如何使用ViewModel将数据从DialogFragment发送到Fragment

问题描述

我正在尝试使用viewmodel将数据从DialogFragment发送到Fragment，但似乎fragment和Dialog片段都引用了viewmodel的不同实例。所以我无法访问数据。有什么办法可以解决这个问题？谢谢

这是我的片段

@AndroidEntryPoint
class FragmentToReceiveData:BaseFragment(R.layout.fragment_1){
   private val viewmodel: AddScheduleviewmodel by viewmodels()
   override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
      Log.d(TAG,"onViewCreated: $viewmodel")   // will print ...Myviewmodel@62274cc  

      viewmodel.dataFromDialog.observe(viewLifecycleOwner){
         //nothing happens
      } 
   }
   .
   .
   .
   private fun openDialog(){
    val action=FragmentToReceiveDataDirections.actionFragmentToReceiveDataToExampleDialog()
    findNavController().navigate(action)
    //exampleDialog.show(requireActivity().supportFragmentManager,"alarmDialog") //same issue      
   }
   
}

这是viewmodel：

class Myviewmodel @viewmodelInject constructor(){
   var dataFromDialog=mutablelivedata<SomeClass>()
   
   fun saveDataFromDialog(data:SomeClass){
     dataFromDialog.value=data      
   }
 }

这是我的DialogFragment

@AndroidEntryPoint
class ExampleDialog:DialogFragment() {
  val viewmodel:Myviewmodel by viewmodels()
  override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    Log.d(TAG,"onCreateDialog: $viewmodel")   // will print ...Myviewmodel@125436
    .
    .
    .
    viewmode.saveDataFromDialog(data)
  }
}

P.S：我正在使用单一活动架构，所以我不确定activityviewmodels（）是否是个好主意

解决方法

为了在片段之间共享ViewModel，可以使用activityViewModels()。例如，

class SharedViewModel : ViewModel() {
    ...
}

class MasterFragment : Fragment() {

    // Use the 'by activityViewModels()' Kotlin property delegate
    // from the fragment-ktx artifact
    private val model: SharedViewModel by activityViewModels()

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

class DetailFragment : Fragment() {

    // Use the 'by activityViewModels()' Kotlin property delegate
    // from the fragment-ktx artifact
    private val model: SharedViewModel by activityViewModels()

    override fun onViewCreated(view: View,savedInstanceState)
        ...
    }
}

请在此处的android文档中详细了解：https://developer.android.com/topic/libraries/architecture/viewmodel#sharing