Android ListView沒有刷新馬上使用notifyDataSetChanged

Question

我正在建立一個用戶界面，我在其中使用ListView來保存用戶提出的問題的數據。每當用戶創建新問題時，我都會嘗試更新列表視圖。現在的問題是數據更新但不是馬上。添加問題後，我需要導航到另一個屏幕，然後回來查看更新的列表。這也造成我想解決一些其他問題（佈局沒有得到正確顯示） 這是我的活動代碼：

public class QuestionsScreen extends Activity { 

..... 
..... 
..... 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_questions_screen); 

     ..... 

     questions=new ArrayList<String>(); 
     qId=new ArrayList<Integer>(); 

     ..... 
     ..... 

     //building API 
     resourceApi = ApiBuilder.getResourceApi(token); 

     // calling API function to get questions from db 

     resourceApi.listQuestions(groupId, new Callback<List<Question>>(){ 

      @Override 
      public void failure(RetrofitError arg0) { 
       // TODO Auto-generated method stub 

      } 

      @Override 
      public void success(List<Question> arg0, Response arg1) { 
       // TODO Auto-generated method stub 
       for(Question q:arg0) 
       { 
        questions.add(q.getTitle()); 
        qId.add(q.getId()); 

       } 

      } 

     }); 


     adapter= new ArrayAdapter<String>this,android.R.layout.simple_list_item_1,questions); 
     lv.setAdapter(adapter); 

     ..... 

     AlertDialog.Builder dialog = new AlertDialog.Builder(this); 
     LayoutInflater inflater = getLayoutInflater(); 
     final View x; 
     x = inflater.inflate(R.layout.groupdialog, null); 
     dialog.setView(x); 
     dialog.setTitle("Add question"); 
     TextView t= (TextView)x.findViewById(R.id.dialogTv); 
     t.setText("Please type in the question"); 

     dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() { 

      @Override 
      public void onClick(DialogInterface d, int which) { 
       // TODO Auto-generated method stub 
       name = (EditText) x.findViewById(R.id.dialog_groupName); 
       out = name.getText().toString(); 
       addQuestion(); 
       d.dismiss(); 
      } 
     }); 

     dialog.setNegativeButton("Cancel", 
       new DialogInterface.OnClickListener() { 

        @Override 
        public void onClick(DialogInterface d, int which) { 
         // TODO Auto-generated method stub 
         d.cancel(); 
        } 
       }); 

     alert = dialog.create(); 

     //button to ask a new question 
     newQ.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       alert.show(); 
      } 
     }); 

    } 

這是被稱爲當「添加新問題」功能按鈕被按下：

public void addQuestion() 
    { 
     resourceApi.createQuestion(groupId, out, new Callback<Question>(){ 

      @Override 
      public void failure(RetrofitError err) { 
       // TODO Auto-generated method stub 

      } 

      @Override 
      public void success(Question q, Response response) { 
       // TODO Auto-generated method stub 
//    adapter.add(q.getTitle()); 
       questions.add(q.getTitle()); 
       qId.add(q.getId()); 
      } 

     }); 

     adapter.notifyDataSetChanged(); 
     Toast.makeText(QuestionsScreen.this, "New Question created",Toast.LENGTH_LONG).show(); 
    } 

顯示吐司。但是，列表視圖不會隨新問題而更新。我嘗試使用adapter.add（）以及它只是導致一些其他問題，所以我不想使用它。 任何人都可以提出一個更好的方法或指出我做錯了什麼？

Answer 1

你必須通知你的數據在回調（成功函數）

嘗試是這樣的：

resourceApi.createQuestion(groupId, out, new Callback<Question>(){ 

     @Override 
     public void failure(RetrofitError err) { 
      // TODO Auto-generated method stub 

     } 

     @Override 
     public void success(Question q, Response response) { 
      // TODO Auto-generated method stub 
      adapter.add(q.getTitle()); 
      questions.add(q.getTitle()); 
      qId.add(q.getId()); 
//Notify once you have add something in questions 
      adapter.notifyDataSetChanged(); 
     } 

});