安卓：难以启动的一个片段里的片段 [英] Android: Difficulty starting a fragment inside of a fragment

问题描述

所以，我previously问了一个问题，并得到了一些帮助，但最终，我决定，我需要更加清晰。

So, I previously asked a question, and got a bit of help, but ultimately, I decided that I needed to be more clear.

基本上，我有一个应用程序。主要活动是一个标签式的活动/刷卡视图。第一页包含Main_Fragment，它由其他两个片段（A和B）在其中的。片段A包含一个按钮，我想有当pressed，将推出不同的片段要么去ontop片段A和B，代替或Main_fragment。

Basically, I have an app. The Main activity is a tabbed activity/swipe view. The first page consists of Main_Fragment, which consists of two other fragments (A and B) within them. Fragment A contains a button, that I am trying to have when pressed, will launch a different fragment to either go ontop of fragment A and B, replace them or Main_fragment.

我在哪里卡住是code我需要使用的片段交易。 previously我用这个code，当Main_Fragment，只是一个活动，和它的工作很好，但我现在不能确定什么，我需要做的。

Where I am getting stuck is what code I would need to use for the Fragment Transaction. Previously I used this code, when Main_Fragment, was just an activity, and it worked out well, but now I am unsure on what I would need to do.

    FragmentManager fm = getFragmentManager();
    fragment = new DayViewFragment();

    FragmentTransaction ft = fm.beginTransaction();
    ft.addToBackStack(null);
    ft.add(android.R.id.content, fragment);
    ft.commit();

首先，我想我会需要使用getParentFragment（）不知何故，我不确定如何，其次我不能确定做替换什么android.R.id.content，尤其是，当code是内一个片段的片段的内侧。

Firstly I think I would need to use getParentFragment() somehow, and I am unsure on how, and secondly I am unsure what do replace for android.R.id.content, especially, when the code is inside a fragment inside of a fragment.

如果任何澄清是必要的，请询问。感谢您的帮助！

If any clarification is needed, please ask. Thanks for any help!

推荐答案

我想实现这种功能的最佳方法是使用一个接口回调从片段的活动。​​

I think the best way to implement this type of functionality is to use an interface callback from the Fragment to the Activity.

Android的工作室1.2.2甚至会自动创建界面回调code，如果你选中包含接口回调？复选框，创建一个新的片段时。

Android Studio 1.2.2 will even automatically create interface callback code if you check the "Include interface callbacks?" checkbox when creating a new Fragment.

下面是该片段一般code结构：

Here is the general code structure for the Fragment:

public class MainActivityFragment extends Fragment {

    private OnMainFragmentInteractionListener mListener;
    private Button exampleButton;

    public MainActivityFragment() {
    }

    public static MainActivityFragment newInstance() {
        MainActivityFragment fragment = new MainActivityFragment();
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_main, container, false);

        exampleButton = (Button) rootView.findViewById(R.id.button);

        exampleButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mListener.buttonClicked("test value");
            }
        });

        return rootView;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (OnMainFragmentInteractionListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement OnMainFragmentInteractionListener");
        }
    }

    public interface OnMainFragmentInteractionListener {
        void buttonClicked(String val);
    }
}

那么活动将实现接口：

Then the Activity will implement the interface:

public class MainActivity extends FragmentActivity
        implements MainActivityFragment.OnMainFragmentInteractionListener {

和实现接口的方法：

@Override
public void buttonClicked(String val) {

    FragmentManager fm = getFragmentManager();
    fragment = new DayViewFragment();

    FragmentTransaction ft = fm.beginTransaction();
    ft.addToBackStack(null);
    ft.add(android.R.id.content, fragment);
    ft.commit();

}

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