Android ViewPager加载图片效果

<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"

 xmlns:tools="http://schemas.android.com/tools"

 android:id="@+id/activity_main"

 android:layout_width="match_parent"

 android:layout_height="match_parent"

 tools:context="com.example.fly.viewpagerbanner.MainActivity">

 <android.support.v4.view.ViewPager

  android:id="@+id/viewpager"

  android:layout_above="@+id/ll"

  android:layout_width="fill_parent"

  android:layout_height="fill_parent"/>

 <LinearLayout

  android:id="@+id/ll"

  android:layout_marginTop="10.0dip"

  android:orientation="horizontal"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:layout_marginBottom="24.0dip"

  android:layout_alignParentBottom="true"

  android:layout_centerHorizontal="true"/>

packagecom.example.fly.viewpagerbanner;

importandroid.support.v4.view.ViewPager;

importandroid.support.v7.app.AppCompatActivity;

importandroid.os.Bundle;

importandroid.view.View;

importandroid.widget.ImageView;

importandroid.widget.LinearLayout;

importandroid.widget.Toast;

importjava.util.ArrayList;

importjava.util.HashMap;

importjava.util.List;

importjava.util.Map;

/**

 * 类名：

 * 类描述：ViewPager展示图片

 * 创建人：fly

 * 创建日期： 2017/1/16.

 * 版本：V1.0

 */

publicclassMainActivityextendsAppCompatActivityimplementsViewPager.OnPageChangeListener,View.OnClickListener {

 privateViewPager vp;

 privateViewPagerAdapter vpAdapter;

 privateList<Map> data;

 privateintlastValue = -1;// 是不是最后一张图片

 privateImageView[] dots;//底部小点图片

 privateintcurrentIndex;//记录当前选中位置

 @Override

 protectedvoidonCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);

  //  Intent intent = new Intent();

//  intent.putStringArrayListExtra("GalleryPlusActivity",ArrayList); // 怎么传递集合

  ArrayListimageLists = getIntent().getStringArrayListExtra("GalleryPlusActivity");// 动态获取展示图片的集合

  data = getData(imageLists);

  vp = (ViewPager) findViewById(R.id.viewpager);

  vpAdapter =newViewPagerAdapter(data,this);

  vp.setAdapter(vpAdapter);

  vp.addOnPageChangeListener(this);

  initDots();//初始化底部小点

 }

 //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

 publicList<Map> getData(ArrayListimageLists) {

  List<Map> mData =newArrayList<>();

//  if (imageLists != null && imageLists.size() > 0) {

//   for (int i = 0; i < imageLists.size(); i++) {

//    Mapmap = new HashMap<>();

//    map.put("url", imageLists.get(i));

//    map.put("view", new ImageView(this));

//    mData.add(map);

//   }

//  }

  Mapmap =newHashMap<>();

  map.put("url","http://img2.duitang.com/uploads/item/201207/19/20120719132725_UkzCN.jpeg");

  map.put("view",newImageView(this));

  mData.add(map);

  Mapmap1 =newHashMap<>();

  map1.put("url","http://img4.duitang.com/uploads/item/201404/24/20140424195028_vtvZu.jpeg");

  map1.put("view",newImageView(this));

  mData.add(map1);

  Mapmap2 =newHashMap<>();

  map2.put("url","http://download.pchome.net/wallpaper/pic-5041-8-240x320.jpg");

  map2.put("view",newImageView(this));

  mData.add(map2);

  Mapmap3 =newHashMap<>();

  map3.put("url","http://www.mangowed.com/uploads/allimg/130425/572-130425105311304.jpg");

  map3.put("view",newImageView(this));

  mData.add(map3);

  returnmData;

 }

 privatevoidinitDots() {

  LinearLayout.LayoutParams mLayoutParams =newLinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);

  mLayoutParams.setMargins(3,0,3,0);

  LinearLayout ll = (LinearLayout) findViewById(R.id.ll);

  dots =newImageView[data.size()];

  //循环取得小点图片

  for(inti =0; i < data.size(); i++) {

   dots[i] =newImageView(this);

   dots[i].setLayoutParams(mLayoutParams);

   dots[i].setBackgroundResource(R.drawable.dot);

   dots[i].setEnabled(true);//都设为灰色

   dots[i].setOnClickListener(this);

   dots[i].setTag(i);//设置位置tag，方便取出与当前位置对应

   ll.addView(dots[i]);

  }

  currentIndex =0;

  dots[currentIndex].setEnabled(false);//设置为白色，即选中状态

 }

 privatevoidsetCurView(intposition) {/**设置当前的引导页*/

  if(position<0|| position="">= data.size()) {return;}

  vp.setCurrentItem(position);

 }

 privatevoidsetCurDot(intposition) {/**设置当前引导小点的选中*/

  if(position<0|| position="">data.size() -1|| currentIndex == position) {return;}

  dots[position].setEnabled(false);

  dots[currentIndex].setEnabled(true);

  currentIndex = position;

 }

 @Override//当前页面被滑动时调用

 publicvoidonPageScrolled(intposition,floatpositionOffset,intpositionOffsetPixels) {

  lastValue = position;

 }

 @Override

 publicvoidonPageSelected(intposition) {    //当新的页面被选中时调用

  setCurDot(position);//设置底部小点选中状态

 }

 @Override

 publicvoidonPageScrollStateChanged(intstate) {  //当滑动状态改变时调用

  if(state ==0){

   if(lastValue == data.size()-1){

    Toast.makeText(this,"已经是最后一张了", Toast.LENGTH_SHORT).show();

   }

  }

 }

 @Override

 publicvoidonClick(View v) {

  intposition = (Integer)v.getTag();

  setCurView(position);

  setCurDot(position);

 }

}

packagecom.example.fly.viewpagerbanner;

importandroid.content.Context;

importandroid.support.v4.view.PagerAdapter;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.ImageView;

importcom.bumptech.glide.Glide;

importcom.bumptech.glide.load.engine.DiskCacheStrategy;

importjava.util.List;

importjava.util.Map;

publicclassViewPagerAdapterextendsPagerAdapter {

 Context context;

 List<Map> viewLists;

 publicViewPagerAdapter(List<Map> lists, Context context) {

  this.viewLists = lists;

  this.context = context;

 }

 @Override

 publicintgetCount() { //获得size

  returnviewLists.size();

 }

 @Override

 publicbooleanisViewFromObject(View view, Object object) {

  returnview == object;

 }

 @Override

 publicvoiddestroyItem(ViewGroup view,intposition, Object object) {//销毁Item

  ImageView x = (ImageView) viewLists.get(position).get("view");

  x.setScaleType(ImageView.ScaleType.FIT_CENTER);

  view.removeView(x);

 }

 @Override

 publicObject instantiateItem(ViewGroup view,intposition){//实例化Item

  ImageView imageView = (ImageView) viewLists.get(position).get("view");

  imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);

  Glide.with(context)

    .load(viewLists.get(position).get("url").toString())

//    .placeholder(R.mipmap.new_default)

    .error(R.mipmap.ic_launcher)

    .diskCacheStrategy(DiskCacheStrategy.RESULT)

    .into(imageView);

  view.addView(imageView,0);

  returnviewLists.get(position).get("view");

 }

}