Code work slow in blackberry device

I have code that work fine but unexpectedly work slow in blackberry device

public ContactsScreen()//(Object _app)
    {

     setTitle(new LabelField( "Contac开发者_Python百科ts",LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH));     


       //_contactNamesVector = new Vector();
    _contactVector = new Vector();
    _contacts = getContactListInVector();
       //ReadableList _readableList =(ReadableList) _contacts;
    if(_contacts != null)
    {
     // Create an instance of our SortedReadableList class. 
   //it takes _contacts as vector and then sort it accordingly

     _contactSortedList = new ContactSortedList(_contacts);        

     // Add our list to a KeywordFilterField object.
     _keywordFilterField = new KeywordFilterField()
     {

      protected boolean navigationClick(int status,int time)
      {      
       int index = getSelectedIndex();

       //Return data in redableklist format ie collectionlist and boolean
       ContactInfo data = (ContactInfo)getSelectedElement();
       data.toggleChecked();
       invalidate(index);
       if(data.isChecked())
       {
         // UiApplication.getUiApplication().popScreen(getScreen());
          data.displayMultipleContacts();

        //String str1 = data.getCompanyName();
        //Dialog.alert(str1);
        //String str2 = data.getFirstName();
        //Dialog.alert(str2);
        //String str3 = data.getLastName();
        //Dialog.alert(str3);
        //String str4 = str1.concat(str2).concat(str3);

       }
       return true;
      }
//       public boolean keyChar(char key, int status, int time){
//        if(key == Keypad.KEY_ENTER){
//        int index = getSelectedIndex();
//          //Return data in redableklist format ie collectionlist and boolean
//          ContactInfo data = (ContactInfo)getSelectedElement();
//          data.toggleChecked();
//          invalidate(index);
//          if(data.isChecked())
//          {
//            // UiApplication.getUiApplication().popScreen(getScreen());
//             data.displayMultipleContacts();
//           
//           //String str1 = data.getCompanyName();
//           //Dialog.alert(str1);
//           //String str2 = data.getFirstName();
//           //Dialog.alert(str2);
//           //String str3 = data.getLastName();
//           //Dialog.alert(str3);
//           //String str4 = str1.concat(str2).concat(str3);
//           
//          }
//         
//        }
//        if(key == Keypad.KEY_ESCAPE){
//         UiApplication.getUiApplication().popScreen(getScreen());
//         
//        }
//        return true;
//       }

     };
     _keywordFilterField.setSourceList(_contactSortedList,_contactSortedList);      

   //register keywordfield with Callbackinterface list display, it call methods of callback 
     _keywordFilterField.setCallback(_contactSortedList);


     _contactSortedList.setReadableList(_keywordFilterField.getResultList());

     // We're providing a customized edit field for
     // the KeywordFilterField.
     CustomKeywordField customSearchField = new CustomKeywordField();
     _keywordFilterField.setKeywordField(customSearchField);        



     // We need to explicitly add the search/title field via MainScreen.setTitle().
     this.setTitle(_keywordFilterField.getKeywordField());            

     // Add our KeywordFilterField to the screen and push the screen
     // onto the stack.
     this.add(_keywordFilterField);
    }

    }