通过反射获取控件内部属性

private BannerViewPager；
    public void gettBannerViewPager(){
        try {
            Class c = null;
            try {
                c = Class.forName("com.youth.banner.Banner");//获得Class对象，控件的包名
            } catch (Exception e) {
                e.printStackTrace();
            }

            Field mLayoutField = c.getDeclaredField("viewPager");//根据属性名称，获得类的属性成员Field
            mLayoutField.setAccessible(true);//设置为可访问状态
            BannerViewPager viewPager = null;
            try {
                bannerViewPager = (BannerViewPager) mLayoutField.get(this);//获得该属性对应的对象

                if(viewPager == null){
                    return;
                }
            } catch (IllegalAccessException e) {
                e.printStackTrace();
                return;
            }

        }catch (Exception e) {
            e.printStackTrace();
        }
    }