1。当xml页面中有可见的,同时设置id的控件时,如果在Activity中没有使用注解进行反射该控件,app会crash,提示:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.view.ViewPager.setAdapter(android.support.v4.view.PagerAdapter)' on a null object reference