RecyclerView使用

activity_luncher

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ActivityLuncher">

<androidx.recyclerview.widget.RecyclerView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/linearRv"
    android:dividerHeight="10dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>`
item_2_layout
`<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/holo_blue_dark">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/item_2_tv"
        android:gravity="center"
        android:padding="10dp"/>
</LinearLayout>

item_layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/item_tv"
        android:gravity="center"
        android:padding="10dp"/>

</LinearLayout>

MainActivity

package com.example.luncherdemo1;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.StaggeredGridLayoutManager;

import android.os.Bundle;
import android.widget.LinearLayout;

import java.util.ArrayList;

public class ActivityLuncher extends AppCompatActivity {

    private ArrayList<String> mDatas = new ArrayList<>();

    private void initDatas(){
        for (int i=1;i<=100;i++){
            mDatas.add("第"+i+"个item");
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_luncher);
        initDatas();
        RecyclerView mRv = findViewById(R.id.linearRv);
        //网格
//        GridLayoutManager gridLayoutManager=new GridLayoutManager(this,8);
//        gridLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
//        mRv.setLayoutManager(gridLayoutManager);

        //瀑布流
        StaggeredGridLayoutManager staggeredGridLayoutManager=new StaggeredGridLayoutManager(5,StaggeredGridLayoutManager.HORIZONTAL);
        staggeredGridLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRv.setLayoutManager(staggeredGridLayoutManager);
        MyRecyclerAdapter adapter = new MyRecyclerAdapter(this,mDatas);
        mRv.setAdapter(adapter);

    }

}

MyRecyclerAdatper

package com.example.luncherdemo1;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

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

    private Context mContext;
    private ArrayList<String> mDatas;
    public MyRecyclerAdapter(Context context, ArrayList<String> datas){
        mContext = context;
        mDatas = datas;
    }
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
//        View itemView = LayoutInflater.from(mContext).inflate(R.layout.item_layout,parent,false);
        LayoutInflater inflater = LayoutInflater.from(mContext);
        if (viewType==ITEM_TYPE.ITEM_TYPE_ITEM.ordinal()){
            return new NormalHolder(inflater.inflate(R.layout.item_layout,parent,false));
        }
        return new SectionHolder(inflater.inflate(R.layout.item_2_layout,parent,false));
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof SectionHolder){
            SectionHolder sectionHolder = (SectionHolder) holder;
            sectionHolder.mSectionTV.setText("第"+((position/SECTION_ITEM_NUM)+1)+"组");
        }else if (holder instanceof NormalHolder){
            NormalHolder normalHolder=(NormalHolder) holder;
            normalHolder.mTV.setText(mDatas.get(position));
        }

    }
    public static enum ITEM_TYPE{
        ITEM_TYPE_SECTION,
        ITEM_TYPE_ITEM;
    }
    private int SECTION_ITEM_NUM = 10;

    @Override
    public int getItemViewType(int position) {
        if (position%SECTION_ITEM_NUM==0){
            return ITEM_TYPE.ITEM_TYPE_SECTION.ordinal();
        }
        return ITEM_TYPE.ITEM_TYPE_ITEM.ordinal();
    }

    @Override
    public int getItemCount() {
        return mDatas.size();
    }
    class NormalHolder extends RecyclerView.ViewHolder{
        TextView mTV;
        public NormalHolder(@NonNull View itemView) {
            super(itemView);
            mTV = (TextView) itemView.findViewById(R.id.item_tv);
            mTV.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Toast.makeText(mContext,mTV.getText(), Toast.LENGTH_SHORT).show();
                }
            });
        }
    }
    class SectionHolder extends RecyclerView.ViewHolder{
        TextView mSectionTV;
        public SectionHolder(@NonNull View itemView) {
            super(itemView);
            mSectionTV = (TextView) itemView.findViewById(R.id.item_2_tv);
        }
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.luncherdemo1">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.LuncherDemo">
        <activity
            android:name=".ActivityLuncher"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>