();

                BufferedReader buffer = new BufferedReader(
                        new InputStreamReader(content));
                String s = "";
                while ((s = buffer.readLine()) != null) {
                    response += s;
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return response;
    }

    @Override
    protected void onPostExecute(String result) {
        textView.setText(result);
    }
}