我有我的视图模型创建内部实时数据观测,并将其与数据绑定连接期间发生在我身上的一个问题。现在我的代码部分看起来是这样的:片段:
类SearchFragment:片段(),可注射的{
@Inject lateinit var viewModelFactory: ViewModelProvider.Factory
@Inject lateinit var searchViewModel: SearchViewModel
private lateinit var disposable: Disposable
private var searchView: SearchView? = null
private var adapter: SearchCityListAdapter? = null
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val binding: SearchFragmentBinding = DataBindingUtil.inflate(inflater, R.layout.search_fragment, container, false)
binding.apply { viewModel = searchViewModel
setLifecycleOwner(this@SearchFragment)}
setHasOptionsMenu(true)
return binding.root
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
searchViewModel = ViewModelProviders.of(this, viewModelFactory).get(SearchViewModel::class.java)
submitViewModel()
}
private fun submitViewModel(){
viewModel.searchCityList.observe(this, Observer {it ->
if (adapter == null){
it?.let { adapter = SearchCityListAdapter(it)}.also {createAdapter()}
} else {
it?.let { adapter!!.updateList(it) }.also { adapter!!.notifyDataSetChanged() }
}
})
viewModel.responseStatus.observe(this, Observer {
it?.let { it ->
when(it.status){
Status.SUCCESS -> progressBar.visibility = View.INVISIBLE
Status.FAILURE -> progressBar.visibility = View.INVISIBLE
Status.ERROR -> progressBar.visibility = View.INVISIBLE
Status.LOADING ->progressBar.visibility = View.VISIBLE
} }
})
}
视图模型:
class SearchViewModel @Inject constructor(val haloApplication: HaloApplication): ViewModel() {
val progressBarVisibility: MediatorLiveData<Boolean> = MediatorLiveData()
private val responseStatus: MutableLiveData<Response> = MutableLiveData()
val searchCityList: MutableLiveData<SearchCityList> = MutableLiveData()
fun searchCity(cityName: String){
haloApplication.networkRepository.fetchCityList(cityName, responseStatus, searchCityList)
}
init {
progressBarVisibility.value = false
progressBarVisibility.addSource(responseStatus){
it?.let { when(it.status) {
Status.FAILURE -> progressBarVisibility.value = false
Status.ERROR -> progressBarVisibility.value = false
Status.SUCCESS -> progressBarVisibility.value = false
Status.LOADING -> progressBarVisibility.value = true
} }
}
}
}
XML布局文件:
<?xml version="1.0" encoding="utf-8"?>
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<data>
<variable
name="viewModel"
type="com.mbojec.halo.viewmodel.SearchViewModel"/>
</data>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.SearchFragment">
<ProgressBar
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/progressBar"
android:layout_gravity="center"
android:visibility="@{viewModel.progressBarVisibility, default=invisible}"/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/searchCityListRecycleView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
</layout>
DataBinder的文件:
import android.view.View
import androidx.databinding.BindingAdapter
@BindingAdapter("android:visibility")
fun setVisibility(view: View, value: Boolean) {
view.visibility = if (value) View.VISIBLE else View.INVISIBLE
}
对于一些不明原因的区段部分工作正常,但当有在responseStatus变化,并通过数据绑定的连接是无用的视图模型的部分永远不会触发。这不是我第一次在创建视图模型或改造的探讨的调解员的,但它是我第一次有这样的问题。我想每一个结果是一样的时间场景的的打和。首先,我WS指责新AndroidX库,但从GitHub的向日葵样品作品也细,所以我对这个时刻毫无头绪。
MediatorLiveData
只是开始观察人士通过addSource
添加时有一些观察MediatorLiveData
本身。由于没有什么是观察progressBarVisibility
,你不会得到任何回调。
你必须遵守progressBarVisibility接收回调调用onChanged。 (每个观察到需要一个观察一起工作)
突然想到做一些修改:
progressBarVisibility
并不需要是一个MediatorLiveData;responseStatus
public和观察它;progressBarVisibility
添加responseStatus
源。internal val progressBarVisibility: LiveData<Boolean> = Transformations.map(responseStatus) {
when (it.status) {
Status.LOADING -> true
Status.ERROR, Status.SUCCESS, Status.FAILURE -> false
}
}
现在,你可以观察progressBarVisibility
and接收回调。