扩展ViewFlow避免和ViewPager滑动冲突，同时支持无限循环，并完美和CircleFlowIndicator结合

首先，为了避免滑动冲突，我们要继承ViewFlow，重写onInterceptTouchEvent

 public class MyViewFlow extends ViewFlow {
     private ViewPager mPager;

     public MyViewFlow(Context context, AttributeSet attrs) {
         super(context, attrs);
     }

     public void setViewPager(ViewPager viewPager) {
         mPager = viewPager;
     }

     @Override
     public boolean onInterceptTouchEvent(MotionEvent ev) {
         if (mPager != null)
             switch (ev.getAction()) {
                 case MotionEvent.ACTION_DOWN:
                     mPager.requestDisallowInterceptTouchEvent(true);
                     break;
                 case MotionEvent.ACTION_UP:
                     mPager.requestDisallowInterceptTouchEvent(false);
                     break;
                 case MotionEvent.ACTION_CANCEL:
                     mPager.requestDisallowInterceptTouchEvent(false);
                     break;
                 case MotionEvent.ACTION_MOVE:
                     mPager.requestDisallowInterceptTouchEvent(true);
                     break;
             }
         return super.onInterceptTouchEvent(ev);
     }
 }

调用setViewPager指定viewPager后，滑动便不再冲突

接下来，我们实现无限循环滚动

 public class AdapterBanner extends BaseAdapter {

     private LayoutInflater mInflater;
     private static final int[] ids = { R.drawable.banner, R.drawable.banner, R.drawable.banner, R.drawable.banner};

     public AdapterBanner(Context context) {
         mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     }

     @Override
     public int getCount() {
         //return ids.length;
         return Integer.MAX_VALUE;//返回很大的值使得getView中的position不断增大来实现循环
     }

     @Override
     public Object getItem(int position) {
         return position;
     }

     @Override
     public long getItemId(int position) {
         return position;
     }

     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
         if (convertView == null) {
             convertView = mInflater.inflate(R.layout.item_fr_acmain_nearby_banner, null);
         }
         convertView.findViewById(R.id.imgView).setBackgroundResource(ids[position%ids.length]);
         return convertView;
     }

 }

关键代码在第13行和31行的红色部分。不过这样实现之后，和CircleFlowIndicator结合使用，会发现程序ANR（无响应），原因是CircleFlowIndicator会调用ViewFlow.getViewCount()来绘制圆点，显然这个数是Integer.MAX_VALUE,圆点数太多了导致ANR，我们需要继续扩展MyViewFlow的getViewCount()。如下。

     private int mCount;
     public void setCount(int count){
         mCount=count;
     }
     @Override
     public int getViewsCount() {
         return mCount;
     }

需要调用MyViewFlow.setCount(int count)指定真实的数目，这样做了之后，发现程序不会ANR了。CircleFlowIndicator绘制的圆点数目也正常。但是会发现，无论怎么滑动，圆点状态都不变化，分析ViewFlow的源码，发现要重写一下onScrollChanged，我们继续扩展MyViewFlow,代码如下。

     private int mLastIndex;
     @Override
     public void setAdapter(Adapter adapter, int initialPosition){
         super.setAdapter(adapter,initialPosition);
         mLastIndex = initialPosition;
     }

     @Override
     protected void onScrollChanged(int h, int v, int oldh, int oldv) {
         //super.onScrollChanged(h, v, oldh, oldv);
         if (mIndicator != null) {
             /*
              * The actual horizontal scroll origin does typically not match the
              * perceived one. Therefore, we need to calculate the perceived
              * horizontal scroll origin here, since we use a view buffer.
              */
             int hPerceived = h + (mCurrentAdapterIndex%mCount - mCurrentBufferIndex)
                     * getChildWidth();

             if(mLastIndex%mCount==mCount-1 && mCurrentAdapterIndex>mLastIndex) {
                 oldh=0;
                 hPerceived = 0;
             }
             if(mLastIndex%mCount==0&&mCurrentAdapterIndex<mLastIndex)
                 hPerceived=h+(mCount-1-mCurrentBufferIndex)*getChildWidth();

             LogUtil.e(Config.MYTAG,"mCurrentAdapterIndex="+mCurrentAdapterIndex);
             LogUtil.e(Config.MYTAG,"mLastIndex="+mLastIndex);
             LogUtil.e(Config.MYTAG, "hPerceived=" + hPerceived);

             mIndicator.onScrolled(hPerceived, v, oldh, oldv);

             mLastIndex=mCurrentAdapterIndex;
         }
     } 

当然，有几个变量mIndicator,mCurrentAdapterIndex，mCurrentBufferIndex是沿用父类ViewFlow的，如果找不到，需要将父类ViewFlow中这些变量改为public即可（虽然从oop角度，这种做法很脏，但很省事，大半夜码文字很累，我很懒）。

至此，大功告成！

整体MyViewFlow代码如下：

package common.control.viewflow;

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.Adapter;

import com.xxx.android.main.Config;

import common.util.LogUtil;

public class MyViewFlow extends ViewFlow {
    private ViewPager mPager;

    public MyViewFlow(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setViewPager(ViewPager viewPager) {
        mPager = viewPager;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (mPager != null)
            switch (ev.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    mPager.requestDisallowInterceptTouchEvent(true);
                    break;
                case MotionEvent.ACTION_UP:
                    mPager.requestDisallowInterceptTouchEvent(false);
                    break;
                case MotionEvent.ACTION_CANCEL:
                    mPager.requestDisallowInterceptTouchEvent(false);
                    break;
                case MotionEvent.ACTION_MOVE:
                    mPager.requestDisallowInterceptTouchEvent(true);
                    break;
            }
        return super.onInterceptTouchEvent(ev);
    }
    private int mCount;
    public void setCount(int count){
        mCount=count;
    }
    @Override
    public int getViewsCount() {
        return mCount;
    }
    private int mLastIndex;
    @Override
    public void setAdapter(Adapter adapter, int initialPosition){
        super.setAdapter(adapter,initialPosition);
        mLastIndex = initialPosition;
    }

    @Override
    protected void onScrollChanged(int h, int v, int oldh, int oldv) {
        //super.onScrollChanged(h, v, oldh, oldv);
        if (mIndicator != null) {
            /*
             * The actual horizontal scroll origin does typically not match the
             * perceived one. Therefore, we need to calculate the perceived
             * horizontal scroll origin here, since we use a view buffer.
             */
            int hPerceived = h + (mCurrentAdapterIndex%mCount - mCurrentBufferIndex)
                    * getChildWidth();

            if(mLastIndex%mCount==mCount-1 && mCurrentAdapterIndex>mLastIndex) {
                oldh=0;
                hPerceived = 0;
            }
            if(mLastIndex%mCount==0&&mCurrentAdapterIndex<mLastIndex)
                hPerceived=h+(mCount-1-mCurrentBufferIndex)*getChildWidth();

            LogUtil.e(Config.MYTAG,"mCurrentAdapterIndex="+mCurrentAdapterIndex);
            LogUtil.e(Config.MYTAG,"mLastIndex="+mLastIndex);
            LogUtil.e(Config.MYTAG, "hPerceived=" + hPerceived);

            mIndicator.onScrolled(hPerceived, v, oldh, oldv);

            mLastIndex=mCurrentAdapterIndex;
        }
    }
}

自动播放就不用讲了，网上很多。同学们如果有收获，记得回赞。