Change Fragment layout on orientation change

问题:

I have the following problem:

I have a TabActivity that shows a FragmentActivity in one of its tabs.

That FragmentActivity adds a ListFragment, when clicked on the item of that ListFragment, a Fragment is added (also to the backstack) and displayed.

Now I need to change the layout of that Fragment to change when going to landscape orientation.

But I'm totally clueless where to implement that change. I have already created to correct layout in the layout-land folder. But where is the correct point to set it?

回答1:

Warning: this may be a pre-Lollipop answer.

A Fragment doesn't get re-inflated on configuration change, but you can achieve the effect as follows by creating it with a FrameLayout and (re)populating that manually:

public class MyFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle bundle) {
        FrameLayout frameLayout = new FrameLayout(getActivity());
        populateViewForOrientation(inflater, frameLayout);
        return frameLayout;
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        LayoutInflater inflater = LayoutInflater.from(getActivity());
        populateViewForOrientation(inflater, (ViewGroup) getView());
    }

    private void populateViewForOrientation(LayoutInflater inflater, ViewGroup viewGroup) {
        viewGroup.removeAllViewsInLayout();
        View subview = inflater.inflate(R.layout.my_fragment, viewGroup);

        // Find your buttons in subview, set up onclicks, set up callbacks to your parent fragment or activity here.
    }
}

I'm not particularly happy with the getActivity() and related calls here, but I don't think there's another way to get hold of those things.

Update: Removed cast of ViewGroup to FrameLayout and used LayoutInflater.from(), and the third parameter of inflate() instead of adding the view explicitly.

回答2:

I believe that if you have layouts that are for specific device orientations then all you need do is give them the same name but place them in the appropriate resource directory. This link gives some explanation. The Android system then takes care of selecting the appropriate resource but you can handle this yourself if needs be.