Android：ViewPager详解

Android：ViewPager详解

• • 准备3个页面
  • 创建ViewPager
  • Java代码中获取ViewPager对象
  • 创建Adapter
  • 在main方法中调用Adapter

准备3个页面

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#ffff0000"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <TextView
        android:gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="页面1"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#ffffff00"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <TextView
        android:gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="页面2"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#ff00ffff"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <TextView
        android:gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="页面3"/>
</LinearLayout>

创建ViewPager

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

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

</LinearLayout>

Java代码中获取ViewPager对象

package com.example.viewpager01;

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

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ViewPager viewPager = findViewById(R.id.view);
    }
}

创建Adapter

package com.example.viewpager01;

import android.view.View;

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

import java.util.List;

public class ViewAdapter extends PagerAdapter {

    private List<View> myListView;

    public ViewAdapter(List<View> myListView) {
        this.myListView = myListView;
    }

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

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

在main方法中调用Adapter

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

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