我正在从ViewModel 中的DialogFragment更新 LiveData值，但无法在Fragment中获取该值。
ViewModel:class OtpViewModel(private val otpUseCase: OtpUseCase, analyticsModel: IAnalyticsModel) : BaseViewModel(analyticsModel) {
override val globalNavModel = GlobalNavModel(titleId = R.string.otp_contact_title, hasGlobalNavBar = false)
private val _contactListLiveData = MutableLiveData<List<Contact>>()
val contactListLiveData: LiveData<List<Contact>>
get() = _contactListLiveData
private lateinit var cachedContactList: LiveData<List<Contact>>
private val contactListObserver = Observer<List<Contact>> {
_contactListLiveData.value = it
}
private lateinit var cachedResendOtpResponse: LiveData<LogonModel>
private val resendOTPResponseObserver = Observer<LogonModel> {
_resendOTPResponse.value = it
}
private var _resendOTPResponse = MutableLiveData<LogonModel>()
val resendOTPResponseLiveData: LiveData<LogonModel>
get() = _resendOTPResponse
var userSelectedIndex : Int = 0 //First otp contact selected by default
val selectedContact : LiveData<Contact>
get() = MutableLiveData(contactListLiveData.value?.get(userSelectedIndex))
override fun onCleared() {
if (::cachedContactList.isInitialized) {
cachedContactList.removeObserver(contactListObserver)
}
if (::cachedOtpResponse.isInitialized) {
cachedOtpResponse.removeObserver(otpResponseObserver)
}
super.onCleared()
}
fun updateIndex(pos: Int){
userSelectedIndex = pos
}
fun onChangeDeliveryMethod() {
navigate(
OtpVerificationHelpCodeSentBottomSheetFragmentDirections
.actionOtpContactVerificationBottomSheetToOtpChooseContactFragment()
)
}
fun onClickContactCancel() {
navigateBackTo(R.id.logonFragment, true)
}
fun retrieveContactList() {
cachedContactList = otpUseCase.fetchContactList()
cachedContactList.observeForever(contactListObserver)
}
fun resendOTP(contactId : String){
navigateBack()
cachedResendOtpResponse = otpUseCase.resendOTP(contactId)
cachedResendOtpResponse.observeForever(resendOTPResponseObserver)
}
}
BaseViewModel:abstract class BaseViewModel(val analyticsModel: IAnalyticsModel) : ViewModel() {
protected val _navigationCommands: SingleLiveEvent<NavigationCommand> = SingleLiveEvent()
val navigationCommands: LiveData<NavigationCommand> = _navigationCommands
abstract val globalNavModel: GlobalNavModel
/**
* Posts a navigation event to the navigationsCommands LiveData observable for retrieval by the view
*/
fun navigate(directions: NavDirections) {
_navigationCommands.postValue(NavigationCommand.ToDirections(directions))
}
fun navigate(destinationId: Int) {
_navigationCommands.postValue(NavigationCommand.ToDestinationId(destinationId))
}
fun navigateBack() {
_navigationCommands.postValue(NavigationCommand.Back)
}
fun navigateBackTo(destinationId: Int, isInclusive: Boolean) {
_navigationCommands.postValue(NavigationCommand.BackTo(destinationId, isInclusive))
}
open fun init() {
// DEFAULT IMPLEMENTATION - override to initialize your view model
}
/**
* Called from base fragment when the view has been created.
*/
fun onViewCreated() {
analyticsModel.onNewState(getAnalyticsPathCrumb())
}
/**
* gets the Path for the current page to be used for the trackstate call
*
* Override this method if you need to modify the path
*
* the page id for the track state call will be calculated in the following manner
* 1) analyticsPageId
* 2) titleId
* 3) the page title string
*/
protected fun getAnalyticsPathCrumb() : AnalyticsBreadCrumb {
return analyticsBreadCrumb {
pathElements {
if (globalNavModel.analyticsPageId != null) {
waPath {
path = PathElement(globalNavModel.analyticsPageId as Int)
}
} else if (globalNavModel.titleId != null) {
waPath {
path = PathElement(globalNavModel.titleId as Int)
}
} else {
waPath {
path = PathElement(globalNavModel.title ?: "")
}
}
}
}
}
}
对话框片段:
class OtpVerificationHelpCodeSentBottomSheetFragment : BaseBottomSheetDialogFragment(){
private lateinit var rootView: View
lateinit var binding: BottomSheetFragmentOtpVerificationHelpCodeSentBinding
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
viewModel = getViewModel<OtpViewModel>()
binding = DataBindingUtil.inflate(inflater, R.layout.bottom_sheet_fragment_otp_verification_help_code_sent, container, false)
rootView = binding.root
return rootView
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val otpViewModel = (viewModel as OtpViewModel)
binding.viewmodel = otpViewModel
otpViewModel.resendOTPResponseLiveData.observe(viewLifecycleOwner, Observer {
it?.let { resendOtpResponse ->
if(resendOtpResponse.statusCode.equals("000")){
//valid status code
requireActivity().toastMessageOtp(getString(R.string.otp_code_verification_sent))
}else{
//show the error model
//it?.errorModel?.let { it1 -> handleDiasNetworkError(it1) }
}
}
})
}
}
我从 DialogFragment 的xml文件中调用viewmodel的 resendOTP(contactId:String)方法: <TextView
android:id="@+id/verification_help_code_sent_resend_code"
style="@style/TruTextView.SubText2.BottomActions"
android:layout_height="@dimen/spaceXl"
android:gravity="center_vertical"
android:text="@string/verification_help_resend_code"
android:onClick="@{() -> viewmodel.resendOTP(Integer.toString(viewmodel.userSelectedIndex))}"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/top_guideline" />
现在，每当我尝试从Fragment调用resendOTPResponseLiveData时，它都不会被调用:override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
Log.d("OtpVerify" , "OnViewCreatedCalled")
viewModel.onViewCreated()
val otpViewModel = (viewModel as OtpViewModel)
binding.lifecycleOwner = this
binding.viewmodel = otpViewModel
binding.toAuthenticated = OtpVerifyFragmentDirections.actionOtpVerifyFragmentToAuthenticatedActivity()
binding.toVerificationBtmSheet = OtpVerifyFragmentDirections.actionOtpVerifyFragmentToOtpContactVerificationCodeSentBottomSheet()
otpViewModel.resendOTPResponseLiveData.observe(viewLifecycleOwner, Observer {
if(it?.statusCode.equals("000")){
//valid status code
requireActivity().toastMessageOtp(getString(R.string.otp_code_verification_sent))
}else{
//show the error model
it?.errorModel?.let { it1 -> handleDiasNetworkError(it1) }
}
})
}
所以我在这里做什么错。
编辑
基本上，我需要在dialogfragment中单击clicklistener(重新发送按钮单击)，并需要在片段中读取它。因此，我使用了SharedViewModel的概念。
因此，我在ViewModel中进行了必要的更改:private val selected = MutableLiveData<LogonModel>()
fun select(logonModel: LogonModel) {
selected.value = logonModel
}
fun getSelected(): LiveData<LogonModel> {
return selected
}
在DialogFragment中: otpViewModel.resendOTPResponseLiveData.observe(viewLifecycleOwner, Observer{
otpViewModel.select(it);
})
在我想读取值的片段中:otpViewModel.getSelected().observe(viewLifecycleOwner, Observer {
Log.d("OtpVerify" , "ResendCalled")
// Update the UI.
if(it?.statusCode.equals("000")){
//valid status code
requireActivity().toastMessageOtp(getString(R.string.otp_code_verification_sent))
}else{
//show the error model
it?.errorModel?.let { it1 -> handleDiasNetworkError(it1) }
}
})
但是它仍然无法正常工作。
编辑:
片段的ViewModel源:viewModel = getSharedViewModel<OtpViewModel>(from = {
Navigation.findNavController(container as View).getViewModelStoreOwner(R.id.two_step_authentication_graph)
})
对话框片段的ViewModel源:viewModel = getViewModel<OtpViewModel>()
最佳答案
问题是您实际上没有在Fragment和Dialog之间共享ViewModel。要共享ViewModel的实例，必须从相同的ViewModelStore中检索它们。
您用于检索ViewModels的语法似乎来自第三方框架。我觉得大概Koin。
如果是这种情况，请注意，在Koin中，getViewModel从Fragment自己的ViewModelStore中检索ViewModel。因此，您正在从DialogFragment中的ViewModelStore中检索ViewModel。另一方面，在Fragment中，您使用getSharedViewModel对其进行检索，您可以在其中指定应从哪个ViewModelStore检索ViewModel。因此，您正在从两个不同的ViewModelStores中检索ViewModel，因此，得到了两个不同的ViewModel。与其中一个进行交互不会影响另一个，因为它们不是同一实例。
要解决此问题，您应该从同一个ViewModelStore中检索Fragment和DialogFragment中的ViewModel。例如，您可以在两者中都使用getSharedViewModel，可以在每个位置手动指定相同的ViewModelStore，或者甚至不指定哪个Koin将默认为其Activity的ViewModelStore。
您甚至还可以在Fragment中使用getViewModel，然后将其自己的特定ViewModelStore传递给DialogFragment，然后在其中使用getSharedViewModel，指定传递的Fragment的ViewModelStore。