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);     }     } }