我在 kotlin 流程中相对较新，我正在使用 android 中的流程创建登录模块。过去几天，我在 ViewModels 中收集它时一直被困在流程中，但是当我使用错误的凭据请求其缓存所有状态时，我遇到了问题。输入正确的凭据后，用户导航到主 Activity，但 MainActivity 的实例正在使用每个发出的状态创建：Example(User Enter 3 wrong Credential and 1 Right Credential: 4 Instance of MainActivity Created)。那么，有什么方法可以取消之前的发射并只显示最新的请求。我也在使用 collectLatest ，但它也不起作用。下面是代码。
登录活动
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(mViewBinding.root)
loginListener()
}
override fun onStart() {
super.onStart()
initViews()
handleNetworkChanges()
}
private fun observeLogin() {
lifecycleScope.launchWhenCreated {
mViewModel.loginCredentials.collect { state ->
when(state){
is State.Loading -> {
showLoading()
}
is State.Success -> {
Timber.d("I m in Success" + state.data)
val intent = Intent(this@LoginActivity,MainActivity::class.java)
startActivity(intent)
closeLoading()
finish()
}
is State.Error -> {
val errorResponse = gson.fromJson(state.message,LoginResponse::class.java)
showToast(errorResponse.messages)
closeLoading()
}
}
}
}
}
private fun loginListener() {
mViewBinding.neumorphButtonSignIn.setOnClickListener {
observeLogin()
phoneNumber = mViewBinding.edtPhoneNumber.text.toString()
pin = mViewBinding.oldPIN.text.toString()
if (phoneNumber.isValidPhone()) {
sendLoginCredentials(phoneNumber ,pin)
}
else {
mViewBinding.edtPhoneNumber.snack("Please Enter valid phone number") {
action("ok") {
dismiss()
}
}
}
}
}
private fun sendLoginCredentials(phoneNumber: String , pin: String) = mViewModel.postLoginCredentials("03XXXX" , "1234")
登录视图模型
@ExperimentalCoroutinesApi
@HiltViewModel
class LoginViewModel @Inject constructor(
private val loginRepository: LoginRepository,
) : ViewModel() {
private val _loginCredentials: MutableStateFlow<State<LoginResponse>> = MutableStateFlow(State.Empty())
val loginCredentials: StateFlow<State<LoginResponse>> get() = _loginCredentials
fun postLoginCredentials(phoneNumber: String, pin: String) {
Timber.d("postLoginCredentials: $phoneNumber + $pin")
_loginCredentials.value = State.loading()
viewModelScope.launch {
loginRepository.login(LoginRequest(phoneNumber,pin))
.map { response -> State.fromResource(response) }
.collect{state -> _loginCredentials.value = state }
}
}
}
登录存储库
class LoginRepository @Inject constructor(
private val apiInterface: APIInterface
) {
fun login(loginRequest: LoginRequest): Flow<ResponseAPI<LoginResponse>> {
return object : NetworkBoundRepository<LoginRequest, LoginResponse>() {
override suspend fun fetchFromRemote(): Response<LoginResponse> = apiInterface.createLoginRequest(
loginRequest
)
}.asFlow()
}
网络绑定存储库
abstract class NetworkBoundRepository<RESULT, REQUEST> {
fun asFlow() = flow<ResponseAPI<REQUEST>> {
val apiResponse = fetchFromRemote()
val remotePosts = apiResponse.body()
if (apiResponse.isSuccessful && remotePosts != null) {
emit(ResponseAPI.Success(remotePosts))
} else {
// Something went wrong! Emit Error state.
emit(ResponseAPI.Failed(apiResponse.errorBody()!!.string()))
}
}.catch { e ->
e.printStackTrace()
emit(ResponseAPI.Failed("Network error! Can't get latest posts."))
}
@MainThread
protected abstract suspend fun fetchFromRemote(): Response<REQUEST>
}
有什么方法可以创建 MainAcitivity 的一个实例而忽略较旧的发出响应？任何可以工作的操作员。非常感谢这方面的任何帮助。谢谢。