209.m1-banner的自动切换

banner的自动切换是利用hanndler，实现延迟执行，无线调用某个延迟执行的方法，实现一直循环执行延迟播放方法，同时，当点击的时候也需要把自动切换关闭，松开以后重新自动打开。需要注意的是ViewPager触摸时间的返回值是false,不拦截事件。

package com.ldw.market.holder;import java.util.LinkedList;import java.util.List;import com.ldw.market.R;import com.ldw.market.http.HttpHelper;import com.ldw.market.utils.UiUtils;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.FrameLayout;import android.view.ViewGroup.LayoutParams;import android.widget.ImageView;public class HomePictureHolder extends BaseHolder<List<String>> {//holder创建的时候调用下面的方法private ViewPager viewPager;private List<String> datas;@Overridepublic View initView() {viewPager=new ViewPager(UiUtils.getContext());//给ViewPager设置布局的参数LayoutParames,宽度设置在res/values/demons.xml中viewPager.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.MATCH_PARENT,UiUtils.getDimens(R.dimen.banner_picture_height)));return viewPager;}//holder中设置数据调用setData的掉用@Overridepublic void refreshView(List<String> datas) {this.datas = datas;viewPager.setAdapter(new HomeAdapter());//当前条目的设置，实现“无限”滑动viewPager.setCurrentItem(1000*datas.size());/*runTask = new AuToRunTask();runTask.start();*///当ViewPager按下的时候取消自动切换viewPager.setOnTouchListener(new OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:runTask.stop();   break;case MotionEvent.ACTION_CANCEL:  // 事件的取消case MotionEvent.ACTION_UP:runTask.start();break;}return false; // viewPager 触摸事件 返回值要是false  }});runTask = new AuToRunTask();runTask.start();}boolean flag;private AuToRunTask runTask;//banner自动切换public class AuToRunTask implements Runnable{@Overridepublic void run() {if(flag){//先取消之前的任务UiUtils.cancel(this);// 获取到ViewPager当前的条目int currentItem = viewPager.getCurrentItem();currentItem ++;viewPager.setCurrentItem(currentItem);// 延迟执行当前的任务UiUtils.postDelayed(this, 3000);}}//开始执行循环public void start(){//如果之前的停止的if(!flag){UiUtils.cancel(this);flag = true;//递归调用UiUtils.postDelayed(this, 3000);}}//停止public  void stop(){if(flag){flag=false;UiUtils.cancel(this);}}}class HomeAdapter extends PagerAdapter{//管理ImageView避免每次都new ImageView().LinkedList增删快速LinkedList<ImageView> convertView = new LinkedList<ImageView>();@Overridepublic int getCount() {// 数目设置到最大，实现循环return Integer.MAX_VALUE;}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0==arg1;}@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {//uper.destroyItem(container, position, object);//移除的对象转化成ImageView对象ImageView view = (ImageView) object;//把移除的对象添加到缓存的集合中convertView.add(view);container.removeView((View)object);}@Overridepublic Object instantiateItem(ViewGroup container, int position) {int index = position%datas.size();ImageView view;//如果缓存的集合不是空的就从集合中获取if(convertView.size() > 0){//获取到集合的第一个元素view = convertView.remove(0);}else{view = new ImageView(UiUtils.getContext());}//初始化imageViewbitmapUtils.display(view, HttpHelper.URL+"image?name="+datas.get(index));container.addView(view);  //加载的view对象return view; // 返回的对象}}}

UiUtils.java

package com.ldw.market.utils;import android.content.Context;import android.content.res.Resources;import android.graphics.drawable.Drawable;import android.view.View;import com.ldw.market.BaseApplication;/* * 工具类，加载字符串 */public class UiUtils {/* * 获取到字符数组 ，加载XML文件中的字符数组 * @param tabNames  字符数组的id */public static String[] getStringArray(int tabNames) {return getResource().getStringArray(tabNames);}public static Resources getResource() {//获取资源return BaseApplication.getApplication().getResources();}public static Context getContext(){//获取到上下文return BaseApplication.getApplication();}/** dip转换px */public static int dip2px(int dip) {final float scale = getResource().getDisplayMetrics().density;return (int) (dip * scale + 0.5f);}/** pxz转换dip */public static int px2dip(int px) {final float scale = getResource().getDisplayMetrics().density;return (int) (px / scale + 0.5f);}//获取到res/values/demons.xml的配置参数public static int getDimens(int homePictureHeight) {return (int) getResource().getDimension(homePictureHeight);}/** * 把Runnable 方法提交到主线程运行 * @param runnable */public static void runOnUiThread(Runnable runnable) {// 在主线程运行if(android.os.Process.myTid()==BaseApplication.getMainTid()){runnable.run();}else{//获取主线程的handler  BaseApplication.getHandler().post(runnable);}}public static View inflate(int id) {return View.inflate(getContext(), id, null);}public static Drawable getDrawalbe(int id) {return getResource().getDrawable(id);}//延迟time时间执行taskpublic static void postDelayed(Runnable run, int time) {// 获取到主线程的handlerBaseApplication.getHandler().postDelayed(run, time);//调用runnable中的run方法}//取消一个任务public static void cancel(Runnable run) {// 获取到主线程的handlerBaseApplication.getHandler().removeCallbacks(run);}}