android使用ViewPager实现图片自动切换

2023-07-31 15:19:04 68

本文实现viewpager图片轮播的功能、左右滑动的时候能够流畅的切换图片、并且没有边界限制

1、activity_main.xml布局

因为我的ViewPager是继承RelativeLayout

2、layout_recommend_item.xml中的布局

ImageView是显示图片TextView用来显示每一个pager的标题

3、MyViewPager类，因为图个方便，把能够实现这个功能否合成一个类、这样用起来比较方便

importandroid.content.Context;
importandroid.graphics.Canvas;
importandroid.graphics.Color;
importandroid.graphics.Paint;
importandroid.os.Handler;
importandroid.os.Message;
importandroid.support.v4.view.PagerAdapter;
importandroid.support.v4.view.ViewPager;
importandroid.util.DisplayMetrics;
importandroid.util.Log;
importandroid.util.TypedValue;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.ImageView;
importandroid.widget.RelativeLayout;
importandroid.widget.TextView;

importjava.util.ArrayList;
importjava.util.List;

publicclassMyViewPagerextendsRelativeLayout{
privatestaticfinalintSTART_SCROLL=1;
privatestaticfinalintSCROLL_NEXT=2;
privatestaticfinalintSHOW_TIME=5000;//显示时间
privateListmDatas=newArrayList<>();//viewpager每一页对应的标题
privateViewPagermPager;
privateContextmContext;
privateintmWidth,mHeight;//viewpager的宽高
privateintmTitleHeight;//标题高度
privateTipViewmTipView;//标题对应的view
//在主ui中更新viewpager，也就是切换图片
privatestaticHandlersHandler=newHandler(){
@Override
publicvoidhandleMessage(Messagemsg){
intw=msg.what;
ViewPagerpager=(ViewPager)msg.obj;
switch(w){
caseSTART_SCROLL:
pager.setCurrentItem(msg.arg1,true);
break;
caseSCROLL_NEXT:
pager.setCurrentItem(msg.arg1,true);
break;
}
}
};

/**
*构造函数
*@paramcontextcontent
*@paramw要显示的viewpager的宽
*@paramh要显示的viewpager的高
*/
publicMyViewPager(Contextcontext,intw,inth){
super(context);
mContext=context;
mWidth=w;
mHeight=h;
initView();//取得数据左边随便取的只是为了看起来有效果
//对viewpager滑动进行监听
mPager.setOnPageChangeListener(newMOnPagerChangeListener());
init();
DisplayMetricsdm=mContext.getResources().getDisplayMetrics();
mTitleHeight=cm_DptoPx(48,dm);
}

/**
*对viewpager控件进行绘制宽高
*/
@Override
protectedvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec){
ViewGroup.LayoutParamsvp=getLayoutParams();
if(vp!=null){
vp.width=mWidth;
vp.height=mHeight;
}
super.onMeasure(widthMeasureSpec,heightMeasureSpec);
}

/**
*把dp转化成px
*/
publicstaticintcm_DptoPx(intdp,DisplayMetricsdis){
return(int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,dp,dis);
}

privatevoidinit(){
getData();
}

privatevoidinitView(){
mPager=newViewPager(mContext);
RelativeLayout.LayoutParamsrp=newRelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.MATCH_PARENT);
addView(mPager,rp);
}

publicvoidgetData(){
for(inti=0;i<4;i++){
mDatas.add(i,"viewpager"+i);
}
sHandler.postDelayed(newRunnable(){
@Override
publicvoidrun(){
stopAnimation();
initTipView();
mPager.setAdapter(newRecommendAdapter());
mPager.setCurrentItem(10000*mDatas.size());
}
},2000);
}

/**
*删除队列中的消息
*/
publicvoidstopAnimation(){
sHandler.removeMessages(START_SCROLL);
sHandler.removeMessages(SCROLL_NEXT);
}
publicvoidstartAnimation(){
if(mDatas.size()==0){
return;
}
Messagemsg=sHandler.obtainMessage(START_SCROLL);
msg.obj=mPager;
msg.arg1=(mPager.getCurrentItem()+1);//取得后一张图片
sHandler.sendMessageDelayed(msg,SHOW_TIME);//5秒后发送给ui线程
}

/**
*对标题view移动的光标初始化
*/
privatevoidinitTipView(){

if(mTipView==null){
RelativeLayout.LayoutParamsrp=newRelativeLayout.LayoutParams(10,10);
rp.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
rp.bottomMargin=mTitleHeight;
mTipView=newTipView(mContext,mDatas.size());
addView(mTipView,rp);
}else{
mTipView.setCount(mDatas.size());
}
}



privateclassMOnPagerChangeListenerimplementsViewPager.OnPageChangeListener{
privateintcurState;
@Override
publicvoidonPageScrolled(inti,floatv,inti1){
}
@Override
publicvoidonPageSelected(inti){//滑动结束
sHandler.removeMessages(SCROLL_NEXT);
sHandler.removeMessages(START_SCROLL);
if(curState==ViewPager.SCROLL_STATE_DRAGGING){
return;
}
Messagemsg=sHandler.obtainMessage(SCROLL_NEXT);
msg.arg1=i+1;
msg.obj=mPager;
sHandler.sendMessageDelayed(msg,SHOW_TIME);
mTipView.setCurPostion(i%mDatas.size());
}

@Override
publicvoidonPageScrollStateChanged(inti){//正在滑动时
curState=i;
if(i==ViewPager.SCROLL_STATE_DRAGGING){//SCROLL_STATE_DRAGGING正在滑动SCROLL_STATE_IDLE什么都没有做
//SCROLL_STATE_SETTLING滑动完毕
stopAnimation();
}else{
if(!(sHandler.hasMessages(START_SCROLL)&&sHandler.hasMessages(SCROLL_NEXT))){
startAnimation();
}
}
}
}

privateclassRecommendAdapterextendsPagerAdapter{
@Override
publicObjectinstantiateItem(ViewGroupcontainer,intposition){
Log.i("MyViewPager","instantiateItem");
intcurPos=position%mDatas.size();
Viewview=View.inflate(mContext,R.layout.layout_recommend_item,null);
ViewGroup.LayoutParamsvp=newViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT);
ImageViewiv=(ImageView)view.findViewById(R.id.iv_pic);
TextViewtv=(TextView)view.findViewById(R.id.tv_desc);
tv.setText(mDatas.get(curPos));
container.addView(view,vp);
view.setTag(curPos);
view.setOnClickListener(newOnClickListener(){
@Override
publicvoidonClick(Viewv){
}
});
returnview;
}

@Override
publicintgetCount(){
returnInteger.MAX_VALUE;
}

@Override
publicbooleanisViewFromObject(Viewview,Objecto){
returnview==o;
}

@Override
publicvoiddestroyItem(ViewGroupcontainer,intposition,Objectobject){
container.removeView((View)object);
}
}

privateclassTipViewextendsView{

privateintmPadding;
privateintmCount;
privateintmCurPos;
privatePaintmNorPaint;
privatePaintmSelPaint;
privateintmHeight;

publicTipView(Contextcontext,intcount){
super(context);
mNorPaint=newPaint();
mNorPaint.setAntiAlias(true);
DisplayMetricsdm=context.getResources().getDisplayMetrics();
intselHeight=cm_DptoPx(2,dm);
intnorHeight=cm_DptoPx(1,dm);
mHeight=cm_DptoPx(2,dm);
mNorPaint.setStrokeWidth(norHeight);
mNorPaint.setColor(Color.argb(80,255,255,255));
mSelPaint=newPaint();
mSelPaint.setAntiAlias(true);
mSelPaint.setStrokeWidth(selHeight);
mSelPaint.setColor(Color.WHITE);
mCount=count;
mPadding=cm_DptoPx(0,dm);
}
@Override
protectedvoidonDraw(Canvascanvas){
super.onDraw(canvas);
intow=(getWidth()-2*mPadding)/mCount;
inty=getHeight()/2;
canvas.drawLine(mPadding,y,mCurPos*ow+mPadding,y,mNorPaint);
canvas.drawLine(mCurPos*ow+mPadding,y,(mCurPos+1)*ow+mPadding,y,mSelPaint);
canvas.drawLine((mCurPos+1)*ow+mPadding,y,getWidth()-mPadding,y,mNorPaint);
}
@Override
protectedvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec){
ViewGroup.LayoutParamsvp=getLayoutParams();
vp.width=ViewGroup.LayoutParams.MATCH_PARENT;
vp.height=mHeight;
super.onMeasure(widthMeasureSpec,heightMeasureSpec);
}

publicvoidsetCurPostion(intpos){
mCurPos=pos;
invalidate();
}

publicvoidsetCount(intcount){
mCount=count;
}
}
}

4、还有MainActivity中的实现

importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.util.DisplayMetrics;
importandroid.widget.RelativeLayout;

publicclassMainActivityextendsActivity{
privateRelativeLayoutmViewPager;
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DisplayMetricsdm=getResources().getDisplayMetrics();
mViewPager=(RelativeLayout)findViewById(R.id.my_viewpager);
mViewPager.addView(newMyViewPager(getApplicationContext(),dm.widthPixels,(dm.widthPixels)/2));
}
}

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。

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android使用ViewPager实现图片自动切换

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