Code review [#25] P4, P5, P6, P7, P8 - Kotlin Channels, removed unnec…

…essary comments and shackbars, Ui states now in ViewModels

app/build.gradle

@@ -68,6 +68,9 @@ dependencies {
     // LiveData
     implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.3.1"
 
+    // Lifecycle
+    implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.4.0-alpha01"
+
     // Fragment
     implementation "androidx.fragment:fragment-ktx:1.3.3"
 

app/src/main/AndroidManifest.xml

@@ -22,9 +22,7 @@
             android:name="preloaded_fonts"
             android:resource="@array/preloaded_fonts" />
 
-        <activity
-            android:name=".presentation.MainActivity"
-            android:screenOrientation="portrait">
+        <activity android:name=".presentation.MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/com/edwin/weatherapp/extentions/AddMarker.kt → app/src/main/java/com/edwin/weatherapp/extensions/AddMarker.kt

@@ -1,4 +1,4 @@
-package com.edwin.weatherapp.extentions
+package com.edwin.weatherapp.extensions
 
 import com.google.android.gms.maps.GoogleMap
 import com.google.android.gms.maps.model.Marker

app/src/main/java/com/edwin/weatherapp/extentions/AnimateCardView.kt → app/src/main/java/com/edwin/weatherapp/extensions/AnimateCardView.kt

@@ -1,4 +1,4 @@
-package com.edwin.weatherapp.extentions
+package com.edwin.weatherapp.extensions
 
 import android.view.View
 import androidx.cardview.widget.CardView

app/src/main/java/com/edwin/weatherapp/extentions/LoadImage.kt → app/src/main/java/com/edwin/weatherapp/extensions/LoadImage.kt

@@ -1,4 +1,4 @@
-package com.edwin.weatherapp.extentions
+package com.edwin.weatherapp.extensions
 
 import android.content.Context
 import android.widget.ImageView

app/src/main/java/com/edwin/weatherapp/extentions/MarkerIconFromVector.kt → app/src/main/java/com/edwin/weatherapp/extensions/MarkerIconFromVector.kt

@@ -1,4 +1,4 @@
-package com.edwin.weatherapp.extentions
+package com.edwin.weatherapp.extensions
 
 import android.content.Context
 import android.graphics.Bitmap

app/src/main/java/com/edwin/weatherapp/extentions/ShowSnackbar.kt → app/src/main/java/com/edwin/weatherapp/extensions/ShowSnackbar.kt

@@ -1,4 +1,4 @@
-package com.edwin.weatherapp.extentions
+package com.edwin.weatherapp.extensions
 
 import android.view.View
 import androidx.annotation.StringRes

app/src/main/java/com/edwin/weatherapp/presentation/map/MapFragment.kt

@@ -12,15 +12,20 @@ import androidx.activity.result.contract.ActivityResultContracts.RequestPermissi
 import androidx.appcompat.app.AlertDialog
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.flowWithLifecycle
+import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
 import com.edwin.domain.exception.MapException
 import com.edwin.weatherapp.R
 import com.edwin.weatherapp.databinding.MapFragmentBinding
-import com.edwin.weatherapp.extentions.*
+import com.edwin.weatherapp.extensions.*
 import com.google.android.gms.maps.CameraUpdateFactory
 import com.google.android.gms.maps.GoogleMap
 import com.google.android.gms.maps.OnMapReadyCallback
 import com.google.android.gms.maps.model.LatLng
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import org.koin.androidx.viewmodel.ext.android.viewModel
 
 class MapFragment : Fragment(R.layout.map_fragment), OnMapReadyCallback {
@@ -39,24 +44,62 @@ class MapFragment : Fragment(R.layout.map_fragment), OnMapReadyCallback {
         RequestPermission()
     ) { isGranted: Boolean ->
         if (isGranted) {
-            //Если разрешение выдано показываем Snackbar и выполняем действие
-            showSnackbar(getString(R.string.permission_granted))
-            moveCameraToCurrentLocation()
-        } else {
-            showSnackbar(getString(R.string.permission_denied))
+            viewModel.getFusedLocation()
         }
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         binding = MapFragmentBinding.bind(view)
+        setupObservers()
         binding.apply {
             mapView.onCreate(savedInstanceState)
             mapView.getMapAsync(this@MapFragment)
         }
         setHasOptionsMenu(true)
     }
 
+    private fun setupObservers() {
+        val uiStateFlow = viewModel.uiState.flowWithLifecycle(lifecycle, Lifecycle.State.STARTED)
+        uiStateFlow.onEach { state ->
+            when (state) {
+                is MapViewModel.MapUiState.Loading -> binding.progressBar.visibility = View.VISIBLE
+                is MapViewModel.MapUiState.CurrentLocationLoaded -> {
+                    binding.progressBar.visibility = View.INVISIBLE
+                    val latLng = LatLng(state.location.latitude, state.location.longitude)
+                    moveCameraToCurrentLocation(latLng)
+                }
+                is MapViewModel.MapUiState.AddressLoaded -> {
+                    binding.progressBar.visibility = View.INVISIBLE
+                    setupShowWeatherWindow(state.address)
+                }
+                is MapViewModel.MapUiState.Error -> binding.progressBar.visibility = View.INVISIBLE
+                else -> Unit
+            }
+        }.launchIn(viewLifecycleOwner.lifecycleScope)
+
+        val eventsFlow = viewModel.eventsFlow.flowWithLifecycle(lifecycle, Lifecycle.State.STARTED)
+        eventsFlow.onEach { event ->
+            when (event) {
+                is MapViewModel.ActionState.ShowError -> {
+                    when (event.throwable) {
+                        is MapException.GeocoderFailed -> showSnackbar(
+                            getString(R.string.check_connection_error_text)
+                        )
+                        is MapException.CityNotFound -> showSnackbar(
+                            getString(R.string.no_city_error_text)
+                        )
+                        is MapException.NoLastLocation -> {
+                            showSnackbar(getString(R.string.current_location_error_text)) {
+                                action(R.string.action_retry) { viewModel.getFusedLocation() }
+                            }
+                        }
+                    }
+                }
+            }
+        }.launchIn(viewLifecycleOwner.lifecycleScope)
+    }
+
     override fun onMapReady(googleMap: GoogleMap) {
         map = googleMap
         checkPermissions()
@@ -65,47 +108,30 @@ class MapFragment : Fragment(R.layout.map_fragment), OnMapReadyCallback {
             map.addMarker {
                 position(latLng)
             }
-            // Если текущий зум камеры выше стандартного, то не уменьшаем его
             val cameraPosition = if (googleMap.cameraPosition.zoom > ON_CLICK_MAP_ZOOM) {
                 CameraUpdateFactory.newLatLng(latLng)
             } else {
                 CameraUpdateFactory.newLatLngZoom(latLng, ON_CLICK_MAP_ZOOM)
             }
             map.animateCamera(cameraPosition)
-            // Делаем progressBar видимым и обновляем Address во ViewModel
-            binding.progressBar.visibility = View.VISIBLE
             viewModel.getAddress(latLng.latitude, latLng.longitude)
         }
-        viewModel.address.observe(viewLifecycleOwner, { result ->
-            // При успешном получении Address убираем progressBar и показываем окно
-            result.onSuccess { address ->
-                binding.progressBar.visibility = View.INVISIBLE
-                setupShowWeatherWindow(address)
-            }
-            // При неудачном получении Address убираем progressBar и обрабатываем ошибки
-            result.onFailure { exception ->
-                binding.progressBar.visibility = View.INVISIBLE
-                when (exception) {
-                    is MapException.GeocoderFailed -> showSnackbar(
-                        getString(R.string.check_connection_error_text)
-                    )
-                    is MapException.CityNotFound -> showSnackbar(
-                        getString(R.string.no_city_error_text)
-                    )
-                }
-            }
-        })
+    }
+
+    private fun moveCameraToCurrentLocation(latLng: LatLng) {
+        val cameraPosition = CameraUpdateFactory.newLatLngZoom(latLng, ON_START_MAP_ZOOM)
+        map.animateCamera(cameraPosition)
+        map.addMarker {
+            position(latLng)
+            title(getString(R.string.marker_title))
+            icon(requireContext(), R.drawable.ic_my_location)
+        }
     }
 
     private fun setupShowWeatherWindow(address: Address) = with(binding) {
         cityName.text = address.locality
         cityLatlng.text = getString(R.string.cityLatlng, address.latitude, address.longitude)
-        // По клику на кнопку закрытия окна скрываем его с анимацией
-        closeWindowButton.setOnClickListener {
-            showWeatherWindow.animateOut()
-        }
-        /* По клику на кнопку "Show weather" открываем WeatherDetailsFragment.
-        Через SafeArgs передаем в него название города и его координаты */
+        closeWindowButton.setOnClickListener { showWeatherWindow.animateOut() }
         showWeatherButton.setOnClickListener {
             val action = MapFragmentDirections.actionMapFragmentToWeatherDetailsFragment(
                 address.locality, address.latitude.toFloat(), address.longitude.toFloat()
@@ -121,50 +147,15 @@ class MapFragment : Fragment(R.layout.map_fragment), OnMapReadyCallback {
                 requireContext(),
                 LOCATION_PERMISSION
             ) == PackageManager.PERMISSION_GRANTED -> {
-                moveCameraToCurrentLocation()
+                viewModel.getFusedLocation()
             }
-            // Если пользователь отказался давать разрешение, то пытаемся убедить его :)
             shouldShowRequestPermissionRationale(LOCATION_PERMISSION) -> {
                 showDialog()
             }
             else -> requestPermissionLauncher.launch(LOCATION_PERMISSION)
         }
     }
 
-    private fun moveCameraToCurrentLocation() {
-        binding.progressBar.visibility = View.VISIBLE
-        // Обновляем значение LiveData во ViewModel
-        viewModel.getFusedLocation()
-        viewModel.fusedLocation.observe(viewLifecycleOwner, { result ->
-            // Если локация пользователя получена успешно, то приближаем камеру и ставим маркер
-            result.onSuccess { location ->
-                binding.progressBar.visibility = View.INVISIBLE
-                val latLng = LatLng(location.latitude, location.longitude)
-                val cameraPosition = CameraUpdateFactory.newLatLngZoom(latLng, ON_START_MAP_ZOOM)
-                map.animateCamera(cameraPosition)
-                map.addMarker {
-                    position(latLng)
-                    title(getString(R.string.marker_title))
-                    icon(requireContext(), R.drawable.ic_my_location)
-                }
-            }
-            // Если при получении локации возникли исключения, то обрабатываем их
-            result.onFailure { exception ->
-                binding.progressBar.visibility = View.INVISIBLE
-                when (exception) {
-                    is MapException.NoLastLocation -> {
-                        showSnackbar(getString(R.string.current_location_error_text)) {
-                            action(R.string.action_retry) {
-                                binding.progressBar.visibility = View.VISIBLE
-                                viewModel.getFusedLocation()
-                            }
-                        }
-                    }
-                }
-            }
-        })
-    }
-
     private fun showDialog() {
         AlertDialog.Builder(requireContext(), R.style.AlertDialogTheme)
             .setMessage(getString(R.string.permission_dialog_message))
@@ -183,7 +174,6 @@ class MapFragment : Fragment(R.layout.map_fragment), OnMapReadyCallback {
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
         return when (item.itemId) {
-            // При клике на иконку поиска в меню показываем Snackbar
             R.id.action_search -> {
                 showSnackbar(getString(R.string.search_toast_text))
                 true

app/src/main/java/com/edwin/weatherapp/presentation/map/MapViewModel.kt

@@ -2,32 +2,58 @@ package com.edwin.weatherapp.presentation.map
 
 import android.location.Address
 import android.location.Location
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.edwin.domain.usecase.GetAddressFromGeocoderUseCase
 import com.edwin.domain.usecase.GetFusedLocationUseCase
-import com.edwin.weatherapp.extentions.asLiveData
-import kotlinx.coroutines.flow.single
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
 
 class MapViewModel(
     private val getFusedLocationUseCase: GetFusedLocationUseCase,
     private val getAddressFromGeocoderUseCase: GetAddressFromGeocoderUseCase
 ) : ViewModel() {
 
-    private val _fusedLocation = MutableLiveData<Result<Location>>()
-    val fusedLocation: LiveData<Result<Location>> = _fusedLocation.asLiveData()
+    private val _uiState = MutableStateFlow<MapUiState>(MapUiState.Default)
+    val uiState: StateFlow<MapUiState> = _uiState.asStateFlow()
 
-    private val _address = MutableLiveData<Result<Address>>()
-    val address: LiveData<Result<Address>> = _address.asLiveData()
+    private val eventChannel = Channel<ActionState>(Channel.BUFFERED)
+    val eventsFlow = eventChannel.receiveAsFlow()
 
     fun getFusedLocation() = viewModelScope.launch {
-        _fusedLocation.value = getFusedLocationUseCase.invoke().single()
+        _uiState.value = MapUiState.Loading
+        val location = getFusedLocationUseCase.invoke().single()
+        location.fold(
+            onSuccess = { _uiState.value = MapUiState.CurrentLocationLoaded(it) },
+            onFailure = {
+                _uiState.value = MapUiState.Error
+                eventChannel.send(ActionState.ShowError(it))
+            }
+        )
     }
 
     fun getAddress(latitude: Double, longitude: Double) = viewModelScope.launch {
-        _address.value = getAddressFromGeocoderUseCase.invoke(latitude, longitude).single()
+        _uiState.value = MapUiState.Loading
+        val address = getAddressFromGeocoderUseCase.invoke(latitude, longitude).single()
+        address.fold(
+            onSuccess = { _uiState.value = MapUiState.AddressLoaded(it) },
+            onFailure = {
+                _uiState.value = MapUiState.Error
+                eventChannel.send(ActionState.ShowError(it))
+            }
+        )
+    }
+
+    sealed class MapUiState {
+        object Loading : MapUiState()
+        object Error : MapUiState()
+        object Default : MapUiState()
+        data class CurrentLocationLoaded(val location: Location) : MapUiState()
+        data class AddressLoaded(val address: Address) : MapUiState()
+    }
+
+    sealed class ActionState {
+        data class ShowError(val throwable: Throwable) : ActionState()
     }
 }