RecyclerView三种类型

样式布局

<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <size android:height="0dp" android:width="1dp"></size>
    <solid android:color="@android:color/holo_red_light"></solid>
</shape>

异步下载类

class MyTask extends AsyncTask<String,String,String> {
    @Override
    protected String doInBackground(String... strings) {
        try {
            URL url = new URL(strings[0]);
            HttpURLConnection hu = (HttpURLConnection) url.openConnection();
            hu.connect();
            int cod = hu.getResponseCode();
            if(cod == 200){
                InputStream is = hu.getInputStream();
                StringBuffer sb = new StringBuffer();
                int l = 0;
                byte[] b = new byte[1024];
                while((l = is.read(b)) != -1){
                    sb.append(new String(b,0,l));
                }
                return sb.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

布局文件和子布局

主布局

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Demo">

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rlist"
        ></android.support.v7.widget.RecyclerView>

</android.support.constraint.ConstraintLayout>

子布局

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"
    >

    <RelativeLayout
        android:layout_width="200dp"
        android:layout_height="100dp"
        android:id="@+id/lay"
        android:background="#0ff"
        >
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/img"
            android:src="@drawable/ic_launcher_background"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/titles"
            android:layout_toRightOf="@id/img"
            android:text="123"
            />
    </RelativeLayout>

</RelativeLayout>

主类

public class Demo extends AppCompatActivity {

    RVAdapter adapter;
    RecyclerView rlist;
    ArrayList<Map<String,String>> lists = new ArrayList<>();

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo);

        rlist = findViewById(R.id.rlist);

        String ss = "http://www.qubaobei.com/ios/cf/dish_list.php?stage_id=1&limit=10&page=1";
        try {
            //异步下载
            String s = new MyTask().execute(ss).get();
            //解析赋值方法
            init(s);
        } catch (ExecutionException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        //瀑布流
        StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
        //网格布局
//        GridLayoutManager manager = new GridLayoutManager(this,2);
        //线性布局
//        LinearLayoutManager manager = new LinearLayoutManager(this);
        manager.setOrientation(LinearLayoutManager.VERTICAL);//指定布局方向
        rlist.setLayoutManager(manager);//设置布局

        //设置样式布局
        DividerItemDecoration decoration = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL);
        decoration.setDrawable(getDrawable(R.drawable.divider_style));
        rlist.addItemDecoration(decoration);

        //设置动画
        DefaultItemAnimator animator = new DefaultItemAnimator();
        //设置时长
        animator.setAddDuration(1000);
        animator.setRemoveDuration(1000);
        rlist.setItemAnimator(animator);

        //适配器
        adapter = new RVAdapter(this, lists);
        rlist.setAdapter(adapter);

    }

    public void init(String ss){
        try {
            JSONObject jo = new JSONObject(ss);
            JSONArray data = jo.getJSONArray("data");
            for (int i = 0; i < data.length(); i++) {
                JSONObject o = data.getJSONObject(i);
                String title = o.getString("title");
                String pic = o.getString("pic");
                HashMap<String, String> map = new HashMap<>();
                map.put("title",title);
                map.put("pic",pic);
                lists.add(map);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

适配器

public class RVAdapter extends RecyclerView.Adapter<RVAdapter.RVHolder> {

    Context context;
    ArrayList<Map<String,String>> lists;
    RVLister lister;

    public RVAdapter(Context context, ArrayList<Map<String, String>> lists) {
        this.context = context;
        this.lists = lists;
    }

    @NonNull
    @Override
    public RVHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(context).inflate(R.layout.item, viewGroup,false);
        return new RVHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull RVHolder rvHolder, final int i) {

        Map<String, String> map = lists.get(i);
        rvHolder.titles.setText(map.get("title"));
        Picasso.with(context).load(map.get("pic")).into(rvHolder.img);

//瀑布流设置高度，瀑布流专用
       // int max = (int) (Math.random()*101+100);
       // ViewGroup.LayoutParams params = rvHolder.lay.getLayoutParams();
       // params.height = max;
      //  rvHolder.lay.setLayoutParams(params);

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

    class RVHolder extends RecyclerView.ViewHolder{

        TextView titles;
        ImageView img;
        RelativeLayout lay;

        public RVHolder(@NonNull View itemView) {
            super(itemView);
            titles = itemView.findViewById(R.id.titles);
            img = itemView.findViewById(R.id.img);
            lay = itemView.findViewById(R.id.lay);
        }
    }
}

效果图

线性布局效果图

网格布局效果图

瀑布流效果图