Android ViewPager实现图片轮翻效果

importjava.util.ArrayList;

importjava.util.List;

importandroid.app.Activity;

importandroid.os.Bundle;

importandroid.os.Handler;

importandroid.os.Message;

importandroid.os.SystemClock;

importandroid.support.v4.view.PagerAdapter;

importandroid.support.v4.view.ViewPager;

importandroid.support.v4.view.ViewPager.OnPageChangeListener;

importandroid.util.Log;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.ImageView;

importandroid.widget.LinearLayout;

importandroid.widget.LinearLayout.LayoutParams;

importandroid.widget.TextView;

publicclassMainActivityextendsActivityimplementsOnPageChangeListener {

 protectedstaticfinalString TAG ="MainActivity";

 privateListimageViewList;

 privateViewPager mViewPager;

 privatefinalint[] imageResIDs = {

   R.drawable.a,

   R.drawable.b,

   R.drawable.c,

   R.drawable.d,

   R.drawable.e

 };

 privatefinalString[] imageDescriptions = {

   "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?潘康姆瓷?quot;

 };

 privateTextView tvImageDescription;// 图片描述

 privateLinearLayout llPointGroup; // 点控件的组

 privateintpreviousPosition =0; // viewpager选中的前一个position

 privatebooleanisStop =false;// 控制循环的子线程是否停止

 privateHandler handler =newHandler(){

  @Override

  publicvoidhandleMessage(Message msg) {

   super.handleMessage(msg);

   mViewPager.setCurrentItem(mViewPager.getCurrentItem() +1);

  }

 };

 @Override

 protectedvoidonCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);

  initView();

  newThread(newRunnable() {

   @Override

   publicvoidrun() {

    // 每两秒钟向主线程发送一条消息, 切换viewpager的界面

    while(!isStop) {

     SystemClock.sleep(2000);

     handler.sendEmptyMessage(0);

    }

    Log.i(TAG,"循环线程停止了");

   }}).start();

 }

 @Override

 protectedvoidonDestroy() {

  isStop =true;

  super.onDestroy();

 }

 privatevoidinitView() {

  mViewPager = (ViewPager) findViewById(R.id.viewpager);

  llPointGroup = (LinearLayout) findViewById(R.id.ll_point_group);

  tvImageDescription = (TextView) findViewById(R.id.tv_image_description);

  imageViewList =newArrayList();

  ImageView iv;

  View pointView;

  LayoutParams params;

  for(inti =0; i < imageResIDs.length; i++) {

   iv =newImageView(this);

   iv.setBackgroundResource(imageResIDs[i]);

   imageViewList.add(iv);

   // 根据图片添加点

   pointView =newView(this);

   params =newLayoutParams(5,5);

   params.leftMargin =5;

   pointView.setLayoutParams(params);

   pointView.setEnabled(false);

   pointView.setBackgroundResource(R.drawable.point_bg);

   llPointGroup.addView(pointView);

  }

  MyPagerAdapter mAdapter =newMyPagerAdapter();

  mViewPager.setAdapter(mAdapter);

  mViewPager.setOnPageChangeListener(this);

  intitem = (Integer.MAX_VALUE /2) - ((Integer.MAX_VALUE /2) % imageViewList.size());

  mViewPager.setCurrentItem(item); // 设置当前选中的item的position

  tvImageDescription.setText(imageDescriptions[previousPosition]);

  llPointGroup.getChildAt(previousPosition).setEnabled(true);// 第一点被选中

 }

 classMyPagerAdapterextendsPagerAdapter {

  @Override

  publicintgetCount() {

   returnInteger.MAX_VALUE;

  }

  /**

   * 移动的对象和进来的对象如果是同一个就返回true, 代表复用view对象

   * false 使用object对象

   */

  @Override

  publicbooleanisViewFromObject(View arg0, Object arg1) {

   returnarg0 == arg1;

  }

  /**

   * 需要销毁的对象的position传进来

   */

  @Override

  publicvoiddestroyItem(ViewGroup container,intposition, Object object) {

   // 移除掉指定position的对象

   mViewPager.removeView(imageViewList.get(position % imageViewList.size()));

  }

  /**

   * 加载position位置的view对象

   */

  @Override

  publicObject instantiateItem(ViewGroup container,intposition) {

   // 添加指定position的对象

   mViewPager.addView(imageViewList.get(position % imageViewList.size()));

   returnimageViewList.get(position % imageViewList.size());

  }

 }

 @Override

 publicvoidonPageScrollStateChanged(intarg0) {

  // TODO Auto-generated method stub

 }

 @Override

 publicvoidonPageScrolled(intarg0,floatarg1,intarg2) {

  // TODO Auto-generated method stub

 }

 /**

  * 当viewpager页面切换时回调

  * @param position 就是当前显示的page页

  */

 @Override

 publicvoidonPageSelected(intposition) {

  tvImageDescription.setText(imageDescriptions[position % imageViewList.size()]);

  llPointGroup.getChildAt(position % imageViewList.size()).setEnabled(true);

  llPointGroup.getChildAt(previousPosition).setEnabled(false);

  previousPosition = position % imageViewList.size();

 }

}