作用

实现翻页的效果。

1、在activity_main.xml中创建ViewPager

<?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="match_parent"
    android:orientation="vertical">

    <androidx.viewpager.widget.ViewPager
        android:id="@+id/vp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

2、创建3个layout.xml文件页面

练习代码，每个页面代码相同，此处只给1个，其余复制粘贴即可。

<?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="match_parent"
    android:background="#ff00ffff"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="layout1"
        android:textSize="30sp" />

</LinearLayout>

3、MainActivity.java

package com.example.myapplication;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.viewpager.widget.ViewPager;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//        获取布局并渲染
        LayoutInflater lf = getLayoutInflater().from(this);
        View view1 = lf.inflate(R.layout.layout1,null);
        View view2 = lf.inflate(R.layout.layout2,null);
        View view3 = lf.inflate(R.layout.layout3,null);

//        将三个页面view添加到List集合中
        List<View> viewList = new ArrayList<>();
        viewList.add(view1);
        viewList.add(view2);
        viewList.add(view3);
        
//        创建适配器对象并添加到ViewPager中
        ViewPager vp = findViewById(R.id.vp);
        MyAdapter myAdapter = new MyAdapter(viewList);
        vp.setAdapter(myAdapter);


    }
}

4、创建适配器

package com.example.myapplication;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

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

import java.util.List;

public class MyAdapter extends PagerAdapter {
    private List<View> mListView;

    public MyAdapter(List<View> mListView) {
        this.mListView = mListView;
    }

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        container.addView(mListView.get(position),0);
        return mListView.get(position);
    }

    @Override
    public int getCount() {
        return mListView.size();
    }

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
        return view == object;
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView(mListView.get(position));
    }
}