start asynchtask oncreate after recognizing asynchtask

Question

public class MainActivity extends Activity {
TextView statustv = (TextView) findViewById(R.id.status);;
ProgressDialog pd;
String status, url = "http://wvde.state.wv.us/closings/county/monongalia";

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

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

private class School extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd = new ProgressDialog(MainActivity.this);
        pd.setTitle("Android Basic JSoup Tutorial");
        pd.setMessage("Loading...");
        pd.setIndeterminate(false);
        pd.show();
    }

    @Override
    protected Void doInBackground(Void... params) {

        try {
            Document doc = Jsoup.connect(url).get();
            Elements table = doc.select("td#content_body");
            status = table.select("table").text();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        statustv.setText(status);
        pd.dismiss();
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_refresh) {
        new School().execute();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}

How can I have new School().execute(); happen oncreate without getting a nullpointer error because right now when oncreate executes it executes new School().execute(); before it even knows what the asynchtask is. How can i have it execute correctly oncreate?

score 0 · Accepted Answer · edited May 23 '17 at 10:26

0

You can post a runnable to the current thread's handler. The runnable starts the AsyncTask. Here is an easy example of using handler: https://stackoverflow.com/a/1921759/1843698

Official Doc for Handler: http://developer.android.com/reference/android/os/Handler.html The handler schedule a task (your runnable) in current thread, and your task will be executed later in the same thread as soon as possible, but it will be executed after onCreate() finishes.

edited May 23 '17 at 10:26

Community

1
1

answered Jul 14 '14 at 00:31

Kaifei

1,568
2
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When I tried that I got an error "Cannot make a static reference to the non-static method postDelayed(Runnable, long) from the type Handler" – Hasan Jul 14 '14 at 15:45
You should initialize a handler: *Handler handler = new Handler();* Then call *handler.postDelayed()*. Handler is the class, and handler is one instance of it. Ref: http://stackoverflow.com/a/6550537/1843698 – Kaifei Jul 14 '14 at 19:49

start asynchtask oncreate after recognizing asynchtask

1 Answers1