为什么ProgressDailog不显示？

问题描述：

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(); 
    } 
    };

为什么progressdialog没有显示？哪里是显示它的正确位置？

答

progressDialog.show（）只能从UI线程执行。只是做到以下几点：代替：

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

使用此代码：

a.runOnUiThread(new Runnable() { 

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

      } 
     });

同样的事情与解雇（）方法

它的工作原理。非常感谢。 – Santhosh 2012-03-19 06:20:11

欢迎您。总是乐于提供帮助 – 2012-03-19 17:36:58

答

你应该使用AsyncTask而不是使用线程。 UI只能从UI线程处理。您无法从其他线程处理UI线程。

有关此请阅读我的博客的详细信息在下面的链接

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

为什么ProgressDailog不显示？

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