RecyclerView添加头布局和尾布局

1,添加一个头布局

效果图

• 1,Xml布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_linear_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="20dp"/>
</android.support.constraint.ConstraintLayout>

• 2,Activity

public class RvLinearActivity2 extends AppCompatActivity {
    private RecyclerView rvlinearlist;
    private ArrayList<String> mData;
    private RvLinearAdapter2 mAdapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linear);
        this.rvlinearlist = (RecyclerView) findViewById(R.id.rv_linear_list);

        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        //设置方向,默认方向(垂直)
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        rvlinearlist.setLayoutManager(linearLayoutManager);

        mData = new ArrayList<>();
        for (int i = 0; i < 20; i++) {
            mData.add("频道"+i);
        }

        //直接在adapter里面加上了头布局
        mAdapter = new RvLinearAdapter2(this, mData);
        rvlinearlist.setAdapter(mAdapter);

        //自定义分割线,顶部有线
        rvlinearlist.addItemDecoration(new ListViewHeadDecoration
                (this,R.drawable.listview_decoration));
    }
}

• 3,Adapter

public class RvLinearAdapter2 extends  RecyclerView.Adapter<RecyclerView.ViewHolder>{

    private final LayoutInflater mLayoutInflater;
    private Context mContext;
    private List<String>mData;
    //Type
    private int TYPE_HEADER = 1001;
    public RvLinearAdapter2(Context context, List<String> data) {
        mContext = context;
        mData = data;
        mLayoutInflater = LayoutInflater.from(context);
    }
    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType==TYPE_HEADER){
            View headerView = mLayoutInflater.inflate(R.layout.header_rv_linear, parent, false);
            return new HeaderViewHolder(headerView);
        }
        View inflate = mLayoutInflater.inflate(R.layout.item_rv_linear, parent, false);
        return new ViewHolder(inflate);

    }
    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof ViewHolder){
            //postion==0被头布局占据
            ((ViewHolder) holder).tvText.setText(mData.get(position-1));
            ((ViewHolder) holder).tvText.setOnClickListener(view ->
                    Toast.makeText(mContext, mData.get(position-1), Toast.LENGTH_SHORT).show() );
        }
    }

    @Override
    public int getItemCount() {
        //加了头布局,多一个
        return mData.size()+1;
    }

    @Override
    public int getItemViewType(int position) {
        //在第一个位置添加头
        if (position==0){
            return TYPE_HEADER;
        }
        return super.getItemViewType(position);
    }


    /**
     * 头布局的viewholder
     */
    class HeaderViewHolder extends RecyclerView.ViewHolder {
        public HeaderViewHolder(View itemView) {
            super(itemView);
        }
    }


    /**
     * 正常内容的viewholder
     */
    class ViewHolder extends RecyclerView.ViewHolder {
        TextView tvText;
        public ViewHolder(View itemView) {
            super(itemView);
            tvText=itemView.findViewById(R.id.tv_item_rv_linear_text);
        }
    }
}

源码

2,添加一个头布局,一个尾布局

效果图

其他都一样,除了Adapter不同.

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


    private final LayoutInflater mLayoutInflater;
    private Context mContext;
    private List<String>mData;

    private final static int ITEM_HEADER=0;
    private final static int ITEM_CONTENT=1;
    private final static int ITEM_FOOT=2;

    /**
     * 头布局和尾布局的数量
     */
    private int mHeader=1;
    private int mFoot=1;

    public RvHFAdapter(Context context, List<String> data) {
        mContext = context;
        mData = data;
        mLayoutInflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType==ITEM_CONTENT){
            View view = mLayoutInflater.inflate(R.layout.item_rv_linear, parent, false);
            return new ViewHolder(view);
        }
        if (viewType==ITEM_HEADER){
            View view = mLayoutInflater.inflate(R.layout.header_rv_linear, parent, false);
            return new HeaderViewHolder(view);
        }
        if (viewType==ITEM_FOOT){
            View view = mLayoutInflater.inflate(R.layout.footer_rv_linear, parent, false);
            return new FooterViewHolder(view);
        }
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        //Log.e("MMM", "onBindViewHolder: "+position);

        if (holder instanceof ViewHolder){
            ((ViewHolder) holder).tvText.setText(mData.get(position-mHeader));
            ((ViewHolder) holder).tvText.setOnClickListener(view ->
                    Toast.makeText(mContext, mData.get(position-mHeader), Toast.LENGTH_SHORT).show());
        }
    }

    @Override
    public int getItemCount() {
        //固定数目,一个头,一个尾
        return mData.size()+mHeader+mFoot;
    }


    @Override
    public int getItemViewType(int position) {
        if (mHeader!=0&&position<mHeader){
            return ITEM_HEADER;
        }
        if (mFoot!=0&&position>=mData.size()+mHeader){
            return ITEM_FOOT;
        }
        return ITEM_CONTENT;
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        TextView tvText;
        public ViewHolder(View itemView) {
            super(itemView);
            tvText=itemView.findViewById(R.id.tv_item_rv_linear_text);
        }
    }
    class HeaderViewHolder extends RecyclerView.ViewHolder {
        public HeaderViewHolder(View itemView) {
            super(itemView);
        }
    }
    class FooterViewHolder extends RecyclerView.ViewHolder {
        public FooterViewHolder(View itemView) {
            super(itemView);
        }
    }
}

源码

3,网格布局添加头布局和尾布局

image.png

xml布局相同

• 1,Activity

public class GridActivity extends AppCompatActivity {
    private android.support.v7.widget.RecyclerView rvlinearlist;
    private ArrayList<String> mData;
    private GridAdapter mGridAdapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linear);
        this.rvlinearlist = (RecyclerView) findViewById(R.id.rv_linear_list);

        initData();

        initAdapter();

    }

    private void initAdapter() {
        GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
        rvlinearlist.setLayoutManager(gridLayoutManager);

        mGridAdapter = new GridAdapter(this, mData);
        //rvlinearlist.setAdapter(mGridAdapter);
        //使用添加头和尾的适配器
        RvHFAdapter rvHFAdapter = new RvHFAdapter(this, mData);
        rvlinearlist.setAdapter(rvHFAdapter);

        //处理头和尾布局,使其占据一行
        gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
            @Override
            public int getSpanSize(int position) {
                //判断是否是头或者尾布局
                if (position==0||position==mData.size()+1){
                    return gridLayoutManager.getSpanCount();
                }
                return 1;
            }
        });

        //添加分割线
        //rvlinearlist.addItemDecoration(new Divider2(this));
    }

    private void initData() {
        mData = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            mData.add("频道"+i);
        }
    }
}

• 2,Adapter

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


    private final LayoutInflater mLayoutInflater;
    private Context mContext;
    private List<String>mData;

    private final static int ITEM_HEADER=0;
    private final static int ITEM_CONTENT=1;
    private final static int ITEM_FOOT=2;

    /**
     * 头布局和尾布局的数量
     */
    private int mHeader=1;
    private int mFoot=1;

    public RvHFAdapter(Context context, List<String> data) {
        mContext = context;
        mData = data;
        mLayoutInflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType==ITEM_CONTENT){
            View view = mLayoutInflater.inflate(R.layout.item_rv_linear, parent, false);
            return new ViewHolder(view);
        }
        if (viewType==ITEM_HEADER){
            View view = mLayoutInflater.inflate(R.layout.header_rv_linear, parent, false);
            return new HeaderViewHolder(view);
        }
        if (viewType==ITEM_FOOT){
            View view = mLayoutInflater.inflate(R.layout.footer_rv_linear, parent, false);
            return new FooterViewHolder(view);
        }
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        //Log.e("MMM", "onBindViewHolder: "+position);

        if (holder instanceof ViewHolder){
            ((ViewHolder) holder).tvText.setText(mData.get(position-mHeader));
            ((ViewHolder) holder).tvText.setOnClickListener(view ->
                    Toast.makeText(mContext, mData.get(position-mHeader), Toast.LENGTH_SHORT).show());
        }
    }

    @Override
    public int getItemCount() {
        //固定数目,一个头,一个尾
        return mData.size()+mHeader+mFoot;
    }


    @Override
    public int getItemViewType(int position) {
        if (mHeader!=0&&position<mHeader){
            return ITEM_HEADER;
        }
        if (mFoot!=0&&position>=mData.size()+mHeader){
            return ITEM_FOOT;
        }
        return ITEM_CONTENT;
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        TextView tvText;
        public ViewHolder(View itemView) {
            super(itemView);
            tvText=itemView.findViewById(R.id.tv_item_rv_linear_text);
        }
    }
    class HeaderViewHolder extends RecyclerView.ViewHolder {
        public HeaderViewHolder(View itemView) {
            super(itemView);
        }
    }
    class FooterViewHolder extends RecyclerView.ViewHolder {
        public FooterViewHolder(View itemView) {
            super(itemView);
        }
    }
}

源码