Asynctask卡住了

Question

我正在尝试开发Android应用程序。每次应用程序启动时，都必须从服务器获取一些详细信息。我使用了asynctask，我在android中的onCreate方法中调用它。它在服务器运行时非常有效，但是当服务器没有运行时，我不希望我的应用程序挂起等待超时并发现服务器没有运行。什么是更好的实施方式？在我目前的方法中，应用程序一直停留，直到超时发生。

Answer 1

您可以使用以下代码

为HttpURLConnection添加提示

urlConnection.setReadTimeout(10000);
urlConnection.setConnectTimeout(15000);

完整源代码如下。干杯：）

 public class MainActivity extends AppCompatActivity {

             @Override
             protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_main);
              new Test().execute();
             }


             //AsyncTask 
             class Test extends AsyncTask < String, Void, String > {

              @Override
              protected String doInBackground(String...params) {
               InputStream in = null;
               String queryResult = "";
               URL url = new URL("http://www.android.com/");
               HttpURLConnection urlConnection = (HttpURLConnection)          url.openConnection();

              //add parameters
              urlConnection.setReadTimeout(10000);
              urlConnection.setConnectTimeout(15000);
              urlConnection.setRequestMethod("POST");
              urlConnection.setDoInput(true);
              urlConnection.setDoOutput(true);

             List<NameValuePair> params = new ArrayList<NameValuePair>();
             params.add(new BasicNameValuePair("firstParam", paramValue1));
             params.add(new BasicNameValuePair("secondParam", paramValue2));
             params.add(new BasicNameValuePair("thirdParam", paramValue3));
               try {
            //write OutputStream
            OutputStream os = urlConnection.getOutputStream();
            BufferedWriter writer = new BufferedWriter(
                    new OutputStreamWriter(os, "UTF-8"));
            writer.write(getQuery(params));
            writer.flush();
            writer.close();
            os.close();


                InputStream in = new     BufferedInputStream(urlConnection.getInputStream());
                queryResult = readStream( in );
               } finally {
                urlConnection.disconnect();
               }
               return queryResult;

              }
              private String readStream(InputStream iStream) throws IOException {

               //Buffered reader allows us to read line by line
               try (BufferedReader bReader =
                new BufferedReader(new InputStreamReader(iStream))) {
                StringBuilder builder = new StringBuilder();
                String line;
                while ((line = bReader.readLine()) != null) { //Read till end
                 builder.append(line);
                }
                return builder.toString();
               }
              }
            private String getQuery(List<NameValuePair> params) throws   UnsupportedEncodingException
            {
                StringBuilder result = new StringBuilder();
                boolean first = true;

                for (NameValuePair pair : params)
                {
                    if (first)
                        first = false;
                    else
                        result.append("&");

                    result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
                    result.append("=");
                    result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
                }

                return result.toString();
            }
              protected void onPostExecute(String data) {
               // do further things 
               Toast toast = Toast.makeText(getApplicationContext(), data,
                Toast.LENGTH_SHORT);
               toast.show();

              }

             }

            }

Answer 2

使用下面一行代码：

 try {
        URL url = new URL("http://192.168.1.1");   
        HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
        urlc.setConnectTimeout(5 * 1000);
        urlc.connect();
        if (urlc.getResponseCode() == 200) {    
        // condition for connection is fine , 200 = "OK" 
            return true;
        } else {
            return false;
        }
    } catch (MalformedURLException e1) {
        return false;
    } catch (IOException e) {
        return false;
    }

Answer 3

当我更改为asyncTask.execute().get();时，我正在使用asyncTask.execute()它工作正常