在Asynctask中处理远程异常

Question

以下是Asynctask方法：

public class Read extends AsyncTask<String, Integer, String> {
    ProgressDialog dialog;
    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
    }
    @Override
    protected String doInBackground(String... params) {
        // TODO Auto-generated method stub
        try {
            sUrl = sUrl.trim();
            json = lastTweet(sUrl);
            return json.getString(params[0]);
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub 
    }
}

以及相关的最后一条推文方法：

public JSONObject lastTweet(String username)
        throws ClientProtocolException, IOException, JSONException {
    HttpGet get = new HttpGet(url.toString());
    HttpResponse r = client.execute(get);
    int status = r.getStatusLine().getStatusCode();
    if (status == 200) {
        HttpEntity e = r.getEntity();
        String data = EntityUtils.toString(e);
        JSONArray timeline = new JSONArray(data);
        JSONObject last = timeline.getJSONObject(0);
        return last;
    }
}

所有这些代码都运行良好。截至目前没有任何问题。然而，我想做一些小的修改。当HTTP传输过程中连接丢失时，会抛出RemoteException并导致应用程序崩溃。

我试图在Async方法中处理异常，但没能做到

有什么方法可以处理这样的异常吗？

Answer 1

您可以在执行Read AsyncTask 之前检查网络连接

1.检查连接

if(ifConnectionIsAvailable)
    new Read().execute();

2.设置连接超时

HttpGet get = new HttpGet(url.toString());
HttpParams httpParameters = new BasicHttpParams();
int timeoutConnection = 3000;// in milliseconds 
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
int timeoutSocket = 5000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
HttpResponse r = httpClient.execute(get);