解决 ScrollView 中嵌套 ViewPager 的滑动冲突问题。

SelfishViewPager.java

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

public class SelfishViewPager extends ViewPager {
    int mScaledTouchSlop = 0;
    public SelfishViewPager(Context context) {
        super(context);
    }

    public SelfishViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        mScaledTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    private int downX;
    private boolean isSelfish = false;

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                isSelfish = false;
                downX = (int) ev.getX();
                break;
            case MotionEvent.ACTION_MOVE:
                if (!isSelfish && ev.getX() - downX > mScaledTouchSlop) {
                    requestParentDisallowInterceptTouchEvent();
                    isSelfish = true;
                    if (mSelfishListener != null) {
                        mSelfishListener.onSelfished();
                    }
                }
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                isSelfish = false;
                break;
        }
        return super.dispatchTouchEvent(ev);
    }

    private void requestParentDisallowInterceptTouchEvent() {
        if (getParent() != null) {
            getParent().requestDisallowInterceptTouchEvent(true);
        }
    }

    public interface SelfishListener {
        void onSelfished();
    }

    private SelfishListener mSelfishListener;

    public void setSelfishListener(SelfishListener listener) {
        mSelfishListener = listener;
    }