如果没有可用的互联网连接，则我的应用中存在ANR

Question

I am having a little problem, I can connect to internet and read an url easily. but if no internet connection is available I get ANR and my app is force closed ! Any help ?

    try {
        URL Url = new URL(url); 
        HttpURLConnection httpCon = (HttpURLConnection) Url.openConnection();


        httpCon.setRequestMethod("GET");
        //httpCon.setReadTimeout(2000);
        Log.v("Parser","before connect");
        //httpCon.connect(); 
        int response;
            response = httpCon.getResponseCode();

        } catch (Exception urlExc) {
            Log.v("Parser","into parser error" + urlExc.getCause());
            return false;
        }

When no connection available, it is forced closed instead of going to catch()

Answer 1

Are you doing this in the main UI thread? If so, don't. Investigate one of the many ways of using background threads.

See this Painless Threading article for a discussion. It says:

Specifically, if everything is happening in a single thread, performing long operations such as network access or database queries on the UI thread will block the whole user interface. No event can be dispatched, including drawing events, while the long operation is underway. From the user's perspective, the application appears hung. Even worse, if the UI thread is blocked for more than a few seconds (about 5 seconds currently) the user is presented with the infamous "application not responding" (ANR) dialog.

( ASyncTask might be a good starting point.)