Android ViewPager实现图片轮翻效果
很多App都有这种效果，特别一些电商类的App，顶部每隔几秒钟会向右翻页显示下张图片，用来作推广或者内容展示用的。今天来简单地模仿一下，还自带一个自动跳动的小功能（底部有几个小点，图片移动的时候，点的状态也在变化），用定时器来实现不难。
importjava.util.ArrayList;
importjava.util.List;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.os.Handler;
importandroid.os.Message;
importandroid.os.SystemClock;
importandroid.support.v4.view.PagerAdapter;
importandroid.support.v4.view.ViewPager;
importandroid.support.v4.view.ViewPager.OnPageChangeListener;
importandroid.util.Log;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.ImageView;
importandroid.widget.LinearLayout;
importandroid.widget.LinearLayout.LayoutParams;
importandroid.widget.TextView;
publicclassMainActivityextendsActivityimplementsOnPageChangeListener{
protectedstaticfinalStringTAG="MainActivity";
privateList<ImageView>imageViewList;
privateViewPagermViewPager;
privatefinalint[]imageResIDs={
R.drawable.a,
R.drawable.b,
R.drawable.c,
R.drawable.d,
R.drawable.e
};
privatefinalString[]imageDescriptions={
"巩俐不低俗，我就不能低俗",
"扑树又回来啦！再唱经典老歌引万人大合唱",
"揭秘北京电影如何升级",
"乐视网TV版大派送",
"热血屌丝的反杀"
};
privateTextViewtvImageDescription;//图片描述
privateLinearLayoutllPointGroup;//点控件的组
privateintpreviousPosition=0;//viewpager选中的前一个position
privatebooleanisStop=false;//控制循环的子线程是否停止
privateHandlerhandler=newHandler(){
@Override
publicvoidhandleMessage(Messagemsg){
super.handleMessage(msg);
mViewPager.setCurrentItem(mViewPager.getCurrentItem()+1);
}
};
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
newThread(newRunnable(){
@Override
publicvoidrun(){
//每两秒钟向主线程发送一条消息,切换viewpager的界面
while(!isStop){
SystemClock.sleep(2000);
handler.sendEmptyMessage(0);
}
Log.i(TAG,"循环线程停止了");
}}).start();
}
@Override
protectedvoidonDestroy(){
isStop=true;
super.onDestroy();
}
privatevoidinitView(){
mViewPager=(ViewPager)findViewById(R.id.viewpager);
llPointGroup=(LinearLayout)findViewById(R.id.ll_point_group);
tvImageDescription=(TextView)findViewById(R.id.tv_image_description);
imageViewList=newArrayList<ImageView>();
ImageViewiv;
ViewpointView;
LayoutParamsparams;
for(inti=0;i<imageResIDs.length;i++){
iv=newImageView(this);
iv.setBackgroundResource(imageResIDs[i]);
imageViewList.add(iv);
//根据图片添加点
pointView=newView(this);
params=newLayoutParams(5,5);
params.leftMargin=5;
pointView.setLayoutParams(params);
pointView.setEnabled(false);
pointView.setBackgroundResource(R.drawable.point_bg);
llPointGroup.addView(pointView);
}
MyPagerAdaptermAdapter=newMyPagerAdapter();
mViewPager.setAdapter(mAdapter);
mViewPager.setOnPageChangeListener(this);
intitem=(Integer.MAX_VALUE/2)-((Integer.MAX_VALUE/2)%imageViewList.size());
mViewPager.setCurrentItem(item);//设置当前选中的item的position
tvImageDescription.setText(imageDescriptions[previousPosition]);
llPointGroup.getChildAt(previousPosition).setEnabled(true);//第一点被选中
}
classMyPagerAdapterextendsPagerAdapter{
@Override
publicintgetCount(){
returnInteger.MAX_VALUE;
}
/**
*移动的对象和进来的对象如果是同一个就返回true,代表复用view对象
*false使用object对象
*/
@Override
publicbooleanisViewFromObject(Viewarg0,Objectarg1){
returnarg0==arg1;
}
/**
*需要销毁的对象的position传进来
*/
@Override
publicvoiddestroyItem(ViewGroupcontainer,intposition,Objectobject){
//移除掉指定position的对象
mViewPager.removeView(imageViewList.get(position%imageViewList.size()));
}
/**
*加载position位置的view对象
*/
@Override
publicObjectinstantiateItem(ViewGroupcontainer,intposition){
//添加指定position的对象
mViewPager.addView(imageViewList.get(position%imageViewList.size()));
returnimageViewList.get(position%imageViewList.size());
}
}
@Override
publicvoidonPageScrollStateChanged(intarg0){
//TODOAuto-generatedmethodstub
}
@Override
publicvoidonPageScrolled(intarg0,floatarg1,intarg2){
//TODOAuto-generatedmethodstub
}
/**
*当viewpager页面切换时回调
*@paramposition就是当前显示的page页
*/
@Override
publicvoidonPageSelected(intposition){
tvImageDescription.setText(imageDescriptions[position%imageViewList.size()]);
llPointGroup.getChildAt(position%imageViewList.size()).setEnabled(true);
llPointGroup.getChildAt(previousPosition).setEnabled(false);
previousPosition=position%imageViewList.size();
}
}
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。