NestedScrollView中的Viewpager不滚动

public class NestedViewPager extends ViewPager {
    private boolean isScrollable = true;

    public NestedViewPager(Context context) {
        super(context);
    }

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

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (isScrollable) {
            try {
                return super.onInterceptTouchEvent(ev);
            } catch (IllegalArgumentException e) {
                e.printStackTrace();
                return false;
            }
        }
        return false;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (isScrollable) {
            return super.onTouchEvent(ev);
        }
        return false;
    }

    public void setScrollable(boolean scrollable) {
        isScrollable = scrollable;
    }
}