Android 利用ViewPager实现图片可以左右循环滑动效果附代码下载

首先给大家展示靓照，对效果图感兴趣的朋友可以继续往下阅读哦。

ViewPager这个小demo实现的是可以左右循环滑动图片，下面带索引，滑到最后一页在往右滑动就要第一页，第一页往左滑动就到最后一页，上面是效果图，用美女图片是我一贯的作风，呵呵

 1.    首先看一些layout下的xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:orientation="vertical" >
 <android.support.v4.view.ViewPager
 android:id="@+id/viewPager"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content" />
 <RelativeLayout
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:orientation="vertical" >
 <LinearLayout
 android:id="@+id/viewGroup"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:layout_alignParentBottom="true"
 android:layout_marginBottom="30dp"
 android:gravity="center_horizontal"
 android:orientation="horizontal" >
 </LinearLayout>
 </RelativeLayout>
</FrameLayout> 

使用ViewPager首先需要引入android-support-v4.jar这个jar包。自己不要忘记加

package com.example.viewpagerdemo;
import android.app.Activity;
import android.os.Bundle;
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.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class TwoActivity extends Activity implements OnPageChangeListener{
 /**
 * ViewPager
 */
 private ViewPager viewPager;
 /**
 * 装点点的ImageView数组
 */
 private ImageView[] tips;
 /**
 * 装ImageView数组
 */
 private ImageView[] mImageViews;
 /**
 * 图片资源id
 */
 private int[] imgIdArray ;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 ViewGroup group = (ViewGroup)findViewById(R.id.viewGroup);
 viewPager = (ViewPager) findViewById(R.id.viewPager);
 //载入图片资源ID
 imgIdArray = new int[]{R.drawable.item01, R.drawable.item02, R.drawable.item03, R.drawable.item04,
 R.drawable.item05,R.drawable.item06, R.drawable.item07, R.drawable.item08};
 //将点点加入到ViewGroup中
 tips = new ImageView[imgIdArray.length];
 for(int i=0; i<tips.length; i++){
 ImageView imageView = new ImageView(this);
 imageView.setLayoutParams(new LayoutParams(10,10));
 tips[i] = imageView;
 if(i == 0){
 tips[i].setBackgroundResource(R.drawable.page_indicator_focused);
 }else{
 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused);
 }
 LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT,
  LayoutParams.WRAP_CONTENT));
 layoutParams.leftMargin = 5;
 layoutParams.rightMargin = 5;
 group.addView(imageView, layoutParams);
 }
 //将图片装载到数组中
 mImageViews = new ImageView[imgIdArray.length];
 for(int i=0; i<mImageViews.length; i++){
 ImageView imageView = new ImageView(this);
 mImageViews[i] = imageView;
 imageView.setBackgroundResource(imgIdArray[i]);
 }
 //设置Adapter
 viewPager.setAdapter(new MyAdapter());
 //设置监听，主要是设置点点的背景
 viewPager.setOnPageChangeListener(this);
 //设置ViewPager的默认项, 设置为长度的100倍，这样子开始就能往左滑动
 viewPager.setCurrentItem((mImageViews.length) * 100);
 }
 /**
 *
 * @author xiaanming
 *
 */
 public class MyAdapter extends PagerAdapter{
 @Override
 public int getCount() {
 return Integer.MAX_VALUE;
 }
 @Override
 public boolean isViewFromObject(View arg0, Object arg1) {
 return arg0 == arg1;
 }
 @Override
 public void destroyItem(View container, int position, Object object) {
 ((ViewPager)container).removeView(mImageViews[position % mImageViews.length]);
 }
 /**
 * 载入图片进去，用当前的position 除以 图片数组长度取余数是关键
 */
 @Override
 public Object instantiateItem(View container, int position) {
 ((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0);
 return mImageViews[position % mImageViews.length];
 }
 }
 @Override
 public void onPageScrollStateChanged(int arg0) {
 }
 @Override
 public void onPageScrolled(int arg0, float arg1, int arg2) {
 }
 @Override
 public void onPageSelected(int arg0) {
 setImageBackground(arg0 % mImageViews.length);
 }
 /**
 * 设置选中的tip的背景
 * @param selectItems
 */
 private void setImageBackground(int selectItems){
 for(int i=0; i<tips.length; i++){
 if(i == selectItems){
 tips[i].setBackgroundResource(R.drawable.page_indicator_focused);
 }else{
 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused);
 }
 }
 }
} 

喜欢的朋友直接下载代码哦。代码下载

上面的代码中，当只有3张图片或者2张图片的时候，滑动存在BUG问题的修改如下

destroyItem(View container, int position, Object object)方法中不removeView

 @Override
 public void destroyItem(View container, int position, Object object) {
// ((ViewPager)container).removeView(mImageViews[position % mImageViews.length]);
 }
instantiateItem(View container, int position)增加异常扑捉
[java] view plaincopy在CODE上查看代码片派生到我的代码片
@Override
 public Object instantiateItem(View container, int position) {
 try {
 ((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0);
 }catch(Exception e){
 //handler something
 }
 return mImageViews[position % mImageViews.length];
 } 

以上代码给大家展示了Android 利用ViewPager实现图片可以左右循环滑动效果，希望大家喜欢。