顯示進度對話框，直到將數據加載到列表

Question

我開發的應用程序中加載到ArrayList的數據需要2/3秒。我想要顯示將數據加載到ArrayList的進度。

我正在使用AsyncTask。我通過單擊按鈕執行此操作，當ArrayList完全加載時，它將通過Intent傳遞給下一個活動。是

showList.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(final View v) { 

     if (session.isOpened()) { 

     if (friendID.size() == 0 && friendName.size() == 0) { 

     new Async().execute(); 
     } 
    } 
}); 

Ansyc Task類如下 - - 巴頓

代碼片段如下 -

的onClick

class Async extends AsyncTask<String, Integer, String> { 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 

     dialog.setTitle("Loading..."); 
     dialog.setIcon(R.drawable.ic_launcher); 
     dialog.setMessage("Please wait for completion"); 
     dialog.setProgress(0); 

     dialog.show(); 
    } 

    @Override 
    protected String doInBackground(String... params) { 

     Request.executeMyFriendsRequestAsync(session, 
      new Request.GraphUserListCallback() { 

          @Override 
      public void onCompleted(List<GraphUser> users, 
          Response response) { 

       Iterator<GraphUser> iterator = users.iterator(); 
       GraphUser graphUser = null; 

        friendID.clear(); 
        friendName.clear(); 

        while (iterator.hasNext()) { 
          if (iterator != null) { 
           graphUser = iterator.next(); 

           Log.d("Friend Information ", 
             " friend ID " + graphUser.getId() 
               + " friend Name " 
               + graphUser.getName()); 

           friendID.add(graphUser.getId()); 
           friendName.add(graphUser.getName()); 

           publishProgress(friendID.size()); 

           Log.d("Friend Information ", " friendID= " 
             + friendID.size() + " friendName " 
             + friendName.size()); 
          } 
         } 
        } 

       }); 

     dialog.dismiss(); 
     return "sucess"; 
    } 

    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 

     Intent intent = new Intent(MainActivity.this, FriendsList.class); 

     Log.d("Checking the size ", "ID " + friendID.size() + " UserName " 
       + friendName.size()); 

     /* 
     * Toast.makeText(MainActivity.this, text, Toast.LENGTH_SHORT) 
     * .show(); 
     */ 

     intent.putStringArrayListExtra("userID", friendID); 
     intent.putStringArrayListExtra("userName", friendName); 
     intent.putExtra("str", result); 
     startActivity(intent); 
    } 

    @Override 
    protected void onProgressUpdate(Integer... values) { 
     dialog.setProgress(values[0]); 
     //dialog.incrementProgressBy(values[0]); 
     super.onProgressUpdate(values); 
    } 
} 

在登錄貓的錯誤 -

04-12 14:15:56.595: E/AndroidRuntime(15794): FATAL EXCEPTION: AsyncTask #2 
04-12 14:15:56.595: E/AndroidRuntime(15794): **java.lang.RuntimeException: An error occured while executing doInBackground()** 

04-12 14:15:56.595: E/AndroidRuntime(15794): at android.os.AsyncTask$3.done(AsyncTask.java:200) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.FutureTask.setException(FutureTask.java:125) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.FutureTask.run(FutureTask.java:138) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 

04-12 14:15:56.595: E/AndroidRuntime(15794): at java.lang.Thread.run(Thread.java:1019) 
04-12 14:15:56.595: E/AndroidRuntime(15794): **Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()** 

Answer 1

2分：

1. 看起來你Request.executeMyFriendsRequestAsync是一個異步操作，所以你只是要求一些動作，並從AsyncTask.doInBackground()迅速返回。因此，通過這樣的設計，數據加載本身稍後會發生，當AsyncTask.doInBackground()已經通過。您需要打開一個sycn API，以便在AsyncTask.doInBackground()中加載所有好友數據。

2. 呼叫dialog.dismiss();內的AsyncTask.onPostExecute()