安卓ProgressDialog，線程第一次不顯示

Question

嗨我的ListView上我的線程有一些問題。當我第一次運行線程不工作，但如果我回去再次運行該活動，每件事情都可以正常工作。

那是我的代碼：

protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     getListView().setOnItemClickListener(listlistener); 
     // Find the ListView resource. 
     raid_list = new ArrayList<RaidWpis>(); 
     this.m_adapter = new OrderAdapter(this, R.layout.row, raid_list); 
     setListAdapter(this.m_adapter); 

     viewOrders = new Runnable(){ 
      @Override 
      public void run() { 
       getOrders(); 
      } 
     }; 
     Thread thread = new Thread(null, viewOrders, "raid"); 
     thread.start(); 
     m_ProgressDialog = ProgressDialog.show(Raidy_lista.this,"Prosze czekac...", "Pobieram dane ...", true); 


     //ładowanie raidów z serwera 
     tv = (TextView)findViewById(R.id.tresc_gry); 
     text = "brak odpowiedzi"; 
     tv.setText("wysyłam plik"); 

     /* 
     try { 
      postData(); 
     } catch (JSONException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     */ 

    } 

private void getOrders() { 

     tv = (TextView)findViewById(R.id.tresc_gry); 
      try{ 
       raid_list = new ArrayList<RaidWpis>(); 

       // Create a new HttpClient and Post Header 

       SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this); 
       if (sharedPrefs.getString("ustawienia_wybrana_gra","1").equals("1")) 
       { 
        user_login=sharedPrefs.getString("ustawienia_gra_1_login","1"); 
        user_haslo=sharedPrefs.getString("ustawienia_gra_1_haslo","1"); 
        user_adres=getString(R.string.ustawienia_gra_1_adres); 
       } 
       else 
       { 
        user_login=sharedPrefs.getString("ustawienia_gra_2_login","1"); 
        user_haslo=sharedPrefs.getString("ustawienia_gra_2_haslo","1"); 
        user_adres=getString(R.string.ustawienia_gra_2_adres); 
       } 
       HttpClient httpclient = new DefaultHttpClient(); 
       HttpPost httppost = new HttpPost(user_adres+"/raidplanner_android.php"); 
       JSONObject json = new JSONObject(); 
       //tv.append("\nŁącza z serwerem"); 
       try { 
        // JSON data: 
        tv.append("\nWysyłam dane"); 
        tv.append("\nStrona:" + user_adres); 
        tv.append("\nLogin:" + user_login); 
        tv.append("\nHasło:" + user_haslo); 
        json.put("metoda", "pokaz_raidplanner"); 
        json.put("login", user_login); 
        json.put("haslo", user_haslo); 
        json.put("strona", user_adres); 

        JSONArray postjson=new JSONArray(); 
        postjson.put(json); 

        // Post the data: 
        httppost.setHeader("json",json.toString()); 
        httppost.getParams().setParameter("jsonpost",postjson); 

        // Execute HTTP Post Request 
        //System.out.print(json); 
        //httppost.setEntity(new UrlEncodedFormEntity(json)); 
        HttpResponse response = httpclient.execute(httppost); 
        tv.append("\nOdbieram dane"); 
        // for JSON: 
        if(response != null) 
        { 
         tv.append("\nDane odebrane\n\n"); 
         InputStream is = response.getEntity().getContent(); 

         BufferedReader reader = new BufferedReader(new InputStreamReader(is)); 
         StringBuilder sb = new StringBuilder(); 

         String line = null; 
         try { 
          while ((line = reader.readLine()) != null) { 
           sb.append(line + "\n"); 
          } 
         } catch (IOException e) { 
          e.printStackTrace(); 
          tv.append("\nBłąd IO"); 
         } finally { 
          try { 
           is.close(); 
          } catch (IOException e) { 
           e.printStackTrace(); 
          } 
         } 
         text = sb.toString(); 
        } 
        //tv.append(text); 
        JSONObject entireJson = new JSONObject(text); 
        //String odpowiedz = entireJson.getString("odpowiedz"); 
        JSONObject raidyObject = entireJson.getJSONObject("raidy"); 
        JSONArray raidyIds= raidyObject.getJSONArray("id"); 
        JSONArray raidyNazwy= raidyObject.getJSONArray("nazwa"); 
        //tv.append("\nArray zrobiony"); 


        for (int i = 0; i < raidyNazwy.length(); i++) 
        { 

         raid_list.add(new RaidWpis(raidyIds.getString(i), raidyNazwy.getString(i))); 
         //listAdapter.add(raidyNazwy.getString(i)); 
        } 
        //tv.append("\n"+odpowiedz); 
       } 
       catch (ClientProtocolException e) 
       { 
        // TODO Auto-generated catch block 
        tv.append("\nBłąd protocol"); 
       } 
       catch (IOException e) 
       { 
        // TODO Auto-generated catch block 
        tv.append("\nBłąd IO 2"); 
       } 

       // RaidWpis o1 = new RaidWpis("1","aaa"); 
       // o1.setOrderName("SF services"); 
       // o1.setOrderStatus("Pending"); 
       // RaidWpis o2 = new RaidWpis("2","bbb"); 
        //o2.setOrderName("SF Advertisement"); 
        //o2.setOrderStatus("Completed"); 
       // raid_list.add(o1); 
       // raid_list.add(o2); 
        Thread.sleep(4000); 
       // Toast.makeText(getBaseContext(), "dziala", Toast.LENGTH_LONG).show(); 
       } catch (Exception e) { 
        //Toast.makeText(getBaseContext(), "błąd", Toast.LENGTH_LONG).show(); 
        Log.d("BACKGROUND_PROC", e.getMessage()); 
       } 
       runOnUiThread(returnRes); 
      } 

我注意到，Log.d("BACKGROUND_PROC", e.getMessage());在logcat中顯示

01-16 18:51:17.703: D/BACKGROUND_PROC(4175): Only the original thread that created a view hierarchy can touch its views. 

Answer 1

此錯誤的主要原因是

您試圖訪問UI components（查看）從Thread方法中的背景線程。你不能這樣做。 not allowed to do that。

編輯：

你必須移動，更新用戶界面到主線程後臺任務的一部分。有一段簡單的代碼如下：

runOnUiThread(new Runnable() { 
    public void run() { 

//stuff that updates ui 

    } 
}); 

就窩這是在後臺運行的方法裏面，然後複製粘貼實現在塊的中間的任何更新的代碼。