ViewPager+动态加载网络图片

前言：昨晚上师傅让我写了发给一个人的，因为我很闲，于是就写了，网上我看到好多例子，涉及到好多类，看的头疼还不如自己写，一个类搞定，如下：（PS:防止以后忘记）xml里面就一个ViewPager控件，没啦，哈哈^_^.

package com.yalantis.contextmenu.sample;

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;

import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;
import com.yalantis.contextmenu.R;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class MainActivity2Activity extends ActionBarActivity {
    ViewPager viewPager;
    ViewPagerAdapter adapter;
    List> data;
    protected ImageLoader imageLoader = ImageLoader.getInstance();
    DisplayImageOptions options;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);
        init();
    }

    public void init() {
        viewPager = (ViewPager) findViewById(R.id.mypager);
        data = getData();
        imageLoader=ImageLoader.getInstance();
        imageLoader.init(ImageLoaderConfiguration.createDefault(this));
        options = new DisplayImageOptions.Builder()
                .showStubImage(R.drawable.ic_launcher) // 在ImageView加载过程中显示图片
                .showImageForEmptyUri(R.drawable.ic_launcher) // image连接地址为空时
                .showImageOnFail(R.drawable.ic_launcher) // image加载失败
                .cacheInMemory(true) // 加载图片时会在内存中加载缓存
                .cacheOnDisc(true) // 加载图片时会在磁盘中加载
                .build();
        adapter = new ViewPagerAdapter(data);
        viewPager.setAdapter(adapter);
    }

//这个方法长度是动态的，可以改成你从服务器获取的图片，这样数量就不确定啦
    public List> getData() {
        List> mdata = new ArrayList>();
        Map map = new HashMap();
        map.put("url", "http://img2.duitang.com/uploads/item/201207/19/20120719132725_UkzCN.jpeg");
        map.put("view", new ImageView(this));
        mdata.add(map);

        Map map1 = new HashMap();
        map1.put("url", "http://img4.duitang.com/uploads/item/201404/24/20140424195028_vtvZu.jpeg");
        map1.put("view", new ImageView(this));
        mdata.add(map1);

        Map map2 = new HashMap();
        map2.put("url", "http://download.pchome.net/wallpaper/pic-5041-8-240x320.jpg");
        map2.put("view", new ImageView(this));
        mdata.add(map2);

        Map map3 = new HashMap();
        map3.put("url", "http://www.mangowed.com/uploads/allimg/130425/572-130425105311304.jpg");
        map3.put("view", new ImageView(this));
        mdata.add(map3);
         return  mdata;
    }

    public class ViewPagerAdapter extends PagerAdapter {

        List> viewLists;

        public ViewPagerAdapter(List> lists)
        {
            viewLists = lists;
        }

        @Override
        public int getCount() {                                                                 //获得size
            // TODO Auto-generated method stub
            return viewLists.size();
        }

        @Override
        public boolean isViewFromObject(View arg0, Object arg1) {
            // TODO Auto-generated method stub
            return arg0 == arg1;
        }

        @Override
        public void destroyItem(View view, int position, Object object)                       //销毁Item
        {
            ImageView x=(ImageView)viewLists.get(position).get("view");
            x.setScaleType(ImageView.ScaleType.FIT_CENTER);
            ((ViewPager) view).removeView(x);
        }

        @Override
        public Object instantiateItem(View view, int position)                                //实例化Item
        {
            ImageView x=(ImageView)viewLists.get(position).get("view");
            x.setScaleType(ImageView.ScaleType.FIT_CENTER);
            imageLoader.displayImage(viewLists.get(position).get("url").toString(), x,options);
            ((ViewPager) view).addView(x, 0);

            return viewLists.get(position).get("view");
        }

    }
}