處理Asynctask中的遠程異常

Question

這是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 
    }

}

和相關的lastTweet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;
    }
}

所有這些代碼都可以正常工作。 到目前為止，沒有問題。 但是，我想做些小事情。 當HTTP傳輸期間失去連接時，將 引發 RemoteException 且應用程序崩潰 。

我試圖在Async方法中處理異常，但無法做到這一點。

有什么辦法可以處理這樣的異常？

Answer 1

您可以在執行Read AsyncTask之前檢查網絡連接

1.檢查連接

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

2. 設置連接超時

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);