Handler实现轮播

首先写入网络权限
导入imagerlouder的jar包
布局
activity的布局

   <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:orientation="vertical"        >        <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:id="@+id/linear"            android:orientation="horizontal"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_alignBottom="@+id/vp"            ></LinearLayout>    </RelativeLayout>

drawable文件夹中的布局
point_selected.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval"    >    <solid  android:color="#f00"></solid></shape>

point_unselected.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval"    >    <solid  android:color="#fff"></solid></shape>

Activity主方法里边

package com.example.denmo21;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.support.v4.view.ViewPager;import android.support.v7.app.AppCompatActivity;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.ListView;import com.handmark.pulltorefresh.library.PullToRefreshScrollView;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private ImageView[] imgarray;    private PullToRefreshScrollView psv;    private ViewPager vp;    private ListView lv;    private String url = "http://pic8.nipic.com/20100701/5290458_114840036316_2.jpg";    private String url2 = "http://pic2.nipic.com/20090424/1468853_230119053_2.jpg";    private String url3 = "http://img3.3lian.com/2013/s1/20/d/57.jpg";    private String url4 = "http://pic39.nipic.com/20140226/18071023_164300608000_2.jpg";    private String url5 = "http://a0.att.hudong.com/15/08/300218769736132194086202411_950.jpg";    private LinearLayout linear;    private List<String> pagelist;    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            int index = vp.getCurrentItem();            vp.setCurrentItem(index + 1);            getinitimg(index + 1);//改变xioayd            sendEmptyMessageDelayed(1, 2000);        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        psv = (PullToRefreshScrollView) findViewById(R.id.psv);        vp = (ViewPager) findViewById(R.id.vp);        lv = (ListView) findViewById(R.id.lv);        linear = (LinearLayout) findViewById(R.id.linear);        pagelist = new ArrayList<>();        pagelist.add(url);        pagelist.add(url2);        pagelist.add(url3);        pagelist.add(url4);        pagelist.add(url5);        MyPage myPage = new MyPage(this, pagelist);        vp.setAdapter(myPage);        vp.setCurrentItem(pagelist.size() * 100);        imgarray = new ImageView[pagelist.size()];        handler.sendEmptyMessageDelayed(1, 1000);        initimg();//初始化小圆点    }    public void getinitimg(int index) {        int selectindex = index % pagelist.size();        for (int i = 0; i < pagelist.size(); i++) {            if (i == selectindex) {                imgarray[i].setImageResource(R.drawable.point_selected);            } else {                imgarray[i].setImageResource(R.drawable.point_unselected);            }        }    }    /**     * 初始化小圆点     */    public void initimg() {        for (int i = 0; i < pagelist.size(); i++) {            ImageView img = new ImageView(this);            img.setScaleType(ImageView.ScaleType.FIT_XY);            if (i == 0) {                img.setImageResource(R.drawable.point_selected);            } else {                img.setImageResource(R.drawable.point_unselected);            }            //设置小圆点的大小            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(20, 20);            params.setMargins(0, 0, 10, 10);//设置间距            linear.addView(img, params);            imgarray[i] = img;        }    }}

适配器
MyPage

package com.example.denmo21;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;/** * Created by zld on 2017/12/21. */public class MyPage extends PagerAdapter {    private Context context;    private List<String> pagelist;    public MyPage(Context context, List<String> pagelist) {        this.context = context;        this.pagelist = pagelist;    }    @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(pagelist.get(position % pagelist.size()), img);        container.addView(img);        return img;    }    @Override    public void destroyItem(ViewGroup container, int position, Object object) {        container.removeView((View) object);    }}

MyApption

package com.example.denmo21;import android.app.Application;import com.nostra13.universalimageloader.core.ImageLoader;import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;/** * Created by zld on 2017/12/21. */public class MyApption extends Application {    @Override    public void onCreate() {        super.onCreate();        ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(this).build();        ImageLoader.getInstance().init(configuration);    }}