爲什麼ProgressDailog不顯示？

Question

這是我的代碼& probelm。

static Throwable t= null; 
static String responseFromServer = ""; 
static Activity a ; 
static Handler mHandler = new Handler(); 

public static String sendToServer(final Activity act, final String data) 
{  
     progDailog = ProgressDialog.show(act, "", " Please wait...", true); 
     progDailog.setCancelable(true); //BUT this not displaying 

     Thread th = new Thread() 
     { 
     public void run(){ 
       try{ 
        // .........code ... SENDING data to server 

       responseFromServer = httpclient.execute(httppost, new BasicResponseHandler()).trim(); 
       mHandler.post(showResponse); 
       } 
       catch (Exception e) 
       { 
        t = e; 
        e.printStackTrace(); 
        progDailog.dismiss(); 
        mHandler.post(exception); 
       } 
       } 
       }; 
      th.start(); 
      th.join(); 

    return responseFromServer; 
    } 

    private static Runnable showResponse = new Runnable() 
    { 
    public void run(){ 
     Toast.makeText(a, responseFromServer, Toast.LENGTH_SHORT).show(); 
     progDailog.dismiss(); 
    } 
    }; 

    private static Runnable exception = new Runnable() 
    { 
    public void run(){ 
     Toast.makeText(a, t + " ", Toast.LENGTH_SHORT).show(); 
     progDailog.dismiss(); 
    } 
    }; 

爲什麼progressdialog沒有顯示？ 哪裏是顯示它的正確位置？

Answer 1

progressDialog.show（）只能從UI線程執行。 只是做到以下幾點：代替 ：

progDailog = ProgressDialog.show(act, "", " Please wait...", true); 

使用此代碼：

a.runOnUiThread(new Runnable() { 

      @Override 
      public void run() { 
       progDailog = ProgressDialog.show(act, "", " Please wait...", true); 

      } 
     });  

同樣的事情與解僱（）方法

Answer 2

你應該使用AsyncTask而不是使用線程。 UI只能從UI線程處理。您無法從其他線程處理UI線程。

有關此請閱讀我的博客的詳細信息在下面的鏈接

http://pavandroid.blogspot.in/2010/09/how-to-create-calendar-in-android.html