import android.app.Activity;import android.content.Context;import android.support.annotation.Nullable;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.util.AttributeSet;import android.util.Log;import android.view.LayoutInflater;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.widget.RelativeLayout;import java.util.ArrayList;import java.util.Date;import java.util.Timer;import java.util.TimerTask;public class Carousel extends RelativeLayout {    private CarouselPager mPager;    private Context mContext;    private int mResourceId = -1;    private Carousel self;    private CarouselDelegate mDelegate;    private CarouselAdapter mAdapter;    private int mCurrentItem = 1;    private int mItemCount;    public Carousel(Context context) {        super(context);        init(context);    }    public Carousel(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        init(context);    }    public Carousel(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context);    }    private void init(Context context) {        mContext = context;        self = this;        mAdapter = new CarouselAdapter();        mPager = new CarouselPager(mContext);        RelativeLayout.LayoutParams layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT);        addView(mPager,layoutParams);        mPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {            @Override            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            }            @Override            public void onPageSelected(int position) {//                Log.d("Selected", "onPageSelected: " + position);                mCurrentItem = position;                int display_index = mCurrentItem;                if (position == 0) {                    display_index = mItemCount;                } else if (position == mItemCount + 1) {                    display_index = 1;                } else {                    display_index = position;                    // 代理方法在此调用避免两端点的索引重复出现                    if (mDelegate != null) {                        mDelegate.carouselDidShowItem(self,display_index - 1);                    }                }            }            @Override            public void onPageScrollStateChanged(int state) {                // 解决两端切换时闪屏                if (state == ViewPager.SCROLL_STATE_IDLE) {                    if (mCurrentItem == mPager.getAdapter().getCount() - 1) {                        mPager.setCurrentItem(1, false);                    }                    else if (mCurrentItem == 0) {                        mPager.setCurrentItem(mPager.getAdapter().getCount() - 2, false);                    }                }            }        });        mPager.setAdapter(mAdapter);        reloadData();    }    public void registResourceId(int resourceId) {        mResourceId = resourceId;    }    public void setDelegate(CarouselDelegate delegate) {        mDelegate = delegate;    }    public void reloadData() {        mAdapter.notifyDataSetChanged();        mCurrentItem = 1;        mPager.setCurrentItem(mCurrentItem,false);        if (mAutoScroll) {            startAutoScroll();        }    }    public interface CarouselDelegate {        void carouselWillShowItem(Carousel carousel,View cell,int index);        void carouselDidShowItem(Carousel carousel,int index);        int  carouselNumberOfItems(Carousel carousel);    }    public class CarouselAdapter extends PagerAdapter {        ArrayList
     
       mReusePool = new ArrayList<>();        @Override        public int getCount() {            if (mDelegate == null || mResourceId == -1) {                return mItemCount = 0;            } else {                int number = mDelegate.carouselNumberOfItems(self);                if (number == 0) {                    return mItemCount = 0;                } else {                    mItemCount = number;                    return number + 2;                }            }        }        @Override        public boolean isViewFromObject(View view, Object object) {            return view == object;        }        @Override        public int getItemPosition(Object object) {//            return super.getItemPosition(object);            return POSITION_NONE; // 解决notifyDataChange后界面没更新        }        @Override        public void destroyItem(ViewGroup container, int position, Object object) {            View cell = (View) object;            container.removeView(cell);            mReusePool.add(cell);        }        @Override        public Object instantiateItem(ViewGroup container, int position) {            View cell = null;            if (mReusePool.isEmpty()) {                cell = (View) LayoutInflater.from(mContext).inflate(mResourceId,null);            } else {                cell = mReusePool.get(0);                mReusePool.remove(cell);            }            int index = position;            if (position == 0) {                index = mItemCount - 1;            } else if (position == mItemCount + 1) {                index = 0;            } else {                index = position - 1;            }            if (mDelegate!= null) {                mDelegate.carouselWillShowItem(self,cell,index);            }            container.addView(cell);            return cell;        }    }    private Timer mTimer;    private TimerTask mTimerTask;    private boolean mAutoScroll = false;    private int mAutoScrollFlag = 0; // Timer开始第一次执行无效    private int mScrollTimeInterval = 10; // 单位秒    public void setAutoScroll(boolean autoScroll) {        mAutoScroll = autoScroll;        if (mAutoScroll) {            startAutoScroll();        } else {            stopAutoScroll();        }    }    public boolean getAutoScroll() {        return mAutoScroll;    }    public void setScrollTimeInterval(int scrollTimeInterval) {        this.mScrollTimeInterval = scrollTimeInterval;    }    public int getScrollTimeInterval() {        return this.mScrollTimeInterval;    }    private void startAutoScroll() {        if (mItemCount == 0) {            return;        }        stopAutoScroll();        mTimer = new Timer();        mTimerTask = new TimerTask() {            @Override            public void run() {                ((Activity)mContext).runOnUiThread(new Runnable() {                    @Override                    public void run() {                        if (mAutoScrollFlag == 0) {                            mAutoScrollFlag = 1;                        } else {                            mPager.setCurrentItem(mCurrentItem + 1,true);                        }                    }                });            }        };        mTimer.schedule(mTimerTask,new Date(),1000 * mScrollTimeInterval);    }    private void stopAutoScroll() {        if (mTimer != null) {            mTimer.cancel();            mTimer = null;            mTimerTask = null;            mAutoScrollFlag = 0;        }    }    private class CarouselPager extends ViewPager {        public CarouselPager(Context context) {            super(context);        }        public CarouselPager(Context context, AttributeSet attrs) {            super(context, attrs);        }        @Override        public boolean onTouchEvent(MotionEvent event) {            if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) {                stopAutoScroll();            }            if (event.getAction() == MotionEvent.ACTION_CANCEL || event.getAction() == MotionEvent.ACTION_UP) {                if (mAutoScroll) {                    startAutoScroll();                }            }            return super.onTouchEvent(event);        }    }}