假设我有一个以编程方式添加fragment的Activity:privatevoidanimateToFragment(FragmentnewFragment,Stringtag){FragmentTransactionft=getFragmentManager().beginTransaction();ft.replace(R.id.fragment_container,newFragment,tag);ft.addToBackStack(null);ft.commit();}返回上一个可见fragment的最佳方法是什么？我找到了Triggerback-buttonfunction