Merge pull request #20 from lucassales2/lusa/vmextensions

View model tag extensions

Author: johsoe

app/src/main/java/com/monstarlab/arch/extensions/ViewErrorAware.kt

@@ -0,0 +1,5 @@
+package com.monstarlab.arch.extensions
+
+interface ViewErrorAware
+
+interface LoadingAware

app/src/main/java/com/monstarlab/arch/extensions/ViewModelEx.kt

@@ -0,0 +1,75 @@
+// Package set to androidx.lifecycle so we can have access to package private methods
+
+package androidx.lifecycle
+
+import com.monstarlab.arch.extensions.LoadingAware
+import com.monstarlab.arch.extensions.UseCaseResult
+import com.monstarlab.arch.extensions.ViewErrorAware
+import com.monstarlab.arch.extensions.onError
+import com.monstarlab.core.sharedui.errorhandling.ViewError
+import com.monstarlab.core.sharedui.errorhandling.mapToViewError
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+
+private const val ERROR_FLOW_KEY = "androidx.lifecycle.ErrorFlow"
+private const val LOADING_FLOW_KEY = "androidx.lifecycle.LoadingFlow"
+
+fun <T> T.sendViewError(viewError: ViewError) where T : ViewErrorAware, T : ViewModel {
+    viewModelScope.launch {
+        getErrorMutableSharedFlow().emit(viewError)
+    }
+}
+
+suspend fun <T> T.emitViewError(viewError: ViewError) where T : ViewErrorAware, T : ViewModel {
+    getErrorMutableSharedFlow().emit(viewError)
+}
+
+val <T> T.viewErrorFlow: SharedFlow<ViewError> where T : ViewErrorAware, T : ViewModel
+    get() {
+        return getErrorMutableSharedFlow()
+    }
+
+
+val <T> T.loadingFlow: StateFlow<Boolean> where T : LoadingAware, T : ViewModel
+    get() {
+        return loadingMutableStateFlow
+    }
+
+var <T> T.isLoading: Boolean where T : LoadingAware, T : ViewModel
+    get() {
+        return loadingMutableStateFlow.value
+    }
+    set(value) {
+        loadingMutableStateFlow.tryEmit(value)
+    }
+
+private val <T> T.loadingMutableStateFlow: MutableStateFlow<Boolean> where T : LoadingAware, T : ViewModel
+    get() {
+        val flow: MutableStateFlow<Boolean>? = getTag(LOADING_FLOW_KEY)
+        return flow ?: setTagIfAbsent(LOADING_FLOW_KEY, MutableStateFlow(false))
+    }
+
+private fun <T> T.getErrorMutableSharedFlow(): MutableSharedFlow<ViewError> where T : ViewErrorAware, T : ViewModel {
+    val flow: MutableSharedFlow<ViewError>? = getTag(ERROR_FLOW_KEY)
+    return flow ?: setTagIfAbsent(ERROR_FLOW_KEY, MutableSharedFlow())
+}
+
+fun <F, T> Flow<F>.bindLoading(t: T): Flow<F> where T : LoadingAware, T : ViewModel {
+    return this
+            .onStart {
+                t.loadingMutableStateFlow.value = true
+            }
+            .onCompletion {
+                t.loadingMutableStateFlow.value = false
+            }
+}
+
+fun <F, T> Flow<UseCaseResult<F>>.bindError(t: T): Flow<UseCaseResult<F>> where T : ViewErrorAware, T : ViewModel {
+    return this
+            .onError {
+                t.emitViewError(it.mapToViewError())
+            }
+}
+
+
+

app/src/main/java/com/monstarlab/features/login/LoginFragment.kt

@@ -4,6 +4,8 @@ import android.os.Bundle
 import android.view.View
 import androidx.core.view.isVisible
 import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.loadingFlow
+import androidx.lifecycle.viewErrorFlow
 import androidx.navigation.fragment.findNavController
 import androidx.transition.TransitionManager
 import com.google.android.material.snackbar.Snackbar
@@ -37,7 +39,6 @@ class LoginFragment : BaseFragment(R.layout.fragment_login) {
         }
 
         snackErrorFlow(viewModel.errorFlow, view)
-
         visibilityFlow(viewModel.loadingFlow, binding.loginProgressBar)
 
         collectFlow(viewModel.loadingFlow) { loading ->

app/src/main/java/com/monstarlab/features/login/LoginViewModel.kt

@@ -1,38 +1,28 @@
 package com.monstarlab.features.login
 
-import androidx.lifecycle.ViewModel
-import androidx.lifecycle.viewModelScope
-import com.monstarlab.arch.extensions.combineFlows
-import com.monstarlab.arch.extensions.onError
+import androidx.lifecycle.*
+import com.monstarlab.arch.extensions.LoadingAware
+import com.monstarlab.arch.extensions.ViewErrorAware
 import com.monstarlab.arch.extensions.onSuccess
-import com.monstarlab.core.sharedui.errorhandling.ViewError
-import com.monstarlab.core.sharedui.errorhandling.mapToViewError
-import com.monstarlab.core.usecases.resources.GetResourcesUseCase
 import com.monstarlab.core.usecases.user.LoginUseCase
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.launchIn
 import javax.inject.Inject
 
 class LoginViewModel @Inject constructor(
-        private val loginUseCase: LoginUseCase,
-        private val getResourcesUseCase: GetResourcesUseCase
-): ViewModel() {
+    private val loginUseCase: LoginUseCase
+) : ViewModel(), ViewErrorAware, LoadingAware {
 
-    val loadingFlow: MutableStateFlow<Boolean> = MutableStateFlow(false)
-    val errorFlow: MutableSharedFlow<ViewError> = MutableSharedFlow()
     val loginResultFlow: MutableSharedFlow<Boolean> = MutableSharedFlow()
 
     fun login(email: String, password: String) {
         loginUseCase
                 .login(email, password)
-                .onStart {
-                    loadingFlow.value = true
-                }.onSuccess {
+                .bindLoading(this)
+                .bindError(this)
+                .onSuccess {
                     loginResultFlow.emit(true)
-                }.onError {
-                    errorFlow.emit(it.mapToViewError())
-                }.onCompletion {
-                    loadingFlow.value = false
-                }.launchIn(viewModelScope)
+                }
+                .launchIn(viewModelScope)
     }
-
 }