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android RecyclerView

程序员文章站 2022-04-09 18:32:57
引用 在项目的build.gradle添加依赖 RecyclierView使用的基本方法 recyclerView.setAdapter(); 添加适配器(必须) recyclerView.setLayoutManager(); 选择一种布局(必须) recyclerAdapter.setHeade ......

引用

在项目的build.gradle添加依赖

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

recyclierview使用的基本方法

recyclerview.setadapter(); 添加适配器(必须)

recyclerview.setlayoutmanager(); 选择一种布局(必须)

recycleradapter.setheaderview(); 添加头布局

recycleradapter.setfooterview(); 添加底部布局

recyclerview.setitemanimator(new defaultitemanimator()); 添加默认动画

recyclerview.additemdecoration(); 添加分割线

layout manager布局管理器

1.三种布局管理器:

new linearlayoutmanager(this, linearlayoutmanager.vertical, false) 以垂直或者水平列表方式展示item,第三个参数是否颠倒数据显示

new gridlayoutmanager(this,4)  以网格方式展示item,第二个参数代表列数

new staggeredgridlayoutmanager(4, staggeredgridlayoutmanager.horizontal)  以瀑布流方式展示item,第一个参数代表列数

2.常用方法

canscrollhorizontally();//能否横向滚动
canscrollvertically();//能否纵向滚动
scrolltoposition(int position);//滚动到指定位置
setorientation(int orientation);//设置滚动的方向
getorientation();//获取滚动方向
findviewbyposition(int position);//获取指定位置的item view
findfirstcompletelyvisibleitemposition();//获取第一个完全可见的item位置
findfirstvisibleitemposition();//获取第一个可见item的位置
findlastcompletelyvisibleitemposition();//获取最后一个完全可见的item位置
findlastvisibleitemposition();//获取最后一个可见item的位置

 adapter适配器模板

recyclerview必须自定义适配器,并且自己创建事件监听,布局和数据的绑定顺序,每个item都会执行一遍:getiitemviewtype(绑定类型) > oncreateviewholder(选择布局类型) > onbindviewholder(绑定数据)

notifyiteminserted(position);插入一个item

notifyitemremoved(position); 移除一个item

notifyitemchanged(position) 刷新item

public class datarecycleradapter extends recyclerview.adapter<datarecycleradapter.myviewholder>{
    private list<string> list;
    private context context;
    private list<integer> mheights;
    private static int type_title=0;
    private static int type_footer=1;
    private static int type_content =2;
    private view mheaderview;
    private view mfooterview;

    public datarecycleradapter(context context, list<string> list) {
        this.list=list;
        mheights = new arraylist<>();
        this.context=context;
    }

    //根据不同的类型适应不用的布局
    @override
    public myviewholder oncreateviewholder(viewgroup parent, int viewtype) {
        if(mheaderview != null && viewtype == type_title) {
            return new myviewholder(mheaderview);
        }
        if(mfooterview != null && viewtype == type_footer) {
            return new myviewholder(mfooterview);
        }
        return new myviewholder(layoutinflater.from(context).inflate(r.layout.options_item3,parent,false));
    }

    //给item分布不同的类型
    @override
    public int getitemviewtype(int position) {
        if (position == 0){
            return type_title;
         }else if(position==list.size()){
            return type_footer;
        }else{
            return type_content;
        }
    }

    public view getheaderview() {
        return mheaderview;
    }
    //添加自定义的头部
    public void setheaderview(view headerview) {
        mheaderview = headerview;
        notifyiteminserted(0);
    }

    public view getfooterview() {
        return mfooterview;
    }
    //添加自定义底部
    public void setfooterview(view footerview) {
        mfooterview = footerview;
        notifyiteminserted(list.size()+1);
    }
    //主体布局
    @override
    public void onbindviewholder(final myviewholder holder, int position) {
        if(getitemviewtype(position) != type_content) {
            return;
        }
            holder.textview.settext(list.get(position-1));

        if (monitemclicklitener != null){
            holder.itemview.setonclicklistener(new view.onclicklistener(){
                @override
                public void onclick(view v){
                    int pos = holder.getlayoutposition();
                    monitemclicklitener.onitemclick(holder.itemview, pos);
                }
            });

            holder.itemview.setonlongclicklistener(new view.onlongclicklistener(){
                @override
                public boolean onlongclick(view v){
                    int pos = holder.getlayoutposition();
                    monitemclicklitener.onitemlongclick(holder.itemview, pos);
                    return true;
                }
            });
        }
    }

    //获取item总数
    @override
    public int getitemcount() {
         if(mfooterview !=null){
            return list.size()+1;
        }else {
            return list.size();
        }
    }
    //监听器接口
    public interface onitemclicklitener{
        void onitemclick(view view, int position);
        void onitemlongclick(view view , int position);
    }

    private onitemclicklitener monitemclicklitener;

    public void setonmyitemclicklitener(onitemclicklitener monitemclicklitener) {
        this.monitemclicklitener = monitemclicklitener;
    }

   //头和底部的布局
    class myviewholder extends recyclerview.viewholder {
        private textview textview;
        myviewholder(view itemview) {
            super(itemview);
            if (itemview == mheaderview||itemview == mfooterview){
                return;
            }
            textview= (textview) itemview.findviewbyid(r.id.options_tv);
            textview.settext("uuu");
        }
    }
    //模拟新增的数据
    public void adddata(int position) {
        list.add(position, "insert 数据");
        notifyiteminserted(position+1);
        toast.maketext(context,""+list.size(),toast.length_short).show();
    }
    //移除一个布局
    public void removedata(int position) {
        list.remove(position);
        notifyitemremoved(position);
    }

实例

private void initdatarecycleradapter(){
    recycleradapter=new datarecycleradapter(this,mdata);
    //布局管理器
    recyclerview.setlayoutmanager( new linearlayoutmanager(this, linearlayoutmanager.vertical, false));
    //分割线
    recyclerview.additemdecoration(new divideritemdecoration(this,
            divideritemdecoration.horizontal));
    //使用默认动画
    recyclerview.setitemanimator(new defaultitemanimator());
    //不使用默认的布局类型,添加自定义头部布局
    recycleradapter.setheaderview(layoutinflater.from(this).inflate(r.layout.options_title, recyclerview, false));
    //不使用默认的布局类型,添加自定义底部布局
    layoutinflater inflater= layoutinflater.from(this);
    view footerview = inflater.inflate(r.layout.options_footer, null);
    recycleradapter.setfooterview(footerview);
    //底部布局事件,增加一个item
    footerview.setonclicklistener(new view.onclicklistener() {
        @override
        public void onclick(view view) {
            toast.maketext(mainactivity.this,"展开",toast.length_short).show();
            recycleradapter.adddata(mdata.size());
        }
    });
    recyclerview.setadapter(recycleradapter);
    recycleradapter.setonmyitemclicklitener(new datarecycleradapter.onitemclicklitener() {
        //item的点击事件,移除一个item
        @override
        public void onitemclick(view view, int position) {
            recycleradapter.removedata(position);
            toast.maketext(mainactivity.this,""+mdata.size(),toast.length_short).show();
        }
        //item的长按事件,显示item下标
        @override
        public void onitemlongclick(view view, int position) {
            toast.maketext(mainactivity.this,"第"+position+"个",toast.length_short).show();
        }
    });
}
//模拟数据源
private void adddata(){
    mdata= new arraylist<>();
    for (int i=1;i<20;i++) {
        mdata.add("数据"+i+"个");
    }
}