利用Viewpager+Timer实现图片广告轮播

Viewpager实现首页图片广告轮播，早已经满大街都是。今天度娘了一下，可是我发现网上有一些只是单纯的图片轮播，而我想要做到用户点击或者拖拉的时候停止轮播，松开重新等待3秒(间隔的时间自定义)，然后在继续轮播。看了一些帖子有的重写Viewpager也能实现，可是我觉得没必要这么复杂，自己捣鼓了一下。

下面直接上代码：

public class ViewpagerActivity extends AppCompatActivity {private ViewPager viewPager;private int index =0;//记录当前页数private boolean mIsTouching =false ;//判断用户是否接触控件private boolean mIsFirstLeave =false ;//判断是否刚离开控件private int screewidth;//手机屏幕宽度private int screehight;//手机屏幕高度private Timer mTimer;private TimerTask mTimerTask = null;private ArrayList<String> ImgList = new ArrayList<>();private View[] pageViews = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_viewpager);//初始化图片地址ImgList.add("http://b.hiphotos.baidu.com/zhidao/pic/item/0eb30f2442a7d9334907b645ac4bd11373f0015c.jpg");ImgList.add("http://b.hiphotos.baidu.com/zhidao/pic/item/023b5bb5c9ea15ce3793816eb5003af33a87b253.jpg");ImgList.add("http://t1.niutuku.com/960/17/17-434864.jpg");ImgList.add("http://img.51ztzj.com/upload/image/20130424/201304231005_670x419.jpg");ImgList.add("http://cdn.duitang.com/uploads/item/201202/07/20120207094418_YeReK.jpg");/** *这里主要是为了图片自适应宽高，你也可以直接在for循环中 new ImageView  *  **/WindowManager wm = (WindowManager)getSystemService(Context.WINDOW_SERVICE);screewidth = wm.getDefaultDisplay().getWidth();screehight = wm.getDefaultDisplay().getHeight();pageViews = new View[ImgList.size()];LayoutInflater li = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);for (int i = 0; i < ImgList.size(); i++) {pageViews[i] = li.inflate(R.layout.ad_item, null);pageViews[i].setBackgroundDrawable(null);ImageView imageView = (ImageView) pageViews[i].findViewById(R.id.ad_img);ViewGroup.LayoutParams lp = imageView.getLayoutParams();lp.width = screewidth;lp.height = LinearLayout.LayoutParams.WRAP_CONTENT;imageView.setLayoutParams(lp);imageView.setMaxWidth(screewidth);ImageLoader.getInstance().displayImage(ImgList.get(i),imageView);}viewPager = ((ViewPager) findViewById(R.id.vp));viewPager.setOffscreenPageLimit(2);//设置预加载前后2页viewPager.setAdapter(new AdvertisementAdapter(pageViews,this));viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {@Overridepublic void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}@Overridepublic void onPageSelected(int position) {index = viewPager.getCurrentItem() % pageViews.length;//记录当前位置}@Overridepublic void onPageScrollStateChanged(int state) {switch (state) {case ViewPager.SCROLL_STATE_DRAGGING://拖拉的状态mIsTouching  = true;                    mIsFirstLeave =true;stopTimer(); //停止计时器break;case ViewPager.SCROLL_STATE_SETTLING://已加载完毕break;case ViewPager.SCROLL_STATE_IDLE://空闲闲的状态mIsTouching = false;if (mIsFirstLeave){startTimer(); //如果手指刚离开控件开启计时器}break;}}});}private Handler mHandler = new Handler(){@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);switch (msg.what){case 0:viewPager.setCurrentItem(index);break;}}};private void startTimer(){mIsFirstLeave =false;mTimer = new Timer();mTimerTask =new TimerTask() {@Overridepublic void run() {if (index < (pageViews.length - 1)) {index += 1;} else {index = 0;}mHandler.sendEmptyMessage(0);//这里用Handler主要是为了在主线程更新UI}};mTimer.schedule(mTimerTask,3000, 3000);//第一个参数，是 TimerTask 类//第二个参数的意思是第一次执行的时间//第三个参数的意思就是从第二次开始每隔多长的时间调用一次方法。}private void stopTimer(){if (mTimer != null) {mTimer.cancel();mTimer = null;}if (mTimerTask != null) {mTimerTask.cancel();mTimerTask = null;}}}

下面是Adapter:

public class AdvertisementAdapter extends PagerAdapter {private View[] pageViews;private Context context;public AdvertisementAdapter(View[] pageViews,Context context){this.pageViews=pageViews;this.context=context;}@Overridepublic int getCount() {// TODO Auto-generated method stubif(pageViews!=null&&pageViews.length>0){return pageViews.length;}else{return 0;}}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0 == arg1;}public void destroyItem(View container, int position, Object object) {if(pageViews!=null&&pageViews.length>0){((ViewPager)container).removeView(pageViews[position % pageViews.length]);}}/** * 载入当前的position View */@Overridepublic Object instantiateItem(View container, int position) {if(pageViews!=null&&pageViews.length>0){((ViewPager)container).removeView(pageViews[position % pageViews.length]);((ViewPager)container).addView(pageViews[position % pageViews.length], 0);return pageViews[position % pageViews.length];}else{return null;}}}