我用 AppBarConfiguration

val appBarConfiguration = AppBarConfiguration
            .Builder(
                    R.id.preLoginFragment,
                    R.id.welcomeFragment
              )
            .build()

然后，您需要调用 setupActionBarWithNavController(this, navController, appBarConfiguration)

这里我声明了两个***片段，其中后退箭头不会显示在应用栏中.

Here I am declaring two top level fragments where the back arrow won't be shown in the app bar.