java - How can I change the ActionBar color after AsyncTask? -

in app i'm performing asynctask in onpagefinished attached webview. method looks this:

@override public void onpagefinished(webview mywebview, string url) {     new sendrequestasynctask().execute();      // when page has finished loading dismiss progress dialog     if (progressdialog != null && progressdialog.isshowing())     {         progressdialog.dismiss();     } } 

and sendrequestasynctask looks this:

public class sendrequestasynctask extends asynctask <void, void, void> {      @override     protected void onpreexecute() {         // todo auto-generated method stub         super.onpreexecute();         //runs in ui thread     }      @override     protected void doinbackground(void... params) {         // todo auto-generated method stub          httpclient httpclient = new defaulthttpclient();         httppost httppost = new httppost("myscript.php");          try {             // add data             list<namevaluepair> namevaluepairs = new arraylist<namevaluepair>(2);             namevaluepairs.add(new basicnamevaluepair("request", "12345"));             httppost.setentity(new urlencodedformentity(namevaluepairs));              // execute http post request             httpresponse response = httpclient.execute(httppost);              // writing response log             httpentity resentity = response.getentity();              if (resentity != null) {                  string responsestr = entityutils.tostring(resentity).trim();                 log.v(tag, "response: " +  responsestr);                  string[] parts = responsestr.split(":");                 parts[1] = parts[1].replace("\"", "");                 parts[1] = parts[1].replace("}", "");                  if (parts[1].equals("01")){                     actionbar.setbackgrounddrawable(new colordrawable(color.parsecolor("#ffffff")));                 } else {                     log.v(tag, "no success: " + parts[1]);                 }              }          } catch (clientprotocolexception e) {             // todo auto-generated catch block         } catch (ioexception e) {             // todo auto-generated catch block         }          return null;     }      @override     protected void onpostexecute(void result) {         // todo auto-generated method stub         super.onpostexecute(result);         //runs in ui thread can update layout here     } } 

however, crashes app. guess i'll need change actionbar's color in onpagefinished method. however, don't know how variable asynctask onpagefinished. furthermore, don't know how change color color @color/ xml file...

try this,

    public class sendrequestasynctask extends asynctask <void, string, string> {  @override protected void onpreexecute() {     // todo auto-generated method stub     super.onpreexecute();     //runs in ui thread }  @override protected string doinbackground(void... params) {     // todo auto-generated method stub     string strreturn = "";      httpclient httpclient = new defaulthttpclient();     httppost httppost = new httppost("myscript.php");      try {         // add data         list<namevaluepair> namevaluepairs = new arraylist<namevaluepair>(2);         namevaluepairs.add(new basicnamevaluepair("request", "12345"));         httppost.setentity(new urlencodedformentity(namevaluepairs));          // execute http post request         httpresponse response = httpclient.execute(httppost);          // writing response log         httpentity resentity = response.getentity();          if (resentity != null) {              string responsestr = entityutils.tostring(resentity).trim();             log.v(tag, "response: " +  responsestr);              string[] parts = responsestr.split(":");             parts[1] = parts[1].replace("\"", "");             parts[1] = parts[1].replace("}", "");              strreturn = parts[1];         }      } catch (clientprotocolexception e) {         // todo auto-generated catch block     } catch (ioexception e) {         // todo auto-generated catch block     }      return strreturn; }  @override protected void onpostexecute(string result) {     // todo auto-generated method stub     super.onpostexecute(result);     //runs in ui thread can update layout here      if (result.equals("01")){         actionbar.setbackgrounddrawable(new colordrawable(color.parsecolor("#ffffff")));     } else {         log.v(tag, "no success: " + parts[1]);     } } }