android - 如何在抽屉导航 fragment 中放置两个回收 View

Question

所以我在抽屉导航中的 fragment 上有一个 recyclerview，它工作正常。但是我想添加第二个 recyclerview 列出更多项目。这是可以实现的，但困难的部分是使整个布局一起滚动。

我用谷歌搜索了它，但没有发现任何有用的东西。我想你们中的一个人可能有解决办法。

这可能吗？

fragment 抽屉.java

public class FragmentDrawer extends Fragment {

    private static String TAG = FragmentDrawer.class.getSimpleName();

    private RecyclerView recyclerView;
    private ActionBarDrawerToggle mDrawerToggle;
    private DrawerLayout mDrawerLayout;
    private NavigationDrawerAdapter adapter;
    private View containerView;
    private static String[] titles = null;
    private FragmentDrawerListener drawerListener;

    public FragmentDrawer() {

    }

    public void setDrawerListener(FragmentDrawerListener listener) {
        this.drawerListener = listener;
    }

    public static List<NavDrawerItem> getData() {
        List<NavDrawerItem> data = new ArrayList<>();
        int[] icons = {R.drawable.home, R.drawable.ic_upcoming, R.drawable.ic_eventsaved, R.drawable.ic_wehappened, R.drawable.ic_persons};

        // preparing navigation drawer items
        for (int i = 0; i < titles.length && i < icons.length; i++) {
            NavDrawerItem navItem = new NavDrawerItem();
            navItem.setTitle(titles[i]);
            navItem.setIcon(icons[i]);
            data.add(navItem);
        }
        return data;
    }

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

        // drawer labels
        titles = getActivity().getResources().getStringArray(R.array.nav_drawer_labels);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflating view layout
        View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
        recyclerView = (RecyclerView) layout.findViewById(R.id.drawerList);

        adapter = new NavigationDrawerAdapter(getActivity(), getData());
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerView, new ClickListener() {
            @Override
            public void onClick(View view, int position) {
                drawerListener.onDrawerItemSelected(view, position);
                mDrawerLayout.closeDrawer(containerView);
            }

            @Override
            public void onLongClick(View view, int position) {

            }
        }));

        return layout;
    }


    public void setUp(int fragmentId, DrawerLayout drawerLayout, final Toolbar toolbar) {
        containerView = getActivity().findViewById(fragmentId);
        mDrawerLayout = drawerLayout;
        mDrawerToggle = new ActionBarDrawerToggle(getActivity(), drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close) {
            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                getActivity().invalidateOptionsMenu();
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
                getActivity().invalidateOptionsMenu();
            }

            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerSlide(drawerView, slideOffset);
                toolbar.setAlpha(1 - slideOffset / 2);
            }
        };

        mDrawerLayout.setDrawerListener(mDrawerToggle);
        mDrawerLayout.post(new Runnable() {
            @Override
            public void run() {
                mDrawerToggle.syncState();
            }
        });

    }

    public static interface ClickListener {
        public void onClick(View view, int position);

        public void onLongClick(View view, int position);
    }

    static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {

        private GestureDetector gestureDetector;
        private ClickListener clickListener;

        public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final ClickListener clickListener) {
            this.clickListener = clickListener;
            gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
                @Override
                public boolean onSingleTapUp(MotionEvent e) {
                    return true;
                }

                @Override
                public void onLongPress(MotionEvent e) {
                    View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
                    if (child != null && clickListener != null) {
                        clickListener.onLongClick(child, recyclerView.getChildPosition(child));
                    }
                }
            });
        }

        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {

            View child = rv.findChildViewUnder(e.getX(), e.getY());
            if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
                clickListener.onClick(child, rv.getChildPosition(child));
            }
            return false;
        }

        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e) {
        }

        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

        }


    }

    public interface FragmentDrawerListener {
        public void onDrawerItemSelected(View view, int position);
    }

NavigationDrawerAdapter.java

public class NavigationDrawerAdapter extends RecyclerView.Adapter<NavigationDrawerAdapter.MyViewHolder> {
    List<NavDrawerItem> data = Collections.emptyList();
    private LayoutInflater inflater;
    private Context context;

    public NavigationDrawerAdapter(Context context, List<NavDrawerItem> data) {
        this.context = context;
        inflater = LayoutInflater.from(context);

        this.data = data;
    }

    public void delete(int position) {
        data.remove(position);
        notifyItemRemoved(position);
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.nav_drawer_row, parent, false);
        MyViewHolder holder = new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        NavDrawerItem current = data.get(position);
        holder.title.setText(current.getTitle());
        holder.imgViewIcon.setImageResource(current.getIcon());
    }

    @Override
    public int getItemCount() {
        return data.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder {
        TextView title;
        public ImageView imgViewIcon;

        public MyViewHolder(View itemView) {
            super(itemView);
            title = (TextView) itemView.findViewById(R.id.title);
            imgViewIcon = (ImageView) itemView.findViewById(R.id.item_icon);
        }
    }
}

字符串.xml

<resources>

    <string name="nav_item_home">Home</string>
    <string name="nav_item_friends">Upcoming</string>
    <string name="nav_item_notifications">Saved</string>
    <string name="nav_item_main">weHappened</string>
    <string name="nav_item_planners">Event planners</string>

    <!-- navigation drawer item labels  -->
    <string-array name="nav_drawer_labels">
        <item>@string/nav_item_home</item>
        <item>@string/nav_item_friends</item>
        <item>@string/nav_item_notifications</item>
        <item>@string/nav_item_main</item>
        <item>@string/nav_item_planners</item>
    </string-array>

    <string name="title_messages">Events saved</string>
    <string name="title_friends">Upcoming events</string>
    <string name="title_home">Home</string>
    <string name="title_happened">Events weHappened</string>
    <string name="title_planners">Event planners</string>

</resources>

Answer 1

如果您想在同一列表中列出更多项目，请使用单个 RecyclerView。使用 2 个不同的 RecyclerView 是没有意义的，如果一个在另一个下面，则不能让它们一起滚动。

如果您想动态地向列表中添加更多项目，请在您的适配器中构建一个“更新”方法，并在您想要添加更多项目时调用该方法并调用 notifyItemRangeChanged()(或给定最合适的方法) RecyclerView.Adapter 类)

编辑:

假设您有一个 RecyclerView 集并且您知道如何使用基本的 LinearLayoutManager 初始化和设置它，我想只关注适配器。

因此，如果您想将“主要选项”和“其他选项”等 2 个类别分开，您可能需要考虑为 2 种 View 类型实现适配器。这是一个关于如何实现这一点的简短代码 fragment ，但这只强调了如何使用多种 View 类型的想法。您可能希望根据需要修改它:

public class DrawerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private static final int VIEW_TYPE_HEADER = 0;
    private static final int VIEW_TYPE_REGULAR_ITEM = 1;

    private LayoutInflater mInflater;
    private List<Object> mItems;

    public DrawerAdapter(Context context) {
        mInflater = LayoutInflater.from(context);
        mItems = new ArrayList<>();
        mItems.add("Main options");
        mItems.add(new Item("Option1", R.drawable.icons_for_option_1))
        mItems.add(new Item("Option2", R.drawable.icons_for_option_2))
        mItems.add(new Item("Option2", R.drawable.icons_for_option_2))
        mItems.add(new Item("Option3", R.drawable.icons_for_option_3))
        mItems.add("Secondary options")
        mItems.add(new Item("Option4", R.drawable.icons_for_option_4))
        // And so on...whatever the logic is.
    }

    @Override
    public int getItemCount() {
        return mItems.size();
    }

    @Override
    public int getItemViewType(int position) {
        if (position == 0 || position == 5) { // Assuming that the topmost item and the 5th item are the section headers. This if statement can be simplified too.
            return VIEW_TYPE_HEADER;
        } else {
            return VIEW_TYPE_REGULAR_ITEM;
        }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == VIEW_TYPE_HEADER) {
            return new HeaderViewHolder(mInflater.inflate(R.layout.list_item_header, parent, false));
        } else {
            return new RegularItemViewHolder(mInflater.inflate(R.layout.list_item_regular, parent, false));
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof HeaderViewHolder) {
            ((HeaderViewHolder) holder).setup(mItems.get(position));
        } else if (holder instanceof RegularItemViewHolder) {
            ((RegularItemViewHolder) holder).setup(mItems.get(position));
        }
    }


    private static class RegularItemViewHolder extends RecyclerView.ViewHolder {

        private RegularItemViewHolder(View convertView) {
            super(convertView);
            // Initialize your views here. Let's say you will have a TextView and an icon here or whatever else.
        }

        public void setup(Item item) {
            // Update your views here, etc.
        }
    }

    private static class HeaderViewHolder extends RecyclerView.ViewHolder {

        TextView titleTextView;

        private HeaderViewHolder(View convertView) {
            super(convertView);
            titleTextView = convertView.findViewById(R.id.section_header);
        }

        public void setup(String sectionHeaderTitle) {
            yourTextView.setText(title);
        }
    }
}

就是这样。对于最终的错误，我很抱歉，我没有测试代码。

干杯!