Question

我正在构建一个ListFragment。在肖像中它需要两个标题，但在横向上我需要左侧的这些标题和右侧的ListView。 xml处理不同的布局，java处理正确填充/更新它们。

除了在方向更改时，标题不会保留在列表中。 listView甚至可以保留滚动，但是通过删除标题来移动。

嵌套片段可能更好，但listview不会保持framelayout，因此这是一个有争议的点。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setRetainInstance(true);

    loadFeeds();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.fragment_profile, container, false);

    return v;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    setupList(savedInstanceState);
    setupOrienation();

    super.onActivityCreated(savedInstanceState);
}

private void setupList(Bundle savedInstanceState) {
    if(getListAdapter() == null) {
        listProfileButtons = (View)getLayoutInflater(savedInstanceState).inflate(R.layout.view_profile_buttons, null);
        listProfile = (View)getLayoutInflater(savedInstanceState).inflate(R.layout.view_profile_header, null);

        getListView().addHeaderView(listProfile);
        getListView().addHeaderView(listProfileButtons);
    } 
}

private void setupOrienation(){
    if(getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
        listProfile.setVisibility(View.GONE);
        listProfileButtons.setVisibility(View.GONE);
        setupProfile(getView());
        setupButtons(getView());
        getListView().setOnScrollListener(new OnScrollListener() {

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            }
        });
    } else {
        listProfile.setVisibility(View.VISIBLE);
        listProfileButtons.setVisibility(View.VISIBLE);
        //setupProfile(getListView());
        //setupButtons(getListView());
        setupButtons(getView().findViewById(R.id.include_profile_buttons));

        getListView().setOnScrollListener(new OnScrollListener() {

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if(firstVisibleItem > 0) {
                    getView().findViewById(R.id.include_profile_buttons).setVisibility(View.VISIBLE);
                } else {
                    getView().findViewById(R.id.include_profile_buttons).setVisibility(View.GONE);
                }

            }
        });

    }
}

private void setupProfile(View parent) {
    Bundle userBundle = getArguments();

    TextView name = (TextView)parent.findViewById(R.id.text_view_profile_name);
    TextView screenName = (TextView)parent.findViewById(R.id.text_view_profile_at_user);
    ImageView image = (ImageView)parent.findViewById(R.id.image_view_profile_picture);

    name.setText(userBundle.getString(User.USER_NAME));
    screenName.setText("@" + userBundle.get(User.SCREEN_NAME));
    ImageCacheManager.getInstance(getActivity()).bindDrawable(userBundle.getString(User.PROFILE_IMAGE), image);

}

private void setupButtons(View v) {
    Bundle userBundle = getArguments();

    Button buttonTweets = (Button)v.findViewById(R.id.button_number);
    Button buttonFollowing = (Button)v.findViewById(R.id.button_follow);
    Button buttonFollowers = (Button)v.findViewById(R.id.button_friends);

    buttonTweets.setText(getResources().getString(R.string.profile_number, userBundle.getInt(User.NUMBER)));
    buttonFollowing.setText(getResources().getString(R.string.profile_number_follow, userBundle.getInt(User.NUMBER_OF_FOLLOW)));
    buttonFollowers.setText(getResources().getString(R.string.profile_number_friends, userBundle.getInt(User.NUMBER_OF_FRIENDS)));

    buttonTweets.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            switchListAdapter(adapter);
        }
    });

    buttonFollowing.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            switchListAdapter(followAdapter);
        }
    });

    buttonFollowers.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            switchListAdapter(friendsAdapter);
        }
    });
}

完成注释代码，以便在标头丢失后停止空指针异常。

Answer 1

因此在轮换时，所有视图都会被销毁，这意味着标题。我相信当你setRatainInstance（true）时它应该处理ListFragment头中的头但不会。要使用带有使用retainInstance的ListFragment的Headers，您必须：

@Override
public void onDestroyView() {
    setListAdapter(null);
    super.onDestroyView();
}

然后我只在我需要的方向添加标题，这很好。关于它的负面部分是scroll isn't retained，我必须弄清楚应该使用哪个适配器。这些只是几种方法，虽然不是太糟糕。

方向更改后，标题不会保留在ListFragment中

1 个答案: