Usage of RecyclerView

首先RecyclerViewIt is a container-type control.

​​​​​​​ is a new control for large data display,可以用来代替传统的ListView,更加强大和灵活.”

什么时候使用RecyclerView？

        当数据结构(列表)足够大的时候,You need to use the container nature of the control

        从android5.0Beginning Google released a new control for the display of large amounts of data,can be stored dynamically.

There are three layouts,线性布局,Grid layout and waterfall flow

重点 

        RecyclerView的创建以及使用,And how to switch the trying mode

RecyclerView的使用方法

1.现在activity的xml文件中使用RecycleView控件

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

2.创建RecycleView的子项目

 3.Add the controls that need to be added to the container and layout them in the subproject（Because this sub-project is equivalent to the existence of a template,This template will be put into the container as a whole）

<ImageView
        android:id="@+id/iv_img"
        android:layout_width="55dp"
        android:layout_height="55dp"
        app:srcCompat="@mipmap/list" />

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginLeft="5dp"
        android:text="TextView" />

4.The next step is to use an adapter,创建一个.Java类并且继承RecyclerView.Adapter,Note that methods of abstract classes cannot be implemented directly here,需要自己创建一个ViewHoldermethod and inheritRecyclerView.ViewHolder

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

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

    }

    @Override
    public int getItemCount() {
        return 0;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }
}

5.在ViewHodlerBind the control in the method

public class ViewHolder extends RecyclerView.ViewHolder {
        View view;
        ImageView mailImg;
        TextView mailName;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            view=itemView;
            mailImg=itemView.findViewById(R.id.iv_img);
            mailName=itemView.findViewById(R.id.tv_name);
        }
    }

 6.Get which page is called

public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view=LayoutInflater.from(parent.getContext()).inflate(R.layout.mail_item,parent,false);
        ViewHolder viewHolder=new ViewHolder(view);
        return viewHolder;
    }

7.Because there are several pages to be determined according to the incoming data,So to create with list参数的构造方法

private List<Mail_item> mList;
    public MailAdapter(List<Mail_item> mList) {
        this.mList = mList;
    }

//这个方法就是根据list的长度来确定,Create several screens
@Override
    public int getItemCount() {
        return mList.size();
    }

8.设置控件属性

@Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Mail_item mail=mList.get(position);
        holder.mailImg.setImageResource(mail.getImg());
       
        holder.mailName.setText(mail.getName());
       
    }

 9.在acticaty设置控件属性

    private String[] names={"张一","张二","张三","李一","李二","李三","李四","王一","王二","王三","王四","王五","小明","小亮"};
    private int[] imgs={R.mipmap.a_1,R.mipmap.a_2,R.mipmap.a_3,R.mipmap.a_4,R.mipmap.a_5,R.mipmap.a_6,R.mipmap.a_7,R.mipmap.a_8,R.mipmap.a_9,R.mipmap.a_10,R.mipmap.a_11,R.mipmap.a_12,R.mipmap.a_13,R.mipmap.a_14};

10.The loop puts the value into the control

private void initDate() {
        for (int i=0;i<names.length;i++){
            Mail_item mail=new Mail_item(names[i],imgs[i]);
            list.add(mail);
        }
    }

11.设置RecycleView

initDate();

        rv_view=findViewById(R.id.rv_view);
        RecyclerView recyclerView=findViewById(R.id.rv_view);

        LinearLayoutManager layoutManager=new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        MailAdapter mailAdapter=new MailAdapter(list);
        recyclerView.setAdapter(mailAdapter);

扩展

ViewPager2轮播图,是继承与RecycleViewA new container control for

使用方法和RecycleView雷同

主要是在ActivityThe implementation in the code-behind is different

vr_swiper=findViewById(R.id.vr_swiper);

        ListSwiper listSwiper=new ListSwiper();
        list=listSwiper.initDate();
        SwiperAdapter adapter=new SwiperAdapter(list);
        CompositePageTransformer cpt=new CompositePageTransformer();
        //Add spacing when sliding
        cpt.addTransformer(new MarginPageTransformer(20));
        //Added zoom on swipe
        cpt.addTransformer(new ScaleInTransformer());
        vr_swiper.setOffscreenPageLimit(1);
        //一屏多页
        View view = vr_swiper.getChildAt(0);
        if(view != null && view instanceof RecyclerView){
            view.setPadding(100, 0, 100, 0);
            ((RecyclerView) view).setClipToPadding(false);
        }
        vr_swiper.setPageTransformer(cpt);
        vr_swiper.setAdapter(adapter);

initDate()代码如下：