为什么能在子线程通过setText进行更新UI

为什么可以在子线程通过setText进行更新UI void checkThread() { if (mThread != Thread.currentThread()) { throw new CalledFromWrongThreadException( Only the original thread that created a view hierarchy can touch its views.); } } 一般情况下在子线程更新UI是会报错的,因为在ViewRootImpl