ViewPager实现图片轮翻效果，,很多App都有这种效果，

ViewPager实现图片轮翻效果，,很多App都有这种效果，

很多App都有这种效果，特别一些电商类的App，顶部每隔几秒钟会向右翻页显示下张图片，用来作推广或者内容展示用的。今天来简单地模仿一下，还自带一个自动跳动的小功能（底部有几个小点，图片移动的时候，点的状态也在变化），用定时器来实现不难。```java

import java.util.ArrayList;import java.util.concurrent.Executors;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v4.view.ViewPager.OnPageChangeListener;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;public class MainActivity extends Activity {    private int imageIds[];    private String[] titles;    private ArrayList<ImageView> images;    private ArrayList<View> dots;    private TextView title;    private ViewPager mViewPager;    private ViewPagerAdapter adapter;    private int oldPosition = 0;//记录上一次点的位置    private int currentItem; //当前页面    private ScheduledExecutorService scheduledExecutorService;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //图片ID        imageIds = new int[]{            R.drawable.a,            R.drawable.b,            R.drawable.c,            R.drawable.d,            R.drawable.e        };        //图片标题        titles = new String[]{            "巩俐不低俗，我就不能低俗",            "扑树又回来啦！再唱经典老歌引万人大合唱",            "揭秘北京电影如何升级",            "乐视网TV版大派送",            "热血屌丝的反杀"        };        //显示的图片        images = new ArrayList<ImageView>();        for(int i =0; i < imageIds.length; i++){            ImageView imageView = new ImageView(this);            imageView.setBackgroundResource(imageIds[i]);            images.add(imageView);        }        //显示的点        dots = new ArrayList<View>();        dots.add(findViewById(R.id.dot_0));        dots.add(findViewById(R.id.dot_1));        dots.add(findViewById(R.id.dot_2));        dots.add(findViewById(R.id.dot_3));        dots.add(findViewById(R.id.dot_4));        title = (TextView) findViewById(R.id.title);        title.setText(titles[0]);        mViewPager = (ViewPager) findViewById(R.id.vp);        adapter = new ViewPagerAdapter();        mViewPager.setAdapter(adapter);        mViewPager.setOnPageChangeListener(new OnPageChangeListener() {            @Override            public void onPageSelected(int position) {                title.setText(titles[position]);                dots.get(oldPosition).setBackgroundResource(R.drawable.dot_normal);                dots.get(position).setBackgroundResource(R.drawable.dot_focused);                oldPosition = position;                currentItem = position;            }            @Override            public void onPageScrolled(int arg0, float arg1, int arg2) {            }            @Override            public void onPageScrollStateChanged(int arg0) {            }        });    }    private class ViewPagerAdapter extends PagerAdapter {        @Override        public int getCount() {            return images.size();        }        //是否是同一张图片        @Override        public boolean isViewFromObject(View arg0, Object arg1) {            return arg0 == arg1;        }        @Override        public void destroyItem(ViewGroup view, int position, Object object) {            view.removeView(images.get(position));        }        @Override        public Object instantiateItem(ViewGroup view, int position) {            view.addView(images.get(position));            return images.get(position);        }    }    @Override    protected void onStart() {        // TODO Auto-generated method stub        super.onStart();        scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();        //每隔2秒钟切换一张图片        scheduledExecutorService.scheduleWithFixedDelay(new ViewPagerTask(), 2, 2, TimeUnit.SECONDS);    }    //切换图片    private class ViewPagerTask implements Runnable {        @Override        public void run() {            currentItem = (currentItem +1) % imageIds.length;            //更新界面            handler.obtainMessage().sendToTarget();        }    }    private Handler handler = new Handler(){        @Override        public void handleMessage(Message msg) {            //设置当前页面            mViewPager.setCurrentItem(<span style="font-family: Arial, Helvetica, sans-serif;">currentItem</span><span style="font-family: Arial, Helvetica, sans-serif;">);</span>        }    };}

```