封装一个ViewPager真正的实现图片无限循环滚动带导航点

效果图：

大家在写项目的过程中常常会碰到须要实现Viewpager里面载入几张图片来循环自己主动轮播的效果，假设不封装一下的话代码分散在activity里面会显得非常乱。并且也不利于我们下次复用，所以这里我把viewpager的相关代码抽取出来放在了一个类里面，使用的时候仅仅须要new 这个对象就可以。

直接看代码：

MyViewPager.java类：在activity中仅仅须要在初始化数据的时候增加MyViewPager myViewPager=new MyViewPager(this)这段代码就ok。

package com.duora.bobge.duoradeliverly_version2.custom_view;

import android.app.Activity;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.duora.bobge.duoradeliverly_version2.R;
import com.duora.bobge.duoradeliverly_version2.adapter.EventPageAdapter;
import com.duora.bobge.duoradeliverly_version2.base.BaseConfig;
import com.duora.bobge.duoradeliverly_version2.listener.NavigationPageChangeListener;

import java.util.ArrayList;

/**
 * Created by bobge on 15/8/10.
 */
public class MyViewPager {
    private Activity activity;
    private ViewPager viewPager;
    private LinearLayout mViewPoints;
    private ArrayList<View> pageViews;
    private ImageView imageView;
    /** 将小圆点的图片用数组表示 */
    private ImageView[] imageViews;

    private Handler mHandler = new Handler() {
        @Override
        public void dispatchMessage(Message msg) {
            switch (msg.what) {
                case BaseConfig.MSG_CHANGE_PHOTO:
                    int index = viewPager.getCurrentItem();
                    viewPager.setCurrentItem(index + 1);
                    mHandler.sendEmptyMessageDelayed(BaseConfig.MSG_CHANGE_PHOTO,
                            BaseConfig.PHOTO_CHANGE_TIME);
                    break;
            }
            super.dispatchMessage(msg);
        }
    };

    public MyViewPager(Activity activity) {
        this.activity = activity;
        findViewById(activity);
        addData();
        initPoint();
    }

    private void addData() {
        pageViews = new ArrayList<View>();
        for (int i = 0; i < 5; i++) {
            ImageView imageView = new ImageView(activity);
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            //picasso载入图片
            switch (i){
                case 0:
                    imageView.setBackgroundResource(R.mipmap.a);
                    break;
                case 1:
                    imageView.setBackgroundResource(R.mipmap.b);
                    break;
                case 2:
                    imageView.setBackgroundResource(R.mipmap.c);
                    break;
                case 3:
                    imageView.setBackgroundResource(R.mipmap.e);
                    break;
                case 4:
                    imageView.setBackgroundResource(R.mipmap.f);
                    break;
            }
            pageViews.add(imageView);
        }
    }


    private void findViewById(Activity activity) {
        this.viewPager= (ViewPager)activity.findViewById(R.id.viewPager_main);
        this.mViewPoints= (LinearLayout)activity.findViewById(R.id.viewGroup);
    }

    //创建viewpager的那几个滑动的点
    private void initPoint() {
        // 创建imageviews数组，大小是要显示的图片的数量
        imageViews = new ImageView[pageViews.size()];
        // 加入小圆点的图片
        for (int i = 0; i < pageViews.size(); i++) {
            imageView = new ImageView(activity);
            // 设置小圆点imageview的參数
            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                    20, 20);
            layoutParams.setMargins(5, 0, 5, 0);
            imageView.setLayoutParams(layoutParams);// 创建一个宽高均为20 的布局
            // 将小圆点layout加入到数组中
            imageViews[i] = imageView;
            // 默认选中的是第一张图片，此时第一个小圆点是选中状态，其它不是
            if (i == 0) {
                imageViews[i]
                        .setBackgroundResource(R.mipmap.face_float_icon_on);
            } else {
                imageViews[i]
                        .setBackgroundResource(R.mipmap.face_float_icon);
            }

            // 将imageviews加入到小圆点视图组
            mViewPoints.addView(imageViews[i]);
        }
        // 设置viewpager的适配器和监听事件
        Log.i("test", pageViews.size() + "====");
        viewPager.setAdapter(new EventPageAdapter(pageViews));
        viewPager.setOnPageChangeListener(new NavigationPageChangeListener(pageViews, imageViews));
        viewPager.setCurrentItem((pageViews.size()) * 50);
        if(pageViews.size()>1){
            mHandler.sendEmptyMessageDelayed(BaseConfig.MSG_CHANGE_PHOTO, BaseConfig.PHOTO_CHANGE_TIME);
        }
    }
}

它的滑动监听和适配器：

NavigationPageChangeListener.java看命名应该就能知道这个类的作用了，不多说。

package com.duora.bobge.duoradeliverly_version2.listener;

import android.support.v4.view.ViewPager;
import android.view.View;
import android.widget.ImageView;

import com.duora.bobge.duoradeliverly_version2.R;

import java.util.ArrayList;

/**
 * Created by bobge on 15/8/5.
 */
//viewpager滑动监听
public class NavigationPageChangeListener implements ViewPager.OnPageChangeListener {

    private ArrayList<View> pageViews;
    /** 将小圆点的图片用数组表示 */
    private ImageView[] imageViews;
    public NavigationPageChangeListener(ArrayList<View> pageViews, ImageView[] imageViews) {
        this.pageViews=pageViews;
        this.imageViews=imageViews;
    }

    @Override
    public void onPageScrollStateChanged(int arg0) {
    }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) {
    }

    @Override
    public void onPageSelected(int position) {
        //当页面切换时设置导航点的状态
        setPointStatus(position);
    }
    //设置导航点的状态
    private void setPointStatus(int position) {
        position=position%pageViews.size();
        for (int i = 0; i < imageViews.length; i++) {
            imageViews[position]
                    .setBackgroundResource(R.mipmap.face_float_icon_on);
            // 不是当前选中的page。其小圆点设置为未选中的状态
            if (position != i) {
                imageViews[i]
                        .setBackgroundResource(R.mipmap.face_float_icon);
            }
        }
    }

}

EventPagerAdapter.java类是viewpager的适配器。instantiateItem方法做了一些处理。使事实上现无限循环。

package com.duora.bobge.duoradeliverly_version2.adapter;

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;

import java.util.ArrayList;

/**
 * Created by bobge on 15/7/30.
 */
public class EventPageAdapter extends PagerAdapter {
    private ArrayList<View> pageViews;
    public EventPageAdapter(ArrayList<View> pageViews) {
        this.pageViews=pageViews;
    }

    // 销毁position位置的界面
    @Override
    public void destroyItem(View container, int position, Object object) {

        ((ViewPager) container).removeView(pageViews.get(position%pageViews.size()));
    }

    // 获取当前窗口界面数
    @Override
    public int getCount() {
        return Integer.MAX_VALUE;
    }

    // 初始化position位置的界面
    @Override
    public Object instantiateItem(View v, int position) {
        try{
            //((ViewPager) arg0).addView(list.get(arg1),0);
            ((ViewPager) v).addView((View)pageViews.get(position%pageViews.size()),0);
        }catch (Exception e) {
            // TODO: handle exception
        }
        return pageViews.get(position%pageViews.size());
    }

    @Override
    public boolean isViewFromObject(View v, Object arg1) {
        return v == arg1;
    }

    @Override
    public void startUpdate(View arg0) {
    }

    @Override
    public int getItemPosition(Object object) {
        return super.getItemPosition(object);
    }

}

布局：custom_viewpager.xml

<?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">
    <!--带导航点的viewpager布局-->
    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

    <LinearLayout
        android:id="@+id/viewGroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="20dp"
        android:gravity="center_horizontal"
        android:orientation="horizontal" >
    </LinearLayout>
</RelativeLayout>

在activity的布局中仅仅须要导入上面那个布局就可以：

<include
    layout="@layout/custom_viewpager"
    android:id="@+id/myViewPager"
    android:layout_width="match_parent"
    android:layout_height="@dimen/viewpager_height"
    />