Android使用ViewPager实现图片滑动预览效果

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.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="com.example.blog_0615.MainActivity"> 
 
  <android.support.v4.view.ViewPager 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:id="@+id/vp_main_viewpager" 
    ></android.support.v4.view.ViewPager> 
 
</android.support.constraint.ConstraintLayout> 

package com.example.blog_0615; 
 
import android.support.v4.view.PagerAdapter; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ImageView; 
 
import java.util.ArrayList; 
import java.util.List; 
 
public class MainActivity extends AppCompatActivity { 
 
  //定义图片数组 
  private int images[]={R.drawable.bird,R.drawable.cat,R.drawable.chicken}; 
  //定义一个View的数组 
  private List<View> views=new ArrayList<>(); 
  private ViewPager vp_main_viewpager; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
 
    vp_main_viewpager = (ViewPager) findViewById(R.id.vp_main_viewpager); 
 
    //将images数组中的图片放入ImageView 
    for (int i = 0; i < images.length; i++) { 
      ImageView imageView=new ImageView(this); 
      imageView.setImageResource(images[i]); 
      views.add(imageView); 
    } 
 
    //为ViewPager设置适配器 
    vp_main_viewpager.setAdapter(new MyAdapter()); 
  } 
 
  class MyAdapter extends PagerAdapter { 
 
    @Override 
    public int getCount() { 
      return views.size(); 
    } 
 
    @Override 
    public boolean isViewFromObject(View view, Object object) { 
      return view==object; 
    } 
 
    @Override 
    public Object instantiateItem(ViewGroup container, int position) { 
      View v=views.get(position); 
      container.addView(v); 
 
      return v; 
    } 
 
    @Override 
    public void destroyItem(ViewGroup container, int position, Object object) { 
      View v=views.get(position); 
      //前一张图片划过后删除该View 
      container.removeView(v); 
    } 
 
 
  } 
}