Android ViewPager实现图片轮翻效果

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。

import java.util.ArrayList;
import java.util.List; 

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView; 

public class MainActivity extends Activity implements OnPageChangeListener { 

 protected static final String TAG = "MainActivity";
 private List<ImageView> imageViewList;
 private ViewPager mViewPager;
 private final int[] imageResIDs = {
   R.drawable.a,
   R.drawable.b,
   R.drawable.c,
   R.drawable.d,
   R.drawable.e
 };
 private final String[] 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",
   "热血屌丝的反杀"
 };
 private TextView tvImageDescription; // 图片描述
 private LinearLayout llPointGroup;  // 点控件的组
 private int previousPosition = 0;  // viewpager选中的前一个position
 private boolean isStop = false; // 控制循环的子线程是否停止 

 private Handler handler = new Handler(){ 

  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg); 

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

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

  initView(); 

  new Thread(new Runnable() { 

   @Override
   public void run() {
    // 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
 protected void onDestroy() {
  isStop = true;
  super.onDestroy();
 } 

 private void initView() {
  mViewPager = (ViewPager) findViewById(R.id.viewpager);
  llPointGroup = (LinearLayout) findViewById(R.id.ll_point_group);
  tvImageDescription = (TextView) findViewById(R.id.tv_image_description); 

  imageViewList = new ArrayList<ImageView>(); 

  ImageView iv;
  View pointView;
  LayoutParams params;
  for (int i = 0; i < imageResIDs.length; i++) {
   iv = new ImageView(this);
   iv.setBackgroundResource(imageResIDs[i]);
   imageViewList.add(iv); 

   // 根据图片添加点
   pointView = new View(this);
   params = new LayoutParams(5, 5);
   params.leftMargin = 5;
   pointView.setLayoutParams(params);
   pointView.setEnabled(false);
   pointView.setBackgroundResource(R.drawable.point_bg);
   llPointGroup.addView(pointView);
  } 

  MyPagerAdapter mAdapter = new MyPagerAdapter();
  mViewPager.setAdapter(mAdapter);
  mViewPager.setOnPageChangeListener(this); 

  int item = (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
 } 

 class MyPagerAdapter extends PagerAdapter { 

  @Override
  public int getCount() {
   return Integer.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
  public boolean isViewFromObject(View arg0, Object arg1) {
   return arg0 == arg1;
  } 

  /**
   * 需要销毁的对象的position传进来
   */
  @Override
  public void destroyItem(ViewGroup container, int position, 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
  public Object instantiateItem(ViewGroup container, int position) {
   // 添加指定position的对象
   mViewPager.addView(imageViewList.get(position % imageViewList.size()));
   return imageViewList.get(position % imageViewList.size());
  }
 } 

 @Override
 public void onPageScrollStateChanged(int arg0) {
  // TODO Auto-generated method stub 

 } 

 @Override
 public void onPageScrolled(int arg0, float arg1, int arg2) {
  // 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
 public void onPageSelected(int position) {
  tvImageDescription.setText(imageDescriptions[position % imageViewList.size()]);
  llPointGroup.getChildAt(position % imageViewList.size()).setEnabled(true);
  llPointGroup.getChildAt(previousPosition).setEnabled(false); 

  previousPosition = position % imageViewList.size();
 }
} 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。