viewpager无限轮播（从网络上获取图片小圆点）

import android.content.Context;
import android.graphics.Bitmap;

import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;

import java.io.File;

/**
 * Created by e531 on 2017/11/13.
 */
public class ImageUtils {

    /**
     * 对ImageLoader进行初使化
     * @param context
     */
    public static void initImageLoader(Context context){

        File cacheFile=context.getExternalCacheDir();//android认为的缓存目录

        ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(context)
                .memoryCacheExtraOptions(480, 800)//缓存图片最大的长和宽
                .threadPoolSize(2)//线程池的数量
                .threadPriority(4)
                .memoryCacheSize(2*1024*1024)//设置内存缓存区大小
                .diskCacheSize(20*1024*1024)//设置sd卡缓存区大小
                .diskCache(new UnlimitedDiscCache(cacheFile))//自定义缓存目录
                .writeDebugLogs()//打印日志内容
                .diskCacheFileNameGenerator(new Md5FileNameGenerator())//给缓存的文件名进行md5加密处理
                .build();

        ImageLoader.getInstance().init(configuration);

    }

    /**
     * 得到图片的显示设置类
     * @return
     */
    public static DisplayImageOptions getImageOptions(){

        DisplayImageOptions options=new DisplayImageOptions.Builder()
                .cacheInMemory(true)//使用内存缓存
                .cacheOnDisk(true)//使用磁盘缓存
                .bitmapConfig(Bitmap.Config.RGB_565)//设置图片的色彩模式
                .imageScaleType(ImageScaleType.EXACTLY)//设置图片的缩放方式
                .build();
        return options;

    }


}

创建一个utils，建立一个ImageUtils初始化，

2.

public class MyApplication  extends Application{

    @Override
    public void onCreate() {
        super.onCreate();

        //进行初使化
        ImageUtils.initImageLoader(this);
    }
}

3.

import android.content.Context;
import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import com.nostra13.universalimageloader.core.ImageLoader;

import java.util.List;

import cuishihao.bwie.com.lianxi2.utils.ImageUtils;


/**
 * Created by e531 on 2017/11/13.
 */
public class MyPagerAdapter  extends PagerAdapter{


    private Context context;
    //    private int[] imgArray=new int[]{R.mipmap.a0,R.mipmap.a1,R.mipmap.a2};
    //用于存放网络图片的url地址
    private List imgUrl;


    public MyPagerAdapter(Context context,List imgUrl) {
        this.context = context;
        this.imgUrl=imgUrl;
    }

    //返回页面的数量
    @Override
    public int getCount() {
        return Integer.MAX_VALUE;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view==object;
    }

    //0~getCount返回的值-1
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        //返回当前显示的视图
        ImageView imageView = new ImageView(context);
        //图片的绽放方式
        imageView.setScaleType(ImageView.ScaleType.FIT_XY);

        //0,1,2
//        imageView.setImageResource(imgArray[position%imgArray.length]);

        //使用ImageLoader下载图片
        ImageLoader.getInstance().displayImage(imgUrl.get(position%imgUrl.size()),
                imageView, ImageUtils.getImageOptions());

        //添加到容器
        container.addView(imageView);

        return imageView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {

        container.removeView((View) object);
    }
}

4.

import android.os.Handler;
import android.os.Message;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.LinearLayout;

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

public class MainActivity extends AppCompatActivity {

    private Handler myHandler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            //获取当前正在显示的页面
            int index=viewPager.getCurrentItem();
            viewPager.setCurrentItem(index+1);

            //改变小圆点
            setSelectedPoint(index+1);

            //延迟发送消息
            sendEmptyMessageDelayed(1,2000);

        }
    };
    private ViewPager viewPager;
    private LinearLayout linPoint;
    private ImageView[] imgArray;

    private List list;

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

        viewPager = (ViewPager) findViewById(R.id.vp);
        linPoint = (LinearLayout) findViewById(R.id.linpoint);


        //数据.....装的是path路径
        list = new ArrayList<>();
        list.add("https://ss0.bdstatic.com/94oJfD_bAAcT8t7mm9GUKT-xh_/timg?image&quality=100&size=b4000_4000&sec=1510576227&di=8c199118d3ece98e0565e9ae0c751894&src=http://www.5577.com/up/2017-8/15029516238492643.jpg");
        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1510585834296&di=a42b00c2d1c5b2903960ecc5c391a5a0&imgtype=0&src=http%3A%2F%2Fwww.5577.com%2Fup%2F2017-8%2F15029516239761152.jpg");
        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1510585834296&di=fdb5e7f458f947ad1cdb3154a152de6e&imgtype=0&src=http%3A%2F%2Fwx1.sinaimg.cn%2Forj480%2F006Keh8Jly1fidr0yrc7xj30hs0a0jrl.jpg");
        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1510585834295&di=a9198d0f22ff74259f71557bee091d6f&imgtype=0&src=http%3A%2F%2Fwww.xz7.com%2Fup%2F2017-8%2F201781085651764760.jpg");
        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1510585834295&di=a2098f90037db615b7fef2ae0f100173&imgtype=0&src=http%3A%2F%2F1.pic.pc6.com%2Fthumb%2Fup%2F2017-08%2F15016384112136643_600_0.jpg");

        imgArray=new ImageView[list.size()];

        viewPager.setAdapter(new MyPagerAdapter(this,list));

        //使页面 可以向左滑动
        viewPager.setCurrentItem(list.size()*100);

        //实现自动播放
        myHandler.sendEmptyMessageDelayed(1,2000);

        initPoint();

    }

    //0,1,2,3,4,......Integer.maxvalue
    public  void setSelectedPoint(int pageIndex){
        //循环imageview控件
        //计算要选中小圆点的下标
        int selectedIndex=pageIndex%list.size();

        for(int i=0;i<list.size();i++){
            if(i==selectedIndex){

                imgArray[i].setImageResource(R.drawable.point_selected);
            }else{

                imgArray[i].setImageResource(R.drawable.point_un_selected);
            }
        }

    }

    /**
     * 初使化小圆点
     */
    private void initPoint() {
        for(int i=0;i<list.size();i++){
            //第一步
            ImageView img=new ImageView(this);
            //图片的缩放方式
            img.setScaleType(ImageView.ScaleType.FIT_XY);
            if(i==0){
                //使用shape画小圆点

                img.setImageResource(R.drawable.point_un_selected);
            }else{
                img.setImageResource(R.drawable.point_un_selected);
            }
            //img对象 设置控件的宽度与高度
            LinearLayout.LayoutParams params=new LinearLayout.LayoutParams(30,30);
            //设置右间隔 10px
            params.setMargins(0,0,10,0);
            //添加到容器中
            linPoint.addView(img,params);//第三步
            //添加到数组中
            imgArray[i]=img;

        }


    }
}

5.创建视图

xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    tools:context="cuishihao.bwie.com.lianxi2.MainActivity">

    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:id="@+id/vp">android.support.v4.view.ViewPager>

    

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/linpoint"
        android:gravity="center"
        android:layout_alignBottom="@+id/vp">

    LinearLayout>




RelativeLayout>

6. 自动轮播时 小圆点的颜色，在value中

xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5color>
    <color name="colorPrimaryDark">#303F9Fcolor>
    <color name="colorAccent">#FF4081color>
resources>

xml version="1.0" encoding="utf-8"?>
<resources>resources>

<resources>

    
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        
        <item name="colorPrimary">@color/colorPrimaryitem>
        <item name="colorPrimaryDark">@color/colorPrimaryDarkitem>
        <item name="colorAccent">@color/colorAccentitem>
    style>

resources>

7. 在drawable中 建立两个 一个是轮播选中是 一个是没选中

  选中point_selected 

xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="#ff0000">solid>

shape>

没选中是point_un_selected

xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="#ccc">solid>

shape>

8.在权限中

<uses-permission android:name="android.permission.INTERNET">uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE">uses-permission>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE">uses-permission>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    android:name=".MyApplication"
    >

还要记得导入imaged的jar包