多个ListFragments的片段管理最佳实践

Question

我计划在一个活动中包含3个片段列表。目标是从第一个列表中选择"talk"选项，然后根据你在"talk"列表中点击的内容转到"run"列表，最后在"run"列表中，根据你点击的内容转到最终的"eat"列表。这应该在片段本身中发生（就像我所描述的那样），还是调用活动来处理来回传递数据？

public class OptionsActivity extends Activity {

    protected TalkFragment talk;
    protected RunFragment run;
    protected EatFragment eat;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        talk = new TalkFragment();
        run = new RunFragment();
        eat = new EatFragment();
    } 
}


public class TalkFragment extends ListFragment {
    private Cursor mCursor;
    int mCurCheckPosition = 0;

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

    }
    @Override
    public void onListItemClick(ListView l, View v, int pos, long id) {
        mCurCheckPosition = pos;
        // We can display everything in-place with fragments.
        // Have the list highlight this item and show the data.
        getListView().setItemChecked(pos, true);

        // Check what fragment is shown, replace if needed.
        RunFragment run_frag = (RunFragment) getFragmentManager().findFragmentById(R.id.fragment_run);
        if (run_frag == null || run_frag.getShownIndex() != pos) {
            run_frag = RunFragment.newInstance(pos);
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.replace(R.id.details, details);
            ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
            ft.commit();
        }

    } 
}

这显然只是一些片段，但你有了思路。如果我这样做，我不确定如何正确地传递某些参数到片段中。理想情况下，RunFragment应该根据TalkFragment中所点击的项目的ID来知道要显示什么。这些参数是否需要通过Activity传递？

- Du3

Answer 1

我通常的做法是让Activity作为处理Fragment的交通警察。您的onListItemClick实现只需告诉Activity它想要做什么：

public class OptionsActivity extends Activity {

    protected TalkFragment talk;
    protected RunFragment run;
    protected EatFragment eat;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        talk = new TalkFragment();
        run = new RunFragment();
        eat = new EatFragment();
    }

    public void showRunFragment() {
        showFragment(R.id.fragment_run);
    }

    public void showEatFragment() {
        showFragment(R.id.fragment_eat);
    }

    public void showFragment(int fragmentId) {
        // Check what fragment is shown, replace if needed.

        ...
    }
}


public class TalkFragment extends ListFragment {
    private Cursor mCursor;
    int mCurCheckPosition = 0;

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

    }

    @Override
    public void onListItemClick(ListView l, View v, int pos, long id) {
        mCurCheckPosition = pos;
        // We can display everything in-place with fragments.
        // Have the list highlight this item and show the data.
        getListView().setItemChecked(pos, true);

        getActivity().showRunFragment()
    } 
} 

- Kelly Merrell