Android ViewPager加载图片效果
目前项目中需要用到ViewPager加载图片，现在在此记录一下。
首先先看布局文件：activity_main.xml
<?xmlversion="1.0"encoding="utf-8"?> <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"/> </RelativeLayout>
MainActivity
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{
privateViewPagervp;
privateViewPagerAdaptervpAdapter;
privateList<Map<String,Object>>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(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Intentintent=newIntent();
//intent.putStringArrayListExtra("GalleryPlusActivity",ArrayList<String>);//怎么传递集合
ArrayList<String>imageLists=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<String,Object>>getData(ArrayList<String>imageLists){
List<Map<String,Object>>mData=newArrayList<>();
//if(imageLists!=null&&imageLists.size()>0){
//for(inti=0;i<imageLists.size();i++){
//Map<String,Object>map=newHashMap<>();
//map.put("url",imageLists.get(i));
//map.put("view",newImageView(this));
//mData.add(map);
//}
//}
Map<String,Object>map=newHashMap<>();
map.put("url","http://img2.duitang.com/uploads/item/201207/19/20120719132725_UkzCN.jpeg");
map.put("view",newImageView(this));
mData.add(map);
Map<String,Object>map1=newHashMap<>();
map1.put("url","http://img4.duitang.com/uploads/item/201404/24/20140424195028_vtvZu.jpeg");
map1.put("view",newImageView(this));
mData.add(map1);
Map<String,Object>map2=newHashMap<>();
map2.put("url","http://download.pchome.net/wallpaper/pic-5041-8-240x320.jpg");
map2.put("view",newImageView(this));
mData.add(map2);
Map<String,Object>map3=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.LayoutParamsmLayoutParams=newLinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
mLayoutParams.setMargins(3,0,3,0);
LinearLayoutll=(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(Viewv){
intposition=(Integer)v.getTag();
setCurView(position);
setCurDot(position);
}
}
ViewPagerAdapter
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{
Contextcontext;
List<Map<String,Object>>viewLists;
publicViewPagerAdapter(List<Map<String,Object>>lists,Contextcontext){
this.viewLists=lists;
this.context=context;
}
@Override
publicintgetCount(){//获得size
returnviewLists.size();
}
@Override
publicbooleanisViewFromObject(Viewview,Objectobject){
returnview==object;
}
@Override
publicvoiddestroyItem(ViewGroupview,intposition,Objectobject){//销毁Item
ImageViewx=(ImageView)viewLists.get(position).get("view");
x.setScaleType(ImageView.ScaleType.FIT_CENTER);
view.removeView(x);
}
@Override
publicObjectinstantiateItem(ViewGroupview,intposition){//实例化Item
ImageViewimageView=(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");
}
}
是不是很简单。
最后附上demo：http://xiazai.jb51.net/201701/yuanma/ViewPager(jb51.net).rar
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持毛票票。