在哪裏發射片段活動中的異步腳本

Question

我有一個片段活動並希望從我的php腳本中獲取數據。我需要這些數據來有效地繪製我的UI。我的問題是我的UI /碎片在我得到數據之前畫出來，我不知道爲什麼，因爲我儘早在onCreate中啓動它。我把一個對話框放入前後，以有效地凍結用戶界面，同時數據在後臺被回收，但是......我沒有看到這種情況發生，我認爲在調試過程中出現對話時調用它太晚了，它顯示了繪製屏幕的頂部這讓我感到莫名其妙。

我有一個替代的解決方案是在調用活動（之前的活動）中激發asyncTask並將結果傳入包中，但我不喜歡此解決方案，因爲它的剛性和可能導致屏幕旋轉的問題。

我一直堅持這個很長時間，任何人都可以告訴我在哪裏把我的異步執行 - 對話框應該有效地使其同步過程。我把我的異想天開地放在我認爲可能/理智和沒有運氣的地方。

在下面我執行oncreate()。注意執行不會更新任何內容，而是預先更新一個「不變」的測試字符串，並在後綴中更改「已更改」，以便我可以在代碼中的各個點上看到它的狀態。它不會改變，然後我畫我的屏幕。

public class StaggeredGridActivityFragment extends FragmentActivity { 


    String test ="not changed"; 
    private TilesAdapter mAdapter; 
    private ArrayList<String> mData; 
    private StaggeredGridView mGridView; 

    private static final String TAG = "StaggeredGridActivityFragment"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     try 
     { 
      // Loading tile data in Background Thread 
      new GetLoginTiles().execute(); 
     } 
     catch (Exception e) 
     { 
      e.printStackTrace(); 
     } 
     super.onCreate(savedInstanceState); 

     this.requestWindowFeature(Window.FEATURE_NO_TITLE); //remove title bar 

     final FragmentManager fm = getSupportFragmentManager(); 

     // Create the list fragment and add it as our sole content. 
     if (fm.findFragmentById(android.R.id.content) == null) { 
      final StaggeredGridFragment fragment = new StaggeredGridFragment(); 
      fm.beginTransaction().add(android.R.id.content, fragment).commit(); 
     } 
     Intent i=getIntent(); 
     Bundle extras = i.getExtras(); 
     String tmp = extras.getString("myKey"); 

    } 


    private class StaggeredGridFragment extends Fragment implements AbsListView.OnScrollListener, AbsListView.OnItemClickListener { 
       //private StaggeredGridView mGridView; 
       private boolean mHasRequestedMore; 
       // private TilesAdapter mAdapter; 

       //private ArrayList<String> mData; 

       @Override 
       public void onCreate(final Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setRetainInstance(true); 
       } 

       @Override 
       public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) { 
        return inflater.inflate(R.layout.activity_sgv, container, false); 
       } 

       @Override 
       public void onActivityCreated(final Bundle savedInstanceState) { 
        List<NameValuePair> params = new ArrayList<NameValuePair>(); 

        //Encapsulate all within a post cereate from a async task or call a blocking http call 
        super.onActivityCreated(savedInstanceState); 

        mGridView = (StaggeredGridView) getView().findViewById(R.id.grid_view); 

        if (savedInstanceState == null) { 
         final LayoutInflater layoutInflater = getActivity().getLayoutInflater(); 
         View header = layoutInflater.inflate(R.layout.list_item_header_footer, null); 
         mGridView.addHeaderView(header); 
        } 

        if (mAdapter == null) { 
         mAdapter = new TilesAdapter(getActivity(), R.id.summary1_value); 
        } 

        if (mData == null) { 
         mData = ActivityTileData.getLoginTileDataArray(getActivity()); 
        } 


        for (String data : mData) { 
         mAdapter.add(data); //Add each mData TileAdapter element to an mAdapter where it will be further broken down and used by the TileAdapter 
        } 

        mGridView.setAdapter(mAdapter); 
        mGridView.setOnScrollListener(this); 
        mGridView.setOnItemClickListener(this); 
       } 

       @SuppressLint("LongLogTag") 
       @Override 
       public void onScrollStateChanged(final AbsListView view, final int scrollState) { 
        Log.d(TAG, "onScrollStateChanged:" + scrollState); 
       } 

       @SuppressLint("LongLogTag") 
       @Override 
       public void onScroll(final AbsListView view, final int firstVisibleItem, final int visibleItemCount, final int totalItemCount) { 
        Log.d(TAG, "onScroll firstVisibleItem:" + firstVisibleItem + 
          " visibleItemCount:" + visibleItemCount + 
          " totalItemCount:" + totalItemCount); 
        // our handling 
        if (!mHasRequestedMore) { 
         int lastInScreen = firstVisibleItem + visibleItemCount; 
         if (lastInScreen >= totalItemCount) { 
          Log.d(TAG, "onScroll lastInScreen - so load more"); 
          mHasRequestedMore = true; 
          onLoadMoreItems(); 
         } 
        } 
       } 

       //Loads all of the objects from the getLoginTileData() if called 
       private void onLoadMoreItems() { 
        while(mAdapter.getCount()<mData.size()) { 
         //final ArrayList<String> sampleData = SampleData.generateSampleData(); 
         final ArrayList<String> loginTileData = ActivityTileData.getLoginTileDataArray(getActivity()); 
         for (String data : loginTileData) { 
          mAdapter.add(data.toString()); 
         } 
         // stash all the data in our backing store 
         mData.addAll(loginTileData); 
         // notify the adapter that we can update now 
         mAdapter.notifyDataSetChanged(); 
         mHasRequestedMore = false; 
        } 
       } 

       @Override 
       public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) { 
        Toast.makeText(getActivity(), "Item Clicked: " + position, Toast.LENGTH_SHORT).show(); 
       } 
      } 
    // Progress Dialog 
    private ProgressDialog qDialog; 
    // JSON parser class 
    JSONParser jParser = new JSONParser(); 
    String url_login ="http://xxx/xxx.php"; 
    /** 
    * Background Async Task to Load all images by making HTTP Request 
    * */ 
    class GetLoginTiles extends AsyncTask<String, String, String> { 
     /** 
     * Before starting background thread Show Progress Dialog 
     * */ 
     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 
      qDialog = new ProgressDialog(StaggeredGridActivityFragment.this); 
      qDialog.setMessage("Please wait..."); 
      qDialog.setIndeterminate(false); 
      qDialog.setCancelable(false); 
      qDialog.show(); 
     } 

     @Override 
     protected String doInBackground(String... args) { 
      // Building Parameters 
      List<NameValuePair> params = new ArrayList<NameValuePair>(); 
      // getting JSON string from URL 
      JSONObject jsonLogin = jParser.makeHttpRequest(url_login, "GET", params); 
      test=jsonLogin.toString(); 

      return jsonLogin.toString(); 
     } 

     /** 
     * After completing background task Dismiss the progress dialog 
     * **/ 
     protected void onPostExecute(String jsonString) { 
      // dismiss the dialog after getting all questions 
      qDialog.dismiss(); 
      // updating UI from Background Thread 
      runOnUiThread(new Runnable() { 
       public void run() { 
        /** 
        * Updating parsed JSON data into imagebuttons 
        * */ 
        test="local test has changed"; 
       } 
      }); 

     } 
    } 
} 

Answer 1

我有一個替代的解決方案這是火的AsyncTask呼籲活動（之前的活動），並通過導致包，但我不喜歡這樣的解決方案，它的剛性，並可能導致屏幕旋轉問題。

這是做

覆蓋的onSaveInstanceState保存旋轉

的演員也看到here更多細節

編輯一個好辦法：看來你是試圖改變文本使用

test =「本地測試已更改」;

whaat你需要做的是活動傳遞到的AsyncTask然後

VIEWTYPEHERE button= (VIEWTYPEHERE) activity.findViewById(R.id.YOUR_VIEW"S_ID_HERE); 

button.setText（ 「」）;

上後一對夫婦的音符

執行對UI線程運行時你並不需要一個新的可運行 你也忘了打電話給.RUN（）就可以了