我用过AsyncTask
,Activity
它给了我想要的结果,没有任何失败。现在我需要使用AsyncTask
with Fragments
。在Fragments
AsyncTask
没有更新 UI。我在这里得到了答案。我在我的代码中尝试了该逻辑,但在从 servlet 获得响应后仍然无法更新 UI。您的帮助将不胜感激。
编写我尝试过的代码:
public class FragmentMyProfile extends Fragment
{
TextView txtViewUserFullName;
SharedPreferences shrdPref;
String currentUserFirstName = "", currentUserEmail = "";
String URL = "http://10.0.2.2:8080/iGnite_Survey/GetUserDetailsServlet";
String jsonObjectReceivedFromServer = "";
public FragmentMyProfile()
{
// empty constructor required for fragment subclass
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View rootView = inflater.inflate(R.layout.fragment_my_profile, container, false);
shrdPref = rootView.getContext().getSharedPreferences("shrdPref", Context.MODE_PRIVATE);
txtViewUserFullName = (TextView) rootView.findViewById(R.id.textViewUserFullName);
//get current user first name, default value is ""
currentUserFirstName = shrdPref.getString(String.valueOf(R.string.curentLoggedInUserFirstName), "");
currentUserEmail = shrdPref.getString(String.valueOf(R.string.curentLoggedInUserEmail), "");
//display current user first name
if(!currentUserFirstName.equals(""))
{
txtViewDisplayUserFirstName.setText("Welcome "+currentUserFirstName);
}
else
{
txtViewDisplayUserFirstName.setText(String.valueOf(R.string.welcomeUser));
}
//get all user details from server
GetUserDetailsAsyncTask getUserDetailsAsyncTask = new GetUserDetailsAsyncTask (new FragmentCallback()
{
@Override
public void onTaskDone(String output)
{
//txtViewUserFullName.setText(output);
}
});
getUserDetailsAsyncTask.execute(new String[] { URL });
return rootView;
}
public interface FragmentCallback
{
public void onTaskDone(String output);
}
//------------------------------------------------------------------------------
public class GetUserDetailsAsyncTask extends AsyncTask<String, Void, String>
{
private FragmentCallback mFragmentCallback;
public GetUserDetailsAsyncTask (FragmentCallback fragmentCallback)
{
mFragmentCallback = fragmentCallback;
}
@Override
protected String doInBackground(String... urls)
{
String output = null;
for (String url : urls)
{
output = sendDataToServer(url);
}
return output;
}
@Override
protected void onPostExecute (String output)
{
super.onPostExecute(output);
mFragmentCallback.onTaskDone();
txtViewUserFullName.setText("output");
}
private String sendDataToServer(String url)
{
String output = null;
try
{
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("user_email", currentUserEmail));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpClient.execute(httpPost);
HttpEntity httpEntity = response.getEntity();
output = EntityUtils.toString(httpEntity);
}
catch (ClientProtocolException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
return output;
}
}
}