本文实例讲述了Android开发实现广告无限循环功能。分享给大家供大家参考，具体如下：
一、效果图：
二、代码实现：
public class NewsHomeFragment extends baseFragment implements onTouchListener {
private ImageHandler mHandler = new ImageHandler(new WeakReference(this));
private ViewPager mViewPager;
// 自定义轮播图的资源
private int[] mImageResIds = { R.drawable.img1, R.drawable.img2, R.drawable.img3, R.drawable.img4, R.drawable.img5 };
// 放轮播图片的ImageView 的list
private List mImageList = new ArrayList();
// 放圆点的View的list
private List mDotList = new ArrayList();
@Override
public View initConvertView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_news_main, container, false);
}
@Override
protected void onVisible(boolean isInit) {
if (isInit) {
initViews();
}
}
private void initViews() {
// 初始化iewPager的内容
mViewPager = (ViewPager) mConvertView.findViewById(R.id.view_pager);
LinearLayout dotLayout = (LinearLayout) mConvertView.findViewById(R.id.dotLayout);
dotLayout.removeAllViews();
for (int i = 0; i < mImageResIds.length; i++) {
ImageView imageView = new ImageView(getActivity());
imageView.setScaleType(ScaleType.FIT_XY);
// view.setTag(mImageResId[i]);
imageView.setImageResource(mImageResIds[i]);
mImageList.add(imageView);
View dotView = new View(getActivity());
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(getResources().getDimensionPixelSize(R.dimen.dot_width),
getResources().getDimensionPixelSize(R.dimen.dot_width));
params.setMargins(4, 0, 4, 0);
dotView.setLayoutParams(params);
// if (i == 0) {
//dotView.setBackgroundResource(R.drawable.dot_red);
// } else {
//dotView.setBackgroundResource(R.drawable.dot_gray);
// }
dotLayout.addView(dotView);
mDotList.add(dotView);
}
mViewPager.setAdapter(new ImageAdapter(mImageList));
mViewPager.setonPageChangeListener(new PageChangeListener());
mViewPager.setFocusable(true);
mViewPager.setCurrentItem(Integer.MAX_VALUE / 2);// 默认在中间，使用户看不到边界
mViewPager.setonTouchListener(this);
// 开始轮播效果
mHandler.sendEmptyMessageDelayed(ImageHandler.MSG_UPDATe_IMAGE, ImageHandler.MSG_DELAY);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mHandler.sendEmptyMessage(ImageHandler.MSG_KEEP_SILENT);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mHandler.sendEmptyMessageDelayed(ImageHandler.MSG_UPDATE_IMAGE, ImageHandler.MSG_DELAY);
break;
}
return false;
}
private class PageChangeListener implements onPageChangeListener {
// 配合Adapter的currentItem字段进行设置。
@Override
public void onPageSelected(int position) {
// 这个是设置左滑切换底部view的边界，必须要设置
App.getInstance().setBorderViewPosition(position);
mHandler.sendMessage(Message.obtain(mHandler, ImageHandler.MSG_PAGE_CHANGED, position, 0));
}
@Override
public void onPageScrolled(int position, float arg1, int arg2) {
}
// 覆写该方法实现轮播效果的暂停和恢复
@Override
public void onPageScrollStateChanged(int state) {
switch (state) {
case ViewPager.SCROLL_STATE_DRAGGING:
mHandler.sendEmptyMessage(ImageHandler.MSG_KEEP_SILENT);
break;
case ViewPager.SCROLL_STATE_IDLE:
mHandler.sendEmptyMessageDelayed(ImageHandler.MSG_UPDATE_IMAGE, ImageHandler.MSG_DELAY);
break;
default:
break;
}
}
}
private class ImageAdapter extends PagerAdapter {
private List viewlist;
public ImageAdapter(List viewlist) {
this.viewlist = viewlist;
}
@Override
public int getCount() {
// 设置成最大，使用户看不到边界
return Integer.MAX_VALUE;
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
// Warning：不要在这里调用removeView
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
// 对ViewPager页号求模取出View列表中要显示的项
position %= viewlist.size();
if (position < 0) {
position = viewlist.size() + position;
}
ImageView view = viewlist.get(position);
// 如果View已经在之前添加到了一个父组件，则必须先remove，否则会抛出IllegalStateException。
ViewParent vp = view.getParent();
if (vp != null) {
ViewGroup parent = (ViewGroup) vp;
parent.removeView(view);
}
container.addView(view);
// 此处可添加监听事件
return view;
}
}
private static class ImageHandler extends Handler {
protected static final int MSG_UPDATE_IMAGE = 1;
protected static final int MSG_KEEP_SILENT = 2;
protected static final int MSG_BREAK_SILENT = 3;
protected static final int MSG_PAGE_CHANGED = 4;
// 轮播间隔时间
protected static final long MSG_DELAY = 3000;
// 使用弱引用避免Handler泄露.这里的泛型参数可以不是Activity，也可以是Fragment等
private WeakReference weakReference;
private int currentItem = 0;
// private boolean isonce = true;
protected ImageHandler(WeakReference wk) {
weakReference = wk;
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
final NewsHomeFragment fragment = weakReference.get();
if (fragment == null) {
// Activity已经回收，无需再处理UI了
return;
}
// 第一次不删重复的消息
if (currentItem != 0) {
// 检查消息队列并移除未发送的消息，这主要是避免在复杂环境下消息出现重复等问题。
if (fragment.mHandler.hasMessages(MSG_UPDATE_IMAGE)) {
fragment.mHandler.removeMessages(MSG_UPDATE_IMAGE);
}
}
switch (msg.what) {
case MSG_UPDATE_IMAGE:
currentItem++;
fragment.mViewPager.setCurrentItem(currentItem);
// 准备下次播放
fragment.mHandler.sendEmptyMessageDelayed(MSG_UPDATE_IMAGE, MSG_DELAY);
break;
case MSG_KEEP_SILENT:
// 只要不发送消息就暂停了
break;
case MSG_BREAK_SILENT:
fragment.mHandler.sendEmptyMessageDelayed(MSG_UPDATE_IMAGE, MSG_DELAY);
break;
case MSG_PAGE_CHANGED:
// 记录当前的页号，避免播放的时候页面显示不正确。
int position = msg.arg1;
int lastIndex = 0;
int index = position % fragment.mImageList.size();
for (int i = 0; i < fragment.mDotList.size(); i++) {
fragment.mDotList.get(i).setBackgroundResource(R.drawable.dot_normal);
}
if (fragment.mDotList.get(index)!=null) {
fragment.mDotList.get(index).setBackgroundResource(R.drawable.dot_red);
}
lastIndex = index;
currentItem = position;
break;
default:
break;
}
}
}
}
三、布局
更多关于Android相关内容感兴趣的读者可查看本站专题：《Android视图View技巧总结》、《Android编程之activity操作技巧总结》、《Android布局layout技巧总结》、《Android开发入门与进阶教程》、《Android资源操作技巧汇总》及《Android控件用法总结》
希望本文所述对大家Android程序设计有所帮助。
