refactor: pass nav args to ViewModel using SavedStateHandle

app/src/main/java/com/geeksville/mesh/model/MetricsViewModel.kt

@@ -2,8 +2,10 @@ package com.geeksville.mesh.model
 
 import android.app.Application
 import android.net.Uri
+import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import androidx.navigation.toRoute
 import com.geeksville.mesh.ConfigProtos.Config.DisplayConfig.DisplayUnits
 import com.geeksville.mesh.CoroutineDispatchers
 import com.geeksville.mesh.MeshProtos.MeshPacket
@@ -14,12 +16,11 @@ import com.geeksville.mesh.android.Logging
 import com.geeksville.mesh.database.MeshLogRepository
 import com.geeksville.mesh.database.entity.MeshLog
 import com.geeksville.mesh.repository.datastore.RadioConfigRepository
+import com.geeksville.mesh.ui.Route
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.update
@@ -65,15 +66,16 @@ private fun MeshPacket.toPosition(): Position? = if (!decoded.wantResponse) {
 
 @HiltViewModel
 class MetricsViewModel @Inject constructor(
+    savedStateHandle: SavedStateHandle,
     private val app: Application,
     private val dispatchers: CoroutineDispatchers,
     private val meshLogRepository: MeshLogRepository,
     private val radioConfigRepository: RadioConfigRepository,
 ) : ViewModel(), Logging {
-    private val destNum = MutableStateFlow(0)
+    private val destNum = savedStateHandle.toRoute<Route.NodeDetail>().destNum
 
     private fun MeshLog.hasValidTraceroute(): Boolean = with(fromRadio.packet) {
-        hasDecoded() && decoded.wantResponse && from == 0 && to == destNum.value
+        hasDecoded() && decoded.wantResponse && from == 0 && to == destNum
     }
 
     fun getUser(nodeNum: Int) = radioConfigRepository.getUser(nodeNum)
@@ -83,7 +85,7 @@ class MetricsViewModel @Inject constructor(
     }
 
     fun clearPosition() = viewModelScope.launch(dispatchers.io) {
-        meshLogRepository.deleteLogs(destNum.value, PortNum.POSITION_APP_VALUE)
+        meshLogRepository.deleteLogs(destNum, PortNum.POSITION_APP_VALUE)
     }
 
     private val _state = MutableStateFlow(MetricsState.Empty)
@@ -100,51 +102,37 @@ class MetricsViewModel @Inject constructor(
             }
         }.launchIn(viewModelScope)
 
-        @OptIn(ExperimentalCoroutinesApi::class)
-        destNum.flatMapLatest { destNum ->
-            meshLogRepository.getTelemetryFrom(destNum).onEach { telemetry ->
-                _state.update { state ->
-                    state.copy(
-                        deviceMetrics = telemetry.filter { it.hasDeviceMetrics() },
-                        environmentMetrics = telemetry.filter {
-                            it.hasEnvironmentMetrics() && it.environmentMetrics.relativeHumidity >= 0f
-                        },
-                    )
-                }
+        meshLogRepository.getTelemetryFrom(destNum).onEach { telemetry ->
+            _state.update { state ->
+                state.copy(
+                    deviceMetrics = telemetry.filter { it.hasDeviceMetrics() },
+                    environmentMetrics = telemetry.filter {
+                        it.hasEnvironmentMetrics() && it.environmentMetrics.relativeHumidity >= 0f
+                    },
+                )
             }
         }.launchIn(viewModelScope)
 
-        @OptIn(ExperimentalCoroutinesApi::class)
-        destNum.flatMapLatest { destNum ->
-            meshLogRepository.getMeshPacketsFrom(destNum).onEach { meshPackets ->
-                _state.update { state ->
-                    state.copy(signalMetrics = meshPackets.filter { it.hasValidSignal() })
-                }
+        meshLogRepository.getMeshPacketsFrom(destNum).onEach { meshPackets ->
+            _state.update { state ->
+                state.copy(signalMetrics = meshPackets.filter { it.hasValidSignal() })
             }
         }.launchIn(viewModelScope)
 
-        @OptIn(ExperimentalCoroutinesApi::class)
-        destNum.flatMapLatest { destNum ->
-            combine(
-                meshLogRepository.getLogsFrom(nodeNum = 0, PortNum.TRACEROUTE_APP_VALUE),
-                meshLogRepository.getMeshPacketsFrom(destNum, PortNum.TRACEROUTE_APP_VALUE),
-            ) { request, response ->
-                _state.update { state ->
-                    state.copy(
-                        tracerouteRequests = request.filter { it.hasValidTraceroute() },
-                        tracerouteResults = response,
-                    )
-                }
+        combine(
+            meshLogRepository.getLogsFrom(nodeNum = 0, PortNum.TRACEROUTE_APP_VALUE),
+            meshLogRepository.getMeshPacketsFrom(destNum, PortNum.TRACEROUTE_APP_VALUE),
+        ) { request, response ->
+            _state.update { state ->
+                state.copy(
+                    tracerouteRequests = request.filter { it.hasValidTraceroute() },
+                    tracerouteResults = response,
+                )
             }
         }.launchIn(viewModelScope)
 
-        @OptIn(ExperimentalCoroutinesApi::class)
-        destNum.flatMapLatest { destNum ->
-            meshLogRepository.getMeshPacketsFrom(destNum, PortNum.POSITION_APP_VALUE).onEach { packets ->
-                _state.update { state ->
-                    state.copy(positionLogs = packets.mapNotNull { it.toPosition() })
-                }
-            }
+        meshLogRepository.getMeshPacketsFrom(destNum, PortNum.POSITION_APP_VALUE).onEach { packets ->
+            _state.update { state -> state.copy(positionLogs = packets.mapNotNull { it.toPosition() }) }
         }.launchIn(viewModelScope)
 
         debug("MetricsViewModel created")
@@ -155,13 +143,6 @@ class MetricsViewModel @Inject constructor(
         debug("MetricsViewModel cleared")
     }
 
-    /**
-     * Used to set the Node for which the user will see charts for.
-     */
-    fun setSelectedNode(nodeNum: Int) {
-        destNum.value = nodeNum
-    }
-
     /**
      * Write the persisted Position data out to a CSV file in the specified location.
      */

app/src/main/java/com/geeksville/mesh/model/RadioConfigViewModel.kt

@@ -3,8 +3,10 @@ package com.geeksville.mesh.model
 import android.app.Application
 import android.net.Uri
 import android.os.RemoteException
+import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import androidx.navigation.toRoute
 import com.geeksville.mesh.AdminProtos
 import com.geeksville.mesh.ChannelProtos
 import com.geeksville.mesh.ClientOnlyProtos.DeviceProfile
@@ -27,14 +29,17 @@ import com.geeksville.mesh.ui.AdminRoute
 import com.geeksville.mesh.ui.ConfigRoute
 import com.geeksville.mesh.ui.ModuleRoute
 import com.geeksville.mesh.ui.ResponseState
+import com.geeksville.mesh.ui.Route
 import com.google.protobuf.MessageLite
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
@@ -62,24 +67,16 @@ data class RadioConfigState(
 
 @HiltViewModel
 class RadioConfigViewModel @Inject constructor(
+    savedStateHandle: SavedStateHandle,
     private val app: Application,
     private val radioConfigRepository: RadioConfigRepository,
 ) : ViewModel(), Logging {
-
     private val meshService: IMeshService? get() = radioConfigRepository.meshService
 
-    private val _destNum = MutableStateFlow<Int?>(null)
+    private val destNum = savedStateHandle.toRoute<Route.RadioConfig>().destNum
     private val _destNode = MutableStateFlow<NodeEntity?>(null)
     val destNode: StateFlow<NodeEntity?> get() = _destNode
 
-    /**
-     * Sets the destination [NodeEntity] used in Radio Configuration.
-     * @param num Destination nodeNum (or null for our local [NodeEntity]).
-     */
-    fun setDestNum(num: Int?) {
-        _destNum.value = num
-    }
-
     private val requestIds = MutableStateFlow(hashSetOf<Int>())
     private val _radioConfigState = MutableStateFlow(RadioConfigState())
     val radioConfigState: StateFlow<RadioConfigState> = _radioConfigState
@@ -88,7 +85,8 @@ class RadioConfigViewModel @Inject constructor(
     val currentDeviceProfile get() = _currentDeviceProfile.value
 
     init {
-        combine(_destNum, radioConfigRepository.nodeDBbyNum) { destNum, nodes ->
+        @OptIn(ExperimentalCoroutinesApi::class)
+        radioConfigRepository.nodeDBbyNum.mapLatest { nodes ->
             nodes[destNum] ?: nodes.values.firstOrNull()
         }.onEach { _destNode.value = it }.launchIn(viewModelScope)
 

app/src/main/java/com/geeksville/mesh/ui/NavGraph.kt

@@ -120,7 +120,6 @@ class NavGraphFragment : ScreenFragment("NavGraph"), Logging {
             "NodeDetails" -> Route.NodeDetail(destNum!!)
             else -> Route.RadioConfig(destNum)
         }
-        model.setDestNum(destNum)
 
         return ComposeView(requireContext()).apply {
             setViewCompositionStrategy(ViewCompositionStrategy.DisposeOnViewTreeLifecycleDestroyed)

app/src/main/java/com/geeksville/mesh/ui/NodeDetail.kt

@@ -47,7 +47,6 @@ import androidx.compose.material.icons.filled.Thermostat
 import androidx.compose.material.icons.filled.WaterDrop
 import androidx.compose.material.icons.filled.Work
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -82,9 +81,6 @@ fun NodeDetailScreen(
     val state by viewModel.state.collectAsStateWithLifecycle()
 
     if (node != null) {
-        LaunchedEffect(node.num) {
-            viewModel.setSelectedNode(node.num)
-        }
         NodeDetailList(
             node = node,
             metricsState = state,