Android实现ViewPager无限循环效果（一）

package com.xiaomai.myproject.demo;import android.os.Bundle;import android.os.Handler;import android.support.v4.view.ViewPager;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import com.xiaomai.myproject.R;import com.xiaomai.myproject.adapter.LoopViewPagerAdapter;import com.xiaomai.myproject.base.BaseActivity;import com.xiaomai.myproject.utils.Utils;import java.util.ArrayList;import java.util.List;/** * Created by XiaoMai on 2016/10/7 17:19. *  */public class LoopViewPagerDemoActivity extends BaseActivity { /**  * 更新图片的时间  */ private static final int UPDATE_TIME = 3 * 1000; private ViewPager mViewPager; private LoopViewPagerAdapter mLoopViewPager; /**  * 图片资源集合  */ private int[] mImageIds; /**  * 图片集合  */ private List<ImageView> mImageList; /**  * 当前广告的index  */ private int mCurrentPageIndex; /**  * 指示Point  */ private LinearLayout mLinearLayoutPoints; private Handler mHandler = new Handler(); @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState); } @Override protected void onResume() {  super.onResume();  mHandler.postDelayed(myRunnable, UPDATE_TIME); } @Override protected void onPause() {  super.onPause();  mHandler.removeCallbacks(myRunnable); } Runnable myRunnable = new Runnable() {  @Override  public void run() {   mViewPager.setCurrentItem(mCurrentPageIndex + 1);  } }; @Override protected void initVariables() {  super.initVariables(); } @Override protected void initViews() {  mLinearLayoutPoints = (LinearLayout) findViewById(R.id.activity_ll_container);  mViewPager = (ViewPager) findViewById(R.id.activity_loop_viewpager); } @Override protected void loadData() {  super.loadData();  mHandler.postDelayed(new Runnable() {   @Override   public void run() {    /**     * 初始化图片的资源id     */    mImageIds = new int[]{      R.mipmap.ic_launcher,      R.mipmap.ic_launcher,      R.drawable.my_toast,      R.drawable.my_toast};    /**     * 添加ImageView     */    mImageList = new ArrayList<>();    //额外添加两张图片    int pagerCount = mImageIds.length + 2;    ViewGroup.LayoutParams layoutParams =      new ViewGroup.LayoutParams(        ViewGroup.LayoutParams.MATCH_PARENT,        ViewGroup.LayoutParams.WRAP_CONTENT);    for (int i = 0; i < pagerCount; i++) {     ImageView imageView = new ImageView(mContext);     imageView.setLayoutParams(layoutParams);     mImageList.add(imageView);    }    //圆点的直径    int diameter = Utils.dip2px(mContext,10f);    LinearLayout.LayoutParams params =      new LinearLayout.LayoutParams(diameter, diameter);    int margin = Utils.dip2px(mContext,5f);    params.setMargins(margin,margin,margin,margin);    mLinearLayoutPoints.removeAllViews();    for (int i = 0; i < mImageList.size(); i++) {     View view = new View(mContext);     view.setLayoutParams(params);     if (i != 0 && i != mImageList.size() - 1) {      view.setBackgroundResource(R.drawable.circle_normal);     }     mLinearLayoutPoints.addView(view);    }    mLinearLayoutPoints.setVisibility(View.VISIBLE);    mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {     @Override     public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {     }     @Override     public void onPageSelected(int position) {      mHandler.removeCallbacks(myRunnable);      mHandler.postDelayed(myRunnable, UPDATE_TIME);      mCurrentPageIndex = position;      if (position == 0) {       // 当视图在第一个时，将页面号设置为图片的最后一张。       mCurrentPageIndex = mImageIds.length;      } else if (position == mImageIds.length + 1) {       // 当视图在最后一个时,将页面号设置为图片的第一张。       mCurrentPageIndex = 1;      } else {      }      /**       * 当视图在第一个或者最后一个时，pageIndex和position的值不相等，       * 所以要改变viewPager的当前item。       */      if (position != mCurrentPageIndex) {       /**        * 第二参数必须设置为false，意思是立即过渡，不给用户视觉上的效果。        */       mViewPager.setCurrentItem(mCurrentPageIndex, false);       return;      }      for (int i = 1; i < mLinearLayoutPoints.getChildCount() - 1; i++) {       if (i != mCurrentPageIndex){        mLinearLayoutPoints.getChildAt(i).setBackgroundResource(R.drawable.circle_normal);       }else {        mLinearLayoutPoints.getChildAt(mCurrentPageIndex).setBackgroundResource(          R.drawable.circle_select);       }      }     }     @Override     public void onPageScrollStateChanged(int state) {     }    });    /**     * 当ViewPager被按下的时候，取消自动滚动     * 反之开启自动滑动。     */    mViewPager.setOnTouchListener(new View.OnTouchListener() {     @Override     public boolean onTouch(View v, MotionEvent event) {      if(event.getAction() == MotionEvent.ACTION_DOWN){       mHandler.removeCallbacks(myRunnable);      }else if (event.getAction() == MotionEvent.ACTION_UP){       mHandler.postDelayed(myRunnable, UPDATE_TIME);      }      return false;     }    });    mLoopViewPager = new LoopViewPagerAdapter(mImageList, mImageIds);    mViewPager.setAdapter(mLoopViewPager);    /**     * 因为第0个item是另外添加的那张图片，所以初始化时要把当前item设置为1。     */    mViewPager.setCurrentItem(1);    dissMissProgressDialog();   }  }, 3 * 1000); } @Override protected int getContentLayout() {  return R.layout.act_loopviewpager; }}

package com.xiaomai.myproject.adapter;import android.support.v4.view.PagerAdapter;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import java.util.List;/** * Created by XiaoMai on 2016/10/7 17:23. */public class LoopViewPagerAdapter extends PagerAdapter { private List<ImageView> mImageList; private int[] mImageIds; public LoopViewPagerAdapter(List<ImageView> mImageList, int[] mImageIds) {  this.mImageList = mImageList;  this.mImageIds = mImageIds; } @Override public int getCount() {  return mImageList == null ? 0 : mImageList.size(); } @Override public boolean isViewFromObject(View view, Object object) {  return view == object; } @Override public Object instantiateItem(ViewGroup container, int position) {  if (position == 0) {   // 如果是第0个item就设置它的图片内容为最后一个图片的内容   mImageList.get(position).setImageResource(mImageIds[mImageIds.length-1]);  } else if (position == (mImageList.size() - 1)) {   // 如果是最后一个item就设置它的图片内容为第一个图片的内容   mImageList.get(position).setImageResource(mImageIds[0]);  } else {   // 这是正常的图片   mImageList.get(position).setImageResource(mImageIds[position - 1]);  }  container.addView(mImageList.get(position));  return mImageList.get(position); } @Override public void destroyItem(ViewGroup container, int position, Object object) {  container.removeView(mImageList.get(position)); }}

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <include  android:id="@+id/titleBar"  layout="@layout/my_app_bar" /> <android.support.v4.view.ViewPager  android:id="@+id/activity_loop_viewpager"  android:layout_width="match_parent"  android:layout_height="200dp"  android:layout_below="@id/titleBar" /> <LinearLayout  android:id="@+id/activity_ll_container"  android:layout_width="match_parent"  android:orientation="horizontal"  android:gravity="center"  android:background="@color/toast"  android:layout_alignBottom="@id/activity_loop_viewpager"  android:visibility="gone"  android:layout_height="40dp"/></RelativeLayout>