FragmentDialog無法通過標籤將其添加到getSupportFragmentManager

任何你曾經遇到沒有被發現將其添加到片段Manager之後片段後立即發現了什麼？當我們試圖隱藏它時，它會停留在屏幕上。FragmentDialog無法通過標籤將其添加到getSupportFragmentManager

從片段：onActivityCreated我們顯示對話框：

@Override 
public void onActivityCreated(Bundle savedInstanceState) 
{ 
    super.onActivityCreated(savedInstanceState); 

    // Push the progress dialog 
    String text = getActivity().getString(R.string.httpLoadingData); 
    ((BaseFragmentActivity) getActivity()).showHttpWaitingDialog(text); 

    ... 
}

來自同一個片段之後一個新的線程裏面我們隱藏對話框：

private void prepareInitialWebViewData() { 
    initialFragmentWebDataLoadingThread = new Thread(new Runnable() { 

     @Override 
     public void run() { 
      updateDataAndView(); 

      BaseFragmentActivity activity = (BaseFragmentActivity) getActivity(); 

        BaseFragmentActivity activity = (BaseFragmentActivity) getActivity(); 
        if (activity != null) 
        { 
         activity.hideHttpWaitingDialog(); 
        } 

      // We don't need to keep this handle any longer since we've done 
      // the work 
      initialFragmentWebDataLoadingThread = null; 
     } 
    }); 

    initialFragmentWebDataLoadingThread.start(); 
}

這裏是我們的BaseFragmentActivity發現代碼既顯示又隱藏。請注意，可以多次調用showdialog，所以我們保留一個refcount。

首先展示功能：

public void showHttpWaitingDialog(CharSequence title) 
{ 
    synchronized (mRefCount) 
    { 
     mRefCount++; 

     Log.w("showhideHttpWaitingDialog", "++mRefCount:" + mRefCount + ", Title:" + title); 

     FragmentManager fm = getSupportFragmentManager(); 
     if (fm != null) 
     { 
      Fragment frag = fm.findFragmentByTag("httpWaitDialog"); 

      if (frag == null) 
      { 
       WaitingOnHttpFragmentDialog dialog = WaitingOnHttpFragmentDialog.newInstance(title); 

       fm.beginTransaction().add(dialog, "httpWaitDialog").commit(); 
      } 
     } 
     else 
      Log.w("showhideHttpWaitingDialog", "fragman == null"); 
    } 
}

然後隱藏功能：

public void hideHttpWaitingDialog() 
{ 
    synchronized (mRefCount) 
    { 
     Log.w("showhideHttpWaitingDialog", "--mRefCount:" + mRefCount); 

     if (mRefCount < 0) 
     { 
      Log.w("showhideHttpWaitingDialog", "Why are you trying to hide something that doesn't exists?"); 
      mRefCount = 0; 
     } 
     else 
     { 
      if (mRefCount == 0) 
      { 
       FragmentManager fragman = getSupportFragmentManager(); 
       if (fragman != null) 
       { 
        Fragment frag = fragman.findFragmentByTag("httpWaitDialog"); 

        if (frag != null) 
        { 
         fragman.beginTransaction().remove(frag).commit(); 
         Log.w("showhideHttpWaitingDialog", "dismissed normally"); 
        } 
        else 
         Log.w("showhideHttpWaitingDialog", "httpWaitDialog not found!"); 
       } 
      } 
     } 
    } 
}

來源

2012-05-03 Richard Lalancette