android - 在从 AsyncTaskLoader 完成 onLoadFinished 后动态更新 Fragment 的 UI - 无法获取 ViewGroup

Question

以前，我有一个 Fragment，它根据耗时的获取数据更新其 UI。

public class HomeMenuFragment extends SherlockFragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        Infos arg1 = performTimeConsumingDataStructureLoading();

        // Add in various UI views in v, according to information in loaded
        // data structure.
        View v = inflater.inflate(R.layout.home_menu, container, false);
        // ...
        // Adding several LinearLayout and TextView into v, based on
        // information from loaded data structure (arg1)
        // ...
        return v;
    }
    ....
}

这真的不是一个好的设计。有时，performTimeConsumingDataStructureLoading 可能需要超过 5 秒，我会收到 ANR(应用程序无响应)

引用http://developer.android.com/reference/android/content/AsyncTaskLoader.html ，我最终得到了更好的解决方案。我遇到的示例是，它通过 ArrayAdapter 间接更新其 UI。

public class HomeMenuFragment extends SherlockFragment implements LoaderManager.LoaderCallbacks<HomeMenuFragment.Infos> {
    @Override
    public void onLoadFinished(Loader<Infos> arg0, Infos arg1) {
        LayoutInflater inflater = this.getLayoutInflater(null);
        ViewGroup container = (ViewGroup)this.getView().getParent();
        // Remove previous old views, as onLoadFinished might be triggered
        // by onContentChanged too.
        container.removeAllViews();

        View v = inflater.inflate(R.layout.home_menu, container, false);
        // ...
        // Adding several LinearLayout and TextView into v, based on
        // information from loaded data structure (arg1)
        // ...
        container.addView(v);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        return super.onCreateView(inflater, container, savedInstanceState);
    }     
    ....
}

我没有 ArrayAdapter，因为我没有使用 ListFragment。我想要做的是将几个 TextView 添加到几个 LinearLayout 中。然后，我会将 LinearLayout 添加到 Fragment 的容器中。

但是，下面的代码给我空指针异常。

ViewGroup container = (ViewGroup)this.getView().getParent();

据我所知，在 AsyncTaskLoader 的 onLoadFinished 之后动态更新 Fragment UI 的正确方法是什么？

Answer 1

However, most example I encounter is, they update their UI indirectly through an ArrayAdapter.

使用 Loader 并不要求您必须使用 ListView，您可以更新应用程序中的任何目标 View 。

What I know what is the correct way to update Fragment UI dynamically, after onLoadFinished from AsyncTaskLoader?

从 Fragment 的 View 中获取对容器的引用，您将在其中放置额外的 View 并添加新 View 。

@Override
public void onLoadFinished(Loader<Infos> arg0, Infos arg1) {      
    // for some reason the fragment's view isn't built yet so abort things 
    if (getView() == null) {
         ViewGroup container = (ViewGroup) getView().findViewById(R.id.containerId);
         ViewGroup container = getViewcontainer.removeAllViews();
         // ...
         // Adding several LinearLayout and TextView into v, based on
         // information from loaded data structure (arg1)
         // ...
         container.addView(v);
    }
}

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