Android RecyclerView增加头部Header和尾部Footer，并实现Item分组

忘是亡心i 2023-10-17 18:57 11阅读 0赞

**Android RecyclerView增加头部Header和尾部Footer，并实现Item分组**

如图所示：  
![20180405104146302][]

![20180405104158043][]

在Android的RecyclerView上实现增加若干头部Header和若干尾部Footer，关键是利用ViewType的类型，然后由本例的抽象类Item返回的类型加载不同的ViewHolder。  
代码：

package app.zhangphil.exp;
    
    import android.graphics.Color;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    import java.util.ArrayList;
    
    public class MainActivity extends AppCompatActivity {
    
        private final int TYPE_HEADER = 0xa00;
        private final int TYPE_GROUP = 0xa01;
        private final int TYPE_CHILD = 0xa02;
        private final int TYPE_FOOTER = 0xa03;
    
        private RecyclerViewAdapter mAdapter;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            RecyclerView recyclerView = findViewById(R.id.recycler_view);
    
            LinearLayoutManager layoutManage = new LinearLayoutManager(this);
            layoutManage.setOrientation(LinearLayoutManager.VERTICAL);
    
            recyclerView.setLayoutManager(layoutManage);
    
            mAdapter = new RecyclerViewAdapter();
            recyclerView.setAdapter(mAdapter);
    
            String[] groupNames = {"A", "B", "C", "D", "E", "F", "G"};
            for (int i = 0; i < groupNames.length; i++) {
                Group group = new Group();
                group.id = i;
                group.title = groupNames[i];
                mAdapter.addItem(group);
    
                int count = (int) (Math.random() * 10) % 3;
                for (int j = 0; j < count; j++) {
                    Child child = new Child();
                    child.position = j;
                    child.group = group;
                    mAdapter.addItem(child);
                }
            }
    
            addHeader();
            addFooter();
        }
    
        private void addHeader() {
            for (int i = 0; i < 3; i++) {
                HeaderItem headerItem = new HeaderItem();
                headerItem.id = i;
                mAdapter.addItem(i, headerItem); //增加一个头部，可以增加多个
            }
        }
    
        private void addFooter() {
            for (int i = 0; i < 3; i++) {
                FooterItem footerItem = new FooterItem();
                footerItem.id = i;
                mAdapter.addItem(footerItem); //增加一个尾部，可以增加多个
            }
        }
    
        public class RecyclerViewAdapter extends RecyclerView.Adapter<ItemVH> {
            private ArrayList<Item> items;
    
            public RecyclerViewAdapter() {
                items = new ArrayList<>();
            }
    
            @Override
            public ItemVH onCreateViewHolder(ViewGroup parent, int viewType) {
                View view;
                ItemVH itemVH = null;
                switch (viewType) {
                    case TYPE_HEADER:
                        view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
                        itemVH = new HeaderVH(view);
                        break;
    
                    case TYPE_FOOTER:
                        view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
                        itemVH = new FooterVH(view);
                        break;
    
                    case TYPE_GROUP:
                        view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
                        itemVH = new GroupVH(view);
                        break;
    
                    case TYPE_CHILD:
                        view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_2, parent, false);
                        itemVH = new ChildVH(view);
                        break;
                }
    
                return itemVH;
            }
    
            @Override
            public void onBindViewHolder(ItemVH holder, int position) {
                Item item = items.get(position);
                switch (getItemViewType(position)) {
                    case TYPE_HEADER:
                        HeaderItem headerItem = (HeaderItem) items.get(position);
                        HeaderVH headerVH = (HeaderVH) holder;
                        headerVH.text.setText("第" + headerItem.id + "个头部");
                        break;
    
                    case TYPE_FOOTER:
                        FooterItem footerItem = (FooterItem) items.get(position);
                        FooterVH footerVH = (FooterVH) holder;
                        footerVH.text.setText("第" + footerItem.id + "个尾部");
                        break;
    
                    case TYPE_GROUP:
                        Group g = (Group) item;
                        GroupVH groupVH = (GroupVH) holder;
                        groupVH.text.setText(g.title);
                        break;
    
                    case TYPE_CHILD:
                        Child c = (Child) item;
                        ChildVH childVH = (ChildVH) holder;
                        childVH.text1.setText(c.group.title);
                        childVH.text2.setText(c.position + "");
                        break;
                }
            }
    
            @Override
            public int getItemCount() {
                return items.size();
            }
    
            @Override
            public int getItemViewType(int position) {
                return items.get(position).getType();
            }
    
            public void addItem(Item item) {
                items.add(item);
            }
    
            public void addItem(int position, Item item) {
                items.add(position, item);
            }
        }
    
        private class Group extends Item {
            public String title;
    
            @Override
            public int getType() {
                return TYPE_GROUP;
            }
        }
    
        private class Child extends Item {
            public Group group;
    
            @Override
            public int getType() {
                return TYPE_CHILD;
            }
        }
    
        private abstract class Item {
            public int position;
            public int id;
    
            public abstract int getType();
        }
    
    
        private class FooterItem extends Item {
            @Override
            public int getType() {
                return TYPE_FOOTER;
            }
        }
    
        private class FooterVH extends ItemVH {
            public TextView text;
    
            public FooterVH(View itemView) {
                super(itemView);
                text = itemView.findViewById(android.R.id.text1);
                itemView.setBackgroundColor(Color.LTGRAY);
            }
    
            @Override
            public int getType() {
                return TYPE_FOOTER;
            }
        }
    
        private class HeaderItem extends Item {
            @Override
            public int getType() {
                return TYPE_HEADER;
            }
        }
    
        private class HeaderVH extends ItemVH {
            public TextView text;
    
            public HeaderVH(View itemView) {
                super(itemView);
                text = itemView.findViewById(android.R.id.text1);
                itemView.setBackgroundColor(Color.LTGRAY);
            }
    
            @Override
            public int getType() {
                return TYPE_HEADER;
            }
        }
    
        private class GroupVH extends ItemVH {
            public TextView text;
    
            public GroupVH(View itemView) {
                super(itemView);
                text = itemView.findViewById(android.R.id.text1);
                text.setBackgroundColor(Color.RED);
            }
    
            @Override
            public int getType() {
                return TYPE_GROUP;
            }
        }
    
        private class ChildVH extends ItemVH {
            public TextView text1;
            public TextView text2;
    
            public ChildVH(View itemView) {
                super(itemView);
                text1 = itemView.findViewById(android.R.id.text1);
                text2 = itemView.findViewById(android.R.id.text2);
                text1.setTextColor(Color.LTGRAY);
                text2.setTextColor(Color.BLUE);
            }
    
            @Override
            public int getType() {
                return TYPE_CHILD;
            }
        }
    
        private abstract class ItemVH extends RecyclerView.ViewHolder {
            public ItemVH(View itemView) {
                super(itemView);
            }
    
            public abstract int getType();
        }
    }

[20180405104146302]: https://img-blog.csdn.net/20180405104146302
[20180405104158043]: https://img-blog.csdn.net/20180405104158043