Good day,

There is a task to get a list of html strings in the Android application. (in PHP, this is solved by simply calling filegetcontent () and you don’t need to think about anything :) I read that this can be done only by creating a separate stream: Android, I can’t get the html page code

Made absolutely separate classes:

class HTMLGet extends AsyncTask<String,Void,Void> { public BufferedReader reader; @Override public void onPreExecute() { //Обновление интерфейса до начала получения html } @Override public Void doInBackground(String... params) { //HTTP запрос try{ URL url = null; url = new URL("http://google.com"); URLConnection con1 = url.openConnection(); BufferedReader reader = new BufferedReader(new InputStreamReader(con1.getInputStream())); } catch (Exception e){ e.printStackTrace(); } return null; } @Override public void onPostExecute(Void result) { //Обновление интерфейса после получения html try{ String line =""; while ((line=reader.readLine())!=null){ System.out.printf(line); } } catch (Exception e){ e.printStackTrace(); } } }

And a description of mainactivity:

 public class MainActivity extends Activity { public void onmyClick(View view) throws IOException { HTMLGet htmlGet = new HTMLGet(); String URL="http://google.com"; //Параметр передаю но пока код его не использует htmlGet.execute(URL); Toast.makeText(this, "Page connect!", Toast.LENGTH_SHORT).show(); view.playSoundEffect(android.view.SoundEffectConstants.CLICK); } }

The project is perfectly compiled on Eclipse but does not give the desired result. nothing is displayed: (in this connection, the question of how to correctly encode a separate stream, where it should be located () relative to MineActivity, to get html strings by url ... and in passing a question that was suggested to me: how to transfer BufferedReader reader inside a class HTMLGet as well as TextEdit3 (from MainActivity) for example in the HTMLGet class that the actually loaded html code is written there (instead of prinf) ...

  • 2
    Your HTMLGet.reader field HTMLGet.reader not initialized (in the doInBackground you create a local variable with the same name), so when it comes to onPostExecute everything dies with NPE. - zRrr

1 answer 1

The solution is to properly manipulate the AsyncTask class. The constructor has 3 parameters, each of which can be used in one of the three main methods. Thus, performing any actions in doInBackGround we must pass information to onPostExecute - this is the main thing. Optionally, you can pass% of the task execution to onProgressUpdate ...