Question

I’m making HTTP-get requests to the Facebook graph API.

In about 1/5 times my code never gets to Log.i("debug", "resp");. No exception thrown. Shouldn’t it? Or is it just a very long timeout by default?

If I add a custom timeout (see below), I get to throw an exception. But even though my code is wrapped in a try+catch statement, my app crashes (just like on any unhandled exceptions), instead of letting me handle the error in onPostExecute(). Why dont I end up in the method?

protected Map<String, Integer> doInBackground(Void... params) {

    Map<String, Integer> result = new HashMap<String, Integer>();

    try {

        HttpGet get = new HttpGet("https://graph.facebook.com/....etc");

        //final HttpParams httpParams = httpclient.getParams();
        //HttpConnectionParams.setConnectionTimeout(httpParams, 5000);
        //HttpConnectionParams.setSoTimeout(httpParams, 5000);

        HttpResponse response = httpclient.execute(get);
        Log.i("debug", "resp");  

        HttpEntity resEntityGet = response.getEntity();

        //do stuff with resEntityGet           

        return result;            

    } catch (Exception e) { 
        Toast.makeText(mainActivity, "Error: " + ex.getMessage(), Toast.LENGTH_LONG).show();
        return null;
    }
}

protected void onPostExecute(Map<String, Integer> result) {

    if(result != null){
        //use the result data
    } else {
        //exception occured
    }
}

Answer 1

You can show a Toast from the doInBackground method if you post it to the UI thread. There’s a few ways to do it, but here’s one way:

mainActivity.runOnUiThread( new Runnable() {

    @Override
    public void run() {
        Toast.makeText(mainActivity, "Error: " + ex.getMessage(), Toast.LENGTH_LONG).show();
    }
} );

You’ll need to make the Exception variable final