supportFragmentManager.beginTransaction().replace(R.id.fragment_holder,StartFragment.newInstance()).commit()
} 当这个启动的Fragment返回到时,我想清除整个Fragment后栈。我正尝试在片段的onStart方法中执行此操作: while (activity!!.supportFragmentManager!!.cancel按钮时抛出常见的java.lang.IllegalStateExceptio