Fixed backpress behaviour BatteryDetails.kt

app/src/main/java/com/sockenklaus/batterytracker/ui/composables/BatteryDetails.kt

@@ -1,12 +1,15 @@
 package com.sockenklaus.batterytracker.ui.composables
 
+import androidx.activity.OnBackPressedCallback
+import androidx.activity.OnBackPressedDispatcher
+import androidx.activity.compose.LocalOnBackPressedDispatcherOwner
 import androidx.compose.material.Icon
 import androidx.compose.material.IconButton
 import androidx.compose.material.Text
 import androidx.compose.material.TopAppBar
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowBack
-import androidx.compose.runtime.Composable
+import androidx.compose.runtime.*
 import androidx.navigation.NavController
 import com.sockenklaus.batterytracker.ui.Routes
 import com.sockenklaus.batterytracker.ui.models.MainViewModel
@@ -17,6 +20,14 @@ fun BatteryDetails(
     batteryId: Int? = null,
     appState: MainViewModel
 ){
+    var onBack = {
+        val backTarget = navController.previousBackStackEntry?.destination?.route ?: Routes.HOME
+        appState.currentScreen = backTarget
+        navController.navigate(backTarget)
+    }
+    
+    BackPressHandler(onBackPressed = onBack)
+
     Text(batteryId.toString())
 
 }
@@ -40,3 +51,27 @@ fun DetailsTopAppBar(
         }
     )
 }
+
+@Composable
+fun BackPressHandler(
+    backPressedDispatcher: OnBackPressedDispatcher? = LocalOnBackPressedDispatcherOwner.current?.onBackPressedDispatcher,
+    onBackPressed: () -> Unit
+) {
+    val currentOnBackPressed by rememberUpdatedState(newValue = onBackPressed)
+
+    val backCallback = remember {
+        object : OnBackPressedCallback(true) {
+            override fun handleOnBackPressed() {
+                currentOnBackPressed()
+            }
+        }
+    }
+
+    DisposableEffect(key1 = backPressedDispatcher) {
+        backPressedDispatcher?.addCallback(backCallback)
+
+        onDispose {
+            backCallback.remove()
+        }
+    }
+}