最近开发中需要做一个类似京东首页那样的广告轮播效果，于是采用ViewPager自己自定义了一个轮播图效果的View。
主要原理就是利用定时任务器定时切换ViewPager的页面。
效果图如下：
主页面布局实现如下：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"> <android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" /> <LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:padding="5dp"
android:gravity="center"
android:orientation="horizontal"> <View
android:id="@+id/v_dot1"
android:layout_width="8dp"
android:layout_height="8dp"
android:background="@drawable/dot_black" /> <View
android:id="@+id/v_dot2"
android:layout_width="8dp"
android:layout_height="8dp"
android:layout_marginLeft="5dp"
android:background="@drawable/dot_white" /> <View
android:id="@+id/v_dot3"
android:layout_width="8dp"
android:layout_height="8dp"
android:layout_marginLeft="5dp"
android:background="@drawable/dot_white" /> <View
android:id="@+id/v_dot4"
android:layout_width="8dp"
android:layout_height="8dp"
android:layout_marginLeft="5dp"
android:background="@drawable/dot_white" /> <View
android:id="@+id/v_dot5"
android:layout_width="8dp"
android:layout_height="8dp"
android:layout_marginLeft="5dp"
android:background="@drawable/dot_white" /> </LinearLayout>
</RelativeLayout>
轮播效果视图类代码实现如下：
package com.czm.customview; import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit; import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType; /**
* ViewPager实现的轮播图广告自定义视图，如京东首页的广告轮播图效果；
* 既支持自动轮播页面也支持手势滑动切换页面
* @author caizhiming
*
*/ public class SlideShowView extends FrameLayout { //轮播图图片数量
private final static int IMAGE_COUNT = 5;
//自动轮播的时间间隔
private final static int TIME_INTERVAL = 5;
//自动轮播启用开关
private final static boolean isAutoPlay = true; //自定义轮播图的资源ID
private int[] imagesResIds;
//放轮播图片的ImageView 的list
private List<ImageView> imageViewsList;
//放圆点的View的list
private List<View> dotViewsList; private ViewPager viewPager;
//当前轮播页
private int currentItem = 0;
//定时任务
private ScheduledExecutorService scheduledExecutorService;
//Handler
private Handler handler = new Handler(){ @Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
viewPager.setCurrentItem(currentItem);
} }; public SlideShowView(Context context) {
this(context,null);
// TODO Auto-generated constructor stub
}
public SlideShowView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
// TODO Auto-generated constructor stub
}
public SlideShowView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
initData();
initUI(context);
if(isAutoPlay){
startPlay();
} }
/**
* 开始轮播图切换
*/
private void startPlay(){
scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
scheduledExecutorService.scheduleAtFixedRate(new SlideShowTask(), 1, 4, TimeUnit.SECONDS);
}
/**
* 停止轮播图切换
*/
private void stopPlay(){
scheduledExecutorService.shutdown();
}
/**
* 初始化相关Data
*/
private void initData(){
imagesResIds = new int[]{
R.drawable.pic1,
R.drawable.pic2,
R.drawable.pic3,
R.drawable.pic4,
R.drawable.pic5, };
imageViewsList = new ArrayList<ImageView>();
dotViewsList = new ArrayList<View>(); }
/**
* 初始化Views等UI
*/
private void initUI(Context context){
LayoutInflater.from(context).inflate(R.layout.layout_slideshow, this, true);
for(int imageID : imagesResIds){
ImageView view = new ImageView(context);
view.setImageResource(imageID);
view.setScaleType(ScaleType.FIT_XY);
imageViewsList.add(view);
}
dotViewsList.add(findViewById(R.id.v_dot1));
dotViewsList.add(findViewById(R.id.v_dot2));
dotViewsList.add(findViewById(R.id.v_dot3));
dotViewsList.add(findViewById(R.id.v_dot4));
dotViewsList.add(findViewById(R.id.v_dot5)); viewPager = (ViewPager) findViewById(R.id.viewPager);
viewPager.setFocusable(true); viewPager.setAdapter(new MyPagerAdapter());
viewPager.setOnPageChangeListener(new MyPageChangeListener());
} /**
* 填充ViewPager的页面适配器
* @author caizhiming
*/
private class MyPagerAdapter extends PagerAdapter{ @Override
public void destroyItem(View container, int position, Object object) {
// TODO Auto-generated method stub
//((ViewPag.er)container).removeView((View)object);
((ViewPager)container).removeView(imageViewsList.get(position));
} @Override
public Object instantiateItem(View container, int position) {
// TODO Auto-generated method stub
((ViewPager)container).addView(imageViewsList.get(position));
return imageViewsList.get(position);
} @Override
public int getCount() {
// TODO Auto-generated method stub
return imageViewsList.size();
} @Override
public boolean isViewFromObject(View arg0, Object arg1) {
// TODO Auto-generated method stub
return arg0 == arg1;
}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
// TODO Auto-generated method stub } @Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
} @Override
public void startUpdate(View arg0) {
// TODO Auto-generated method stub } @Override
public void finishUpdate(View arg0) {
// TODO Auto-generated method stub } }
/**
* ViewPager的监听器
* 当ViewPager中页面的状态发生改变时调用
* @author caizhiming
*/
private class MyPageChangeListener implements OnPageChangeListener{ boolean isAutoPlay = false; @Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
switch (arg0) {
case 1:// 手势滑动，空闲中
isAutoPlay = false;
break;
case 2:// 界面切换中
isAutoPlay = true;
break;
case 0:// 滑动结束，即切换完毕或者加载完毕
// 当前为最后一张，此时从右向左滑，则切换到第一张
if (viewPager.getCurrentItem() == viewPager.getAdapter().getCount() - 1 && !isAutoPlay) {
viewPager.setCurrentItem(0);
}
// 当前为第一张，此时从左向右滑，则切换到最后一张
else if (viewPager.getCurrentItem() == 0 && !isAutoPlay) {
viewPager.setCurrentItem(viewPager.getAdapter().getCount() - 1);
}
break;
}
} @Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub } @Override
public void onPageSelected(int pos) {
// TODO Auto-generated method stub currentItem = pos;
for(int i=0;i < dotViewsList.size();i++){
if(i == pos){
((View)dotViewsList.get(pos)).setBackgroundResource(R.drawable.dot_black);
}else {
((View)dotViewsList.get(i)).setBackgroundResource(R.drawable.dot_white);
}
}
} } /**
*执行轮播图切换任务
*@author caizhiming
*/
private class SlideShowTask implements Runnable{ @Override
public void run() {
// TODO Auto-generated method stub
synchronized (viewPager) {
currentItem = (currentItem+1)%imageViewsList.size();
handler.obtainMessage().sendToTarget();
}
} }
/**
* 销毁ImageView资源，回收内存
* @author caizhiming
*/
private void destoryBitmaps() { for (int i = 0; i < IMAGE_COUNT; i++) {
ImageView imageView = imageViewsList.get(i);
Drawable drawable = imageView.getDrawable();
if (drawable != null) {
//解除drawable对view的引用
drawable.setCallback(null);
}
}
} }
如何引用上面自定义的轮播图效果视图View呢？其实很引用普通的View类似，实现如下：
<com.czm.customview.SlideShowView
android:id="@+id/slideshowView"
android:layout_width="335dp"
android:layout_height="120dp"
android:layout_centerHorizontal="true"
/>