我得到了3个片段和1个活动。MainActivity，CameraFragment，HomeFragment，HistoryFragment
我只是想保存所有HistoryFragment状态，这样每当用户访问它时，它就不会再次重新创建。
无论如何，我已经找到了最常见的解决方案与fragmentManager
这是我所有的密码

MainActivity.kt

class MainActivity : AppCompatActivity() {
    
         private val historyFragment = HistoryFragment()
         private val homeFragment = HomeFragment()
         private val cameraFragment = CameraFragment()
         private val fragmentManager = supportFragmentManager
    
    
         override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
    
         val ft = fragmentManager.beginTransaction()
                   ft.add(R.id.fragmentContainerView, historyFragment, Constants.TAG_HISTORY)
                     .hide(historyFragment)
                     .add(R.id.fragmentContainerView, homeFragment, Constants.TAG_HOME)
    
         cameraViewModel.activeFragment = if (hasPermission()) {
                     //camera
                     ft.add(R.id.fragmentContainerView, cameraFragment, Constants.TAG_CAMERA)
                     ft.hide(homeFragment)
    
                     cameraFragment
             } else {
                     //home
                     homeFragment
                    }
         ft.commit()

         val navHostFragment =
            supportFragmentManager.findFragmentById(R.id.fragmentContainerView) as NavHostFragment
         val navController = navHostFragment.findNavController()
         binding.bottomNav.setupWithNavController(navController)

         binding.bottomNav.setOnItemSelectedListener { item ->
             when (item.itemId) {
                 R.id.historyFragment -> {

                 when (cameraViewModel.activeFragment) {
                    is HomeFragment -> fragmentManager.beginTransaction().hide(cameraViewModel.activeFragment).show(historyFragment).commit()
                 }
         
                cameraViewModel.activeFragment = historyFragment
                item.isChecked = true
                true
            }
            
    }
}

字符串

历史片段.kt

class HistoryFragment : Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
        ): View {

        binding = FragmentHistoryBinding.inflate(inflater, container, false)

        // tool bar
        (activity as AppCompatActivity).setSupportActionBar(binding.toolBarHistory)

        val appBarConfiguration = AppBarConfiguration(
            setOf(R.id.historyFragment, R.id.homeFragment, R.id.cameraFragment)
        )

        NavigationUI.setupActionBarWithNavController(requireActivity() as AppCompatActivity, findNavController(), appBarConfiguration)

        return binding.root
    }
}

型

fragment_history.xml中的工具栏

<androidx.appcompat.widget.Toolbar
            android:id="@+id/tool_bar_history"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="16dp"/>

型

问题是当我打开应用程序时，MainActivity运行，然后显示homeFragment，当我单击底部导航中的历史记录项目时，homeFragment得到隐藏，它显示historyFragment，但标题栏中的标签Home不是History**

我使用过Logcat，我发现当我在historyFragment中调用：navController.currentDestination?.id时，我会得到homeFragment的id
我希望你给予我解决这个或任何其他方式保存片段没有错误提前感谢