Android开发之ViewPager实现滑动切换页面

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="Http://schemas.android.com/apk/res/android"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:orientation="vertical">

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


</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android1="http://schemas.android.com/apk/res/android"
    android1:layout_height="match_parent"
    android1:layout_width="match_parent"
    android1:background="@color/purple_200"
    android1:orientation="vertical">

    <TextView
        android1:textSize="30sp"
        android1:text="layout1"
        android1:layout_width="wrap_content"
        android1:layout_height="wrap_content"/>


</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android1="http://schemas.android.com/apk/res/android"
    android1:layout_height="match_parent"
    android1:layout_width="match_parent"
    android1:background="@color/purple_500"
    android1:orientation="vertical">

    <TextView
        android1:textSize="30sp"
        android1:text="layout2"
        android1:layout_width="wrap_content"
        android1:layout_height="wrap_content"/>


</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android1="http://schemas.android.com/apk/res/android"
    android1:layout_height="match_parent"
    android1:layout_width="match_parent"
    android1:background="@color/purple_700"
    android1:orientation="vertical">

    <TextView
        android1:textSize="30sp"
        android1:text="layout3"
        android1:layout_width="wrap_content"
        android1:layout_height="wrap_content"/>


</LinearLayout>

package com.example.myviewpager;

import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager.widget.ViewPager;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;

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);

        LayoutInflater inflater = getLayoutInflater().from(this);
        View view1 = inflater.inflate(R.layout.layout1,null);
        View view2 = inflater.inflate(R.layout.layout2,null);
        View view3 = inflater.inflate(R.layout.layout3,null);

        List<View> viewList = new ArrayList<>();
        viewList.add(view1);
        viewList.add(view2);
        viewList.add(view3);

        ViewPager viewpager = findViewById(R.id.viewpager);
        MyAdapter myadapter = new MyAdapter(viewList);
        viewpager.setAdapter(myadapter);

    }
}

private List<View> listview;

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

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

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

@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(listview.get(position));
    }