recyclerview的使用

本文详细介绍 RecyclerView 的使用方法,包括依赖导入、自定义适配器、实现多条目布局及点击事件处理等内容。同时提供了一个分割线装饰器的实现示例。

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recyclerview的使用之前必须导入依赖:

compile 'com.android.support:recyclerview-v7:23.4.0'

下面的适配器:可供参考:
public class myadpter1 extends RecyclerView.Adapter<myadpter1.holde>{
   public Context context;
    public List<Nai.ResultBean.BrandsBean.ProductsBean> products;

    public myadpter1(Context context, List<Nai.ResultBean.BrandsBean.ProductsBean> products) {
        this.context = context;
        this.products = products;
    }


    @Override
    public myadpter1.holde onCreateViewHolder(ViewGroup parent, int viewType) {
        View inflate = LayoutInflater.from(context).inflate(R.layout.recy_girst, parent, false);
       holde holde=new holde(inflate);
        return holde;
    }

    @Override
    public void onBindViewHolder(myadpter1.holde holder, int position) {
        Glide.with(context).load(products.get(position).getPic()).into(holder.image_recygrid);
        holder.text_recygrid.setText(products.get(position).getName());
    }

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

   public class holde extends RecyclerView.ViewHolder{

        private final ImageView image_recygrid;
        private final TextView text_recygrid;

        public holde(View itemView) {
            super(itemView);
            image_recygrid = (ImageView) itemView.findViewById(R.id.image_recygrid);
            text_recygrid = (TextView) itemView.findViewById(R.id.text_recygrid);
        }
    }
}
recyclerview 的多条目布局仅供参考:

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

    Context context;
    private List<Make.DataBean.SubjectsBean.GoodsListBean> goodsList;
    int type1=0;
    int type2=1;
  public  itemclink itemclink;
    public Recyviewadpter(Context context, List<Make.DataBean.SubjectsBean.GoodsListBean> goodsList) {
        this.context = context;
        this.goodsList = goodsList;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if(viewType==type1)
        {
            View inflate = View.inflate(context, R.layout.recy_spring, null);
      listadpter listadpter=new listadpter(inflate);


            return listadpter;
        }else if(viewType==type2){
            View inflate = View.inflate(context, R.layout.recy_spring_but, null);
        butadter butadter=new butadter(inflate);

            return butadter;
        }
        return null;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
        if(holder.getItemViewType()==type1)
        {
           listadpter listadpter= (listadpter) holder;
            Glide.with(context)
                    .load(goodsList.get(position).getGoods_img())
                    .into(listadpter.image_spring);
            listadpter.image_spring .setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(itemclink!=null)
                    {
                        itemclink.setOnoitemclink(v,position);
                    }
                }
            });
            listadpter.text_efficacy.setText(goodsList.get(position).getEfficacy()+"|");
            listadpter.text_goods_name.setText(goodsList.get(position).getGoods_name());
            listadpter.text_spring_price.setText("¥"+""+goodsList.get(position).getShop_price()+"|");
            listadpter.text_spring_oldprice.setText("¥"+goodsList.get(position).getMarket_price());
        }
        else if(holder.getItemViewType()==type2)
        {
          butadter  butadter=(butadter)holder;

        }

    }

    @Override
    public int getItemCount() {
        return 6;
    }

    public class listadpter extends RecyclerView.ViewHolder{

        private final ImageView image_spring;
        private final TextView text_efficacy;
        private final TextView text_spring_price;
        private final TextView text_spring_oldprice;
        private final TextView text_goods_name;

        public listadpter(View itemView) {
            super(itemView);
            image_spring = (ImageView) itemView.findViewById(R.id.image_spring);
            text_efficacy = (TextView) itemView.findViewById(R.id.text_efficacy);
            text_spring_price = (TextView) itemView.findViewById(R.id.text_spring_price);
            text_spring_oldprice = (TextView) itemView.findViewById(R.id.text_spring_oldprice);
            text_goods_name = (TextView) itemView.findViewById(R.id.text_goods_name);
        }
    }
    public class butadter extends RecyclerView.ViewHolder{

        private final ImageView image_but;

        public butadter(View itemView) {
            super(itemView);
            image_but = (ImageView) itemView.findViewById(R.id.image_but);

        }
    }

    @Override
    public int getItemViewType(int position) {
        if(position==5)
        {
            return  type2;

        }
        else{
            return type1;
        }

    }



    //recyview的点击事件
    public interface itemclink
    {
        void setOnoitemclink(View view,int position);
    }

    public void setOnitemclink(itemclink itemclink)
    {
        this.itemclink=itemclink;
    }
}

//下面是分割线的工具类:
package com.bawei.liujianrui.activity.activity;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by Administrator on 2017/4/24.
 */
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
    private static final int[] ATTRS = new int[]{
            android.R.attr.listDivider
    };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }


    public void drawVertical(Canvas c, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView v = new RecyclerView(parent.getContext());
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }
    
}

//使用的时候:分别写两次就可以。

recy.addItemDecoration(new DividerItemDecoration(this
     ,DividerItemDecoration.HORIZONTAL_LIST ));
 recy.addItemDecoration(new DividerItemDecoration(this
         ,DividerItemDecoration.VERTICAL_LIST ));

内容概要:该论文探讨了一种基于粒子群优化(PSO)的STAR-RIS辅助NOMA无线通信网络优化方法。STAR-RIS作为一种新型可重构智能表面,能同时反射和传输信号,与传统仅能反射的RIS不同。结合NOMA技术,STAR-RIS可以提升覆盖范围、用户容量和频谱效率。针对STAR-RIS元素众多导致获取完整信道状态信息(CSI)开销大的问题,作者提出一种在不依赖完整CSI的情况下,联合优化功率分配、基站波束成形以及STAR-RIS的传输和反射波束成形向量的方法,以最大化总可实现速率并确保每个用户的最低速率要求。仿真结果显示,该方案优于STAR-RIS辅助的OMA系统。 适合人群:具备一定无线通信理论基础、对智能反射面技术和非正交多址接入技术感兴趣的科研人员和工程师。 使用场景及目标:①适用于希望深入了解STAR-RIS与NOMA结合的研究者;②为解决无线通信中频谱资源紧张、提高系统性能提供新的思路和技术手段;③帮助理解PSO算法在无线通信优化问题中的应用。 其他说明:文中提供了详细的Python代码实现,涵盖系统参数设置、信道建模、速率计算、目标函数定义、约束条件设定、主优化函数设计及结果可视化等环节,便于读者理解和复现实验结果。此外,文章还对比了PSO与其他优化算法(如DDPG)的区别,强调了PSO在不需要显式CSI估计方面的优势。
### 使用RecyclerView实现列表视图 #### 创建并配置RecyclerView实例 为了在Android应用程序中使用`RecyclerView`显示列表视图,首先需要获取布局文件中的`RecyclerView`对象。这可以通过调用`findViewById()`方法完成: ```java RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view); ``` 接着要为`RecyclerView`指定一个适配器(Adapter),该适配器负责提供数据给各个子项(ItemView)[^1]。 #### 设置LayoutManager 为了让`RecyclerView`知道如何排列它的孩子视图(Child View), 需要设置一个`LayoutManager`. 常见的选择有线性布局(`LinearLayoutManager`)、网格布局(`GridLayoutManager`)以及瀑布流布局(`StaggeredGridLayoutManager`). 下面是一个简单的例子展示了如何应用线性布局管理器: ```java recyclerView.setLayoutManager(new LinearLayoutManager(this)); ``` #### 定义ViewHolder与Adapter 对于每一个条目来说, `RecyclerView`利用了一个叫做`ViewHolder`的设计模式来提高性能. 这里定义了持有单个item UI元素引用的静态内部类. 之后还需要编写自定义的`Adapter`, 继承自`RecyclerView.Adapter<MyAdapter.MyViewHolder>`, 并重写几个抽象的方法如`onCreateViewHolder()`,`onBindViewHolder()`, 和`getItemCount()` 来填充实际的数据到viewholder 中去[^3]. #### 数据绑定 当设置了adapter 后就可以准备向其中添加数据源了。一般情况下我们会有一个List 或者Array 类型的数据集作为输入传递给adapter 的构造函数,在每次更新界面的时候只需要刷新这个集合再通知adapter 即可。 ```java myDataset.add("New Item"); mAdapter.notifyItemInserted(myDataset.size()-1); ```
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