Menu Provider无法添加菜单至Toolbar问题排查求助

我刚接触Android Studio，折腾两天都没能让Menu Provider正常工作，求帮忙排查问题，万分感谢！

当前使用主题为Theme.Material3.Light.NoActionBar，试过给Toolbar设置空菜单和不设置菜单两种情况，均无效果。也尝试让Fragment直接继承MenuProvider接口，结果依旧。

布局代码（activity.xml中Toolbar部分） #

<androidx.coordinatorlayout.widget.CoordinatorLayout
    android:id="@+id/coordinator_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintTop_toTopOf="parent">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:minHeight="?attr/actionBarSize">

        <com.google.android.material.appbar.MaterialToolbar
            android:id="@+id/home_top_bar"
            style="@style/Widget.App.Toolbar.Centered"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:menu="@menu/empty_menu"/>

    </com.google.android.material.appbar.AppBarLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Activity代码 #

class HomeActivity : AppCompatActivity() {

private lateinit var binding: ActivityHomeBinding
private lateinit var navController: NavController
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    binding = DataBindingUtil.setContentView(this, R.layout.activity_home)

    val navHostFragment = supportFragmentManager.findFragmentById(R.id.home_nav_controller) as NavHostFragment
    navController = navHostFragment.navController
    val appBarConfiguration = AppBarConfiguration(navController.graph)

    binding.homeTopBar.apply {
        setupWithNavController(navController, appBarConfiguration)
    }
}
}

Fragment代码 #

class HomeFragment : Fragment() {

    private lateinit var binding: FragmentHomeBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        binding = FragmentHomeBinding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val menuHost: MenuHost = requireActivity()

        menuHost.addMenuProvider(object : MenuProvider {
            override fun onCreateMenu(menu: Menu, menuInflater: MenuInflater) {
                menuInflater.inflate(R.menu.home_menu, menu)
            }

            override fun onMenuItemSelected(menuItem: MenuItem): Boolean {
                when(menuItem.itemId) {
                    R.id.account -> {
                        view.findNavController().navigate(R.id.action_homeFragment_to_userFragment)
                        return true
                    }
                    R.id.join_game -> {
                        view.findNavController().navigate(R.id.action_homeFragment_to_joinGameFragment)
                        return true
                    } else -> return false
                }
            }
        }, viewLifecycleOwner, Lifecycle.State.RESUMED)


        binding.apply {
            lifecycleOwner = viewLifecycleOwner
            //viewModel = sharedViewModel
            homeFragment = this@HomeFragment
        }
    }

    fun newGame() {
        view?.findNavController()?.navigate(R.id.action_homeFragment_to_newGameFragment)
    }
}

• 修正MenuHost获取方式：当前用requireActivity()作为MenuHost，但结合Navigation Component时，Fragment自身就是MenuHost，应改为：

  val menuHost: MenuHost = this
  

• 移除Toolbar固定菜单绑定：删除布局中MaterialToolbar的app:menu="@menu/empty_menu"属性，避免和MenuProvider的菜单冲突。
• 调整生命周期绑定状态：将MenuProvider的生命周期从Lifecycle.State.RESUMED改为Lifecycle.State.STARTED，确保菜单在Fragment启动阶段就被加载：

  menuHost.addMenuProvider(/* ... */, viewLifecycleOwner, Lifecycle.State.STARTED)
  

• 手动关联Toolbar到ActionBar：在Activity中添加setSupportActionBar(binding.homeTopBar)，让MenuProvider的菜单自动关联到当前Toolbar。
• 检查菜单资源配置：确认home_menu.xml中的菜单项没有设置android:visible="false"等隐藏属性，ID配置正确。

内容的提问来源于stack exchange，提问作者Teoneeee