ViewPager

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.ViewPagerandroid: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"><TextViewandroid: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 {@Overrideprotected 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@Overridepublic Object instantiateItem(@NonNull ViewGroup container, int position) {container.addView(mListView.get(position),0);return mListView.get(position);}@Overridepublic int getCount() {return mListView.size();}@Overridepublic boolean isViewFromObject(@NonNull View view, @NonNull Object object) {return view == object;}@Overridepublic void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {container.removeView(mListView.get(position));}
}