Android BottomNavigation 未使用导航 Controller 正确突出显示

Question

我正在尝试实现 Nagivation来自 Android 架构组件。我能够成功地浏览我的 fragment 。我试图将它附加到我的底部导航，但我无法正确使用它。我可以使用 Navigation.findNavController(View).navigate(R.id.Fragment) 在 fragment 之间成功导航，但是当我使用任何 UI 组件或后退按钮执行此操作时，底部导航的突出显示是没有变化，如下图所示

我的MainActivity.kt代码如下，

class MainActivity : AppCompatActivity() {


    private lateinit var navController: NavController


    private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
        when (item.itemId) {
            R.id.navigation_home -> {
                navController.navigate(R.id.homeFragment)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_dashboard -> {
                navController.navigate(R.id.addEmotionFragment)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_notifications -> {
                return@OnNavigationItemSelectedListener true
            }
        }
        false
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        navController = Navigation.findNavController(this, R.id.nav_host)
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener)
    }


}

对于 HomeFragment.kt

class HomeFragment : Fragment() {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_home, container, false)
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        button.setOnClickListener {
            Navigation.findNavController(it).navigate(R.id.addEmotionFragment)
        }
    }
}

Answer 1

尝试使用navigation-ui。

implementation 'androidx.navigation:navigation-ui:' + navigationVersion //currently 1.0.0-alpha05

在 Activity 中

    navController = Navigation.findNavController(this, R.id.nav_host)
    NavigationUI.setupWithNavController(bottomNavigation, navController)

并确保您的 fragment ID 与菜单 ID 匹配。

<item
        android:id="@+id/homeFragment"
        android:title="Home"/>