图片轮播

activity_main

<?xml version="1.0" encoding="utf-8"?><RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"    android:layout_height="match_parent" tools:context="com.example.zidonglunbo.MainActivity">    <android.support.v4.view.ViewPager        android:id="@+id/vp"        android:layout_width="match_parent"        android:layout_height="200dp">    </android.support.v4.view.ViewPager>    <LinearLayout        android:id="@+id/linpoint"        android:orientation="horizontal"        android:gravity="center"        android:layout_alignBottom="@+id/vp"        android:layout_width="match_parent"        android:layout_height="wrap_content">    </LinearLayout></RelativeLayout>

my_point_selected(drawable文件夹下)

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval">    <solid android:color="#00f"></solid></shape>

my_point_unselected(drawable文件夹下)

<?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>

MainActivity

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=vp.getCurrentItem();            vp.setCurrentItem(index+1);            //改变小圆点            setSelectedPoint(index+1);            //延迟发送消息            sendEmptyMessageDelayed(1,2000);        }    };    private ViewPager vp;    private LinearLayout linpoint;    private List<String> list;    private ImageView[] imageView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        vp = (ViewPager) findViewById(R.id.vp);        linpoint = (LinearLayout) findViewById(R.id.linpoint);        list = new ArrayList<>();        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1505151721118&di=649c9a43aed72fbc4d99ec1a031510c6&imgtype=0&src=http%3A%2F%2Fimg.zcool.cn%2Fcommunity%2F015c7d574b9f8f6ac72525aee98351.jpg");        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1505151956771&di=0eb6f306991d24b67a13ceb336f80102&imgtype=0&src=http%3A%2F%2Fi0.hdslb.com%2Fbfs%2Farchive%2F00613def3f1beb7a35ae136341be2b589bc46a2d.jpg_320x200.jpg");        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1505151847685&di=c7a4b5d08ec43fa629bcb690039a7629&imgtype=0&src=http%3A%2F%2Fattimg.dospy.com%2Fimg%2Fday_080625%2F20080625_2e91a10c444877e88827vri2ZKdGMvQo.jpg");        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1505151825129&di=70bf74b87d8a15cb91a2d79f15ed0eaf&imgtype=0&src=http%3A%2F%2Fattimg.dospy.com%2Fimg%2Fday_081016%2F20081016_fee215664d5740e56c13E2YB8giERFEX.jpg");        list.add("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1505746504&di=930c4d677a02328a142d6fa85ed14580&imgtype=jpg&er=1&src=http%3A%2F%2Fattimg.dospy.com%2Fimg%2Fday_090113%2F20090113_6ac58b42bea94f0b318e1B6BZb5lPZl5.jpg");        imageView = new ImageView[list.size()];        vp.setAdapter(new MyAdapter(this,list));        vp.setCurrentItem(list.size()*100);        //实现自动播放        myHandler.sendEmptyMessageDelayed(1,2000);        initPoint();    }    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){                imageView[i].setImageResource(R.drawable.my_point_selected);//小红点            }else{                imageView[i].setImageResource(R.drawable.my_point_unselected);//小灰点            }        }    }    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.my_point_selected);//第二步            }else{                img.setImageResource(R.drawable.my_point_unselected);            }            //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            imageView[i]=img;        }    }}

AndroidManifest

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.zidonglunbo">    <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">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

ImageUtils

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;public class ImageUtils {    public static void initImageLoader(Context context){        File file = context.getExternalCacheDir();        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(file))//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);    }    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;    }}

MyApplication

import android.app.Application;public class MyApplication extends Application{    @Override    public void onCreate() {        super.onCreate();        ImageUtils.initImageLoader(this);    }}

MyAdapter

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;public class MyAdapter extends PagerAdapter{    private Context context;    private List<String> list;    public MyAdapter(Context context, List<String> list) {        this.context = context;        this.list = list;    }    @Override    public int getCount() {        return Integer.MAX_VALUE;    }    @Override    public boolean isViewFromObject(View view, Object object) {        return view==object;    }    @Override    public Object instantiateItem(ViewGroup container, int position) {        ImageView img=new ImageView(context);        img.setScaleType(ImageView.ScaleType.FIT_XY);        ImageLoader.getInstance().displayImage(list.get(position%list.size()),img,ImageUtils.getImageoptions());        container.addView(img);        return img;    }    @Override    public void destroyItem(ViewGroup container, int position, Object object) {        container.removeView((View) object);    }}