如何使用导航从其他片段隐藏主机活动中的视图

Posted 2023-04-19

【中文标题】如何使用导航从其他片段隐藏主机活动中的视图

【英文标题】：How to hide a view in the host activity from other fragment using navigation

【发布时间】：2021-12-22 05:46:51

【问题描述】：

activity_main.xml

 <androidx.fragment.app.FragmentContainerView
   android:id="@+id/nav_host_fragment"
   android:name="androidx.navigation.fragment.NavHostFragment"
   android:layout_
   android:layout_
   app:layout_constraintLeft_toLeftOf="parent"
   app:layout_constraintRight_toRightOf="parent"
   app:layout_constraintTop_toTopOf="parent"
   app:layout_constraintBottom_toBottomOf="parent"
   app:defaultNavHost="true"
   app:navGraph="@navigation/nav_graph" >
</androidx.fragment.app.FragmentContainerView>

<androidx.constraintlayout.widget.ConstraintLayout
  android:id="@+id/bottom_controls"
  android:layout_
  android:layout_
  android:onClick="onSongInfoClick"
  android:background="@drawable/lyt_rounded_bottom_music"
  android:paddingStart="10dp"
  android:paddingEnd="10dp"
  android:elevation="25dp"
  app:layout_constraintTop_toBottomOf="@id/nav_host_fragment">

起始目的地是一个由各种选项卡组成的ViewPagerFragment。

当我从 activity_main 中单击 bottom_controls 视图时，我正在导航到 SongDetailsFragment

我不想在 songDetailsFragment

中显示

bottom_controls

这是我的尝试：

MainActivity.kt

val currentFragment = supportFragmentManager.currentNavigationFragment
if(currentFragment !== SongDetailsFragment())

  viewModel.showMiniPlayer()

else
  viewModel.hideMiniPlayer()

SongDetailsFragment.kt

class SongDetailsFragment : BaseSongDetailFragment() 
  .....

BaseSongDetailFragment.kt

 open class BaseSongDetailFragment : Fragment() 

 private val songDetailViewModel by sharedViewModel<SongDetailViewModel>()
 protected val mainViewModel by inject<MainViewModel>()


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

 override fun onPause() 
 showHideBottomSheet()
 super.onPause()
 

 override fun onResume() 
 showHideBottomSheet()
 super.onResume()


private fun showHideBottomSheet() 
 val currentData = songDetailViewModel.currentData.value ?: return
 if (currentData.id == 0L) return

 val currentFragment = 
 requireActivity().supportFragmentManager.currentNavigationFragment

 if(currentFragment ==  this as SongDetailsFragment)
    mainViewModel.hideMiniPlayer()
 

 else
     mainViewModel.showMiniPlayer()
  
  

问题：

当我第一次启动应用并导航到 songDetailsFragment 时，它会显示 bottom_controls 视图。

随后，它不显示。

我希望它根本不显示。

【参考方案1】：

您可以在活动中使用OnDestinationChangedListener 来监听 currentDestination 的变化。

navController.addOnDestinationChangedListener  _, destination, _ ->
    if (destination.id == R.id.songDetailsFragment)
        viewModel.hideMiniPlayer()
    else
        viewModel.showMiniPlayer()

【讨论】：

谢谢！！！！！！