android应用app离不开服务器端的数据，，我们装在手机上的app应用都是通过http相关协议及方法从对应的服务器上取下来的。几乎所有的app都少不了从网络加载图片并展示在手机上，今天我写的就是把网络图片加载到本地并用ViewPager展示出来，可以实现图片自动滚动播放，当然可以手动翻页。借助了网络图片开源框架ImageLoader，其在github开源地址是：https://github.com/nostra13/Android-Universal-Image-Loader，如果想知道这开源框架的具体使用方法可以参考这篇博客。
下面直接贴代码：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#fff0f0ed" android:orientation="vertical" >
<android.support.v4.view.AutoScrollViewPager android:id="@+id/advertisementVp" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="#ffa1a1a1" /> <LinearLayout android:id="@+id/advertisement_dotLl" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:gravity="center" android:orientation="horizontal" android:paddingBottom="4.5dp" android:paddingTop="4.5dp" > </LinearLayout></RelativeLayout><!–实际项目布局不是这样，这只是个举例–>
下面这个类是我们在实际项目中把V4包中的AutoScrollViewPager做了修改：
public class AutoScrollViewPager<T extends PagerData> extends ViewPager {public interface OnPageItemClickListener<T extends PagerData> {void onPageItemClickListener(T pd);}private int mScrollTime = 0;private int oldIndex = 0;private int curIndex = 0;private List<T> mPagerData = new ArrayList<T>();private PagerAdapter pagerAdapter;private LinearLayout indicatorView;private int focusedDrawable, normalDrawable;private LayoutInflater inflater;private OnPageItemClickListener<T> pageItemClickListener;private boolean isFakeCycle = false;// 是否是假的循环private boolean isStartScroll;public AutoScrollViewPager(Context context, AttributeSet attrs) {super(context, attrs);inflater = LayoutInflater.from(context);focusedDrawable = R.drawable.common_dot_selected;normalDrawable = R.drawable.common_dot_normal;setInternalPageChangeListener(new OnPageChangeListener() {public void onPageSelected(int i) {if (mPagerData.isEmpty() || indicatorView == null || indicatorView.getChildCount() == 0)return;curIndex = i % mPagerData.size();// 取消圆点选中indicatorView.getChildAt(oldIndex).setBackgroundResource(normalDrawable);// 圆点选中indicatorView.getChildAt(curIndex).setBackgroundResource(focusedDrawable);oldIndex = curIndex;}public void onPageScrolled(int arg0, float arg1, int arg2) {}public void onPageScrollStateChanged(int arg0) {}
});// 设置滑动动画时间 ,如果用默认动画时间可不用 ,反射技术实现new FixedSpeedScroller(getContext()).setDuration(this, 700);pagerAdapter = new MyPagerAdapter();setAdapter(pagerAdapter);setOffscreenPageLimit(2);requestDisallowInterceptTouchEvent(true);options = new DisplayImageOptions.Builder()
.showImageForEmptyUri(R.drawable.index_advert_default) //加载错误默认图片.showImageOnFail(R.drawable.index_advert_default)//加载错误时的默认图片.cacheInMemory(true)// 开启内存缓存.cacheOnDisk(true) // 开启硬盘缓存.resetViewBeforeLoading(false).build());}@Overrideprotected void onAttachedToWindow() {super.onAttachedToWindow();if (isStartScroll) {start(mScrollTime);}}@Overrideprotected void onDetachedFromWindow() {super.onDetachedFromWindow();if (isStartScroll)handler.removeCallbacksAndMessages(null);}/** 构建内部索引父view */private void initInnerIndicator() {indicatorView = new IndicatorView(getContext());indicatorView.setGravity(Gravity.CENTER);indicatorView.setBackgroundColor(0x0fFF00FF);indicatorView.setOrientation(LinearLayout.HORIZONTAL);LayoutParams params = new LayoutParams();params.width = ViewGroup.LayoutParams.MATCH_PARENT;params.height = 40;params.gravity = Gravity.BOTTOM;addView(indicatorView, params);}public void setDatas(List<T> imgUrls, LinearLayout outIndicator, boolean needInnerIndicator, boolean isFakeCycle) {this.isFakeCycle = isFakeCycle;setDatas(imgUrls, outIndicator, needInnerIndicator);}/**重复调用可能会anr*/public void setDatas(List<T> imgUrls, LinearLayout outIndicator, boolean needInnerIndicator) {if (outIndicator != null) {indicatorView = outIndicator;} else if (needInnerIndicator) {initInnerIndicator();}mPagerData.clear();mPagerData.addAll(imgUrls);pagerAdapter.notifyDataSetChanged();}/**重新加载图片数据，刷新vp内容*/public void refreshDatas(List<T> imgUrls, LinearLayout outIndicator, boolean needInnerIndicator, boolean isFakeCycle) {this.isFakeCycle = isFakeCycle;if (outIndicator != null) {indicatorView = outIndicator;} else if (needInnerIndicator) {initInnerIndicator();}mPagerData.clear();mPagerData.addAll(imgUrls);pagerAdapter = new MyPagerAdapter();setAdapter(pagerAdapter);pagerAdapter.notifyDataSetChanged();}@Overridevoid dataSetChanged() {super.dataSetChanged();setUpIndicator();}// 设置圆点private void setUpIndicator() {if (indicatorView != null) {indicatorView.removeAllViews();if (mPagerData.isEmpty()) {indicatorView.setVisibility(View.GONE);return;} else {indicatorView.setVisibility(View.VISIBLE);}for (int i = 0; i < mPagerData.size(); i++) {View v = inflater.inflate(R.layout.auto_scrollpage_dot, indicatorView, false);v.setBackgroundResource(normalDrawable);indicatorView.addView(v);}indicatorView.getChildAt(0).setBackgroundResource(focusedDrawable);}curIndex = oldIndex = 0;if (mPagerData.size() > 1 && isFakeCycle) {setCurrentItem(15 – 15 % mPagerData.size());// 设置选中为中间/图片为和第0张一样} else {setCurrentItem(0);}}/** 获取真实的当前位置 */public int getCurrentPosition() {return curIndex;}/** 获取真实的当前位置的数据 */public T getCurrentData() throws IndexOutOfBoundsException {return mPagerData.get(curIndex);}@Overridepublic boolean onInterceptTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_UP || ev.getAction() == MotionEvent.ACTION_CANCEL) {start();} else {handler.removeCallbacksAndMessages(null);}return super.onInterceptTouchEvent(ev);}@Overridepublic boolean onTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_UP || ev.getAction() == MotionEvent.ACTION_CANCEL) {start();} else {handler.removeCallbacksAndMessages(null);}return super.onTouchEvent(ev);}/** 开始广告滚动 */private void start() {start(mScrollTime);}public void start(int scrollTime) {// handler.removeCallbacksAndMessages(null);mScrollTime = scrollTime;isStartScroll = false;if (mScrollTime > 0 && !mPagerData.isEmpty()) {isStartScroll = true;handler.sendMessageDelayed(handler.obtainMessage(), mScrollTime);}}private Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {handler.removeCallbacksAndMessages(null);if (isFakeCycle) {setCurrentItem(getCurrentItem() + 1);} else {if (getCurrentItem() == mPagerData.size() – 1) {setCurrentItem(0, true);} else {setCurrentItem(getCurrentItem() + 1);}}handler.sendMessageDelayed(handler.obtainMessage(), mScrollTime);};};private DisplayImageOptions options;public void setImageOptions(DisplayImageOptions options) {this.options = options;}// 适配器 //循环设置private class MyPagerAdapter extends PagerAdapter {@Overridepublic int getCount() {if (mPagerData.size() == 1) {return 1;} else if (mPagerData.size() > 1) { return isFakeCycle ? Integer.MAX_VALUE : mPagerData.size(); }return 0;}@Overridepublic Object instantiateItem(ViewGroup container, int position) {final int realP = position % mPagerData.size();final ImageView netImgView = (ImageView) inflater.inflate(R.layout.auto_scrollpage_img, container, false);ImageLoader.getInstance().displayImage(mPagerData.get(realP).getImageUrl(), netImgView, options);netImgView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (pageItemClickListener != null) {pageItemClickListener.onPageItemClickListener(mPagerData.get(realP));}}});container.addView(netImgView);return netImgView;}@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {if (object instanceof View) {container.removeView((View) object);}}@Overridepublic boolean isViewFromObject(View view, Object object) {return view == object;}}/** 设置显示条目的点击事件 */public void setOnPageItemClickListener(OnPageItemClickListener<T> pageItemClickListener) {this.pageItemClickListener = pageItemClickListener;}}
是个接口，主要实现取得图片的url:
public interface PagerData{public String getImageUrl();//用于显示网络图片public void setImageUrl(String imgUrl);}
有了以上的准备，只需要在Activity中取得图片的url地址，调用refreshDatas()方法把参数传入就可以了，activity中关键代码：
viewPager = (AutoScrollViewPager<AdvertisementInfo>) headerView.findViewById(R.id.viewPager);//获取ViewPager对象，
advertisementVp.refreshDatas();//传入对应参数 advertisementVp.start(3000);
ok啦，时间原因，没有贴出所有代码，仅供参考。
人生就是要感受美丽的善良的，丑恶的病态的。
