Android片段后台问题

我使用两个不同的片段替换函数。但第二个功能片段添加到后台为什么？如何解决此问题？谢谢

第一,

public static void switchScreen(Fragment fragment, String backStage) {
        FragmentTransaction fragments = mFragmentManager
                .beginTransaction()
                .setTransition(FragmentTransaction.TRANSIT_ENTER_MASK)
                .replace(R.id.screens, fragment, backStage)
                .addToBackStack(backStage);
        fragments.commitAllowingStateLoss();
    }

第二

public static void switchScreenNoHistory(Fragment fragment, String backStage) {
    FragmentTransaction fragments = mFragmentManager
            .beginTransaction()
            .setTransition(FragmentTransaction.TRANSIT_ENTER_MASK)
            .replace(R.id.screens, fragment);
    fragments.commit();
}

和我的背部按钮功能

private void backStackControl() {
        try {
            FragmentManager fragmentManager = this.getSupportFragmentManager();
            int backFragmentCount = (fragmentManager.getBackStackEntryCount() - 1);
            if (fragmentManager.getBackStackEntryCount() <= 0 || backFragmentCount <= 0) {
                finishAffinity();
            } else {
                fragmentManager.popBackStackImmediate();
            }
        } catch (Exception e) {
            Bugsnag.notify(new Exception(e));
        }
    }

private void backStackControl（）{
试一试{
FragmentManager FragmentManager=this.getSupportFragmentManager（）；
int backFragmentCount=（fragmentManager.getbackbackbackbackentrycount（）-1）；
如果（fragmentManager.GetBackbackEntryCount（）我相信有你想要的答案。祝你好运：）我看不出你有什么问题。当你按下后退按钮时会发生什么？