Minor adjustment to input validation and initial message showing delay

E13RoomShoppingList/app/src/main/java/com/example/e13roomshoppinglist/MainActivity.kt

 package com.example.e13roomshoppinglist
 
+import android.annotation.SuppressLint
 import android.os.Bundle
 import android.widget.Toast
 import androidx.activity.ComponentActivity
@@ -12,6 +13,7 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
@@ -19,6 +21,10 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.room.Room
 import com.example.e13roomshoppinglist.ui.theme.E13RoomShoppingListTheme
+import kotlinx.coroutines.DelicateCoroutinesApi
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
 
 class MainActivity : ComponentActivity() {
     private val db by lazy {
@@ -36,6 +42,8 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    @OptIn(DelicateCoroutinesApi::class)
+    @SuppressLint("CoroutineCreationDuringComposition")
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
@@ -43,10 +51,14 @@ class MainActivity : ComponentActivity() {
                 val state by viewModel.state.collectAsState()
                 val ctx = LocalContext.current
                 var toast by remember {
-                    mutableStateOf<Toast?>(Toast.makeText(ctx, "Loaded data from room db!", Toast.LENGTH_SHORT))
+                    mutableStateOf<Toast?>(null)
+                }
+                var isDataLoadMsgShown by rememberSaveable {
+                    mutableStateOf(false)
                 }
 
                 val showToast = { msg: String ->
+                    toast?.cancel()
                     toast = Toast.makeText(ctx, msg, Toast.LENGTH_SHORT)
                     toast?.show()
                 }
@@ -55,7 +67,25 @@ class MainActivity : ComponentActivity() {
                     modifier = Modifier.fillMaxSize(),
                     color = MaterialTheme.colorScheme.background
                 ) {
-                    ShoppingListScreen(state = state, onEvent = viewModel::onEvent, onShowToast = showToast)
+                    ShoppingListScreen(
+                        state = state,
+                        onEvent = viewModel::onEvent,
+                        onShowToast = showToast
+                    )
+                    if (!isDataLoadMsgShown) {
+                        GlobalScope.launch {
+                            delay(2000)
+                            runOnUiThread {
+                                val itemCount = state.shoppingListItems.count()
+                                if (itemCount == 0) {
+                                    showToast("Database is empty!")
+                                } else {
+                                    showToast("Loaded $itemCount item${if (itemCount==1) "" else "s"} from database!")
+                                }
+                                isDataLoadMsgShown = true
+                            }
+                        }
+                    }
                 }
             }
         }

E13RoomShoppingList/app/src/main/java/com/example/e13roomshoppinglist/ShoppingListDatabase.kt

@@ -38,7 +38,7 @@ data class ShoppingListItem(
 @Dao
 interface ShoppingListDao{
     @Upsert
-    fun upsertShoppingListItem(shoppingListItem: ShoppingListItem)
+    suspend fun upsertShoppingListItem(shoppingListItem: ShoppingListItem)
 
     @Delete
     suspend fun deleteShoppingListItem(shoppingListItem: ShoppingListItem)

E13RoomShoppingList/app/src/main/java/com/example/e13roomshoppinglist/ShoppingListScreen.kt

 package com.example.e13roomshoppinglist
 
 
-import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.layout.Arrangement
@@ -10,7 +9,6 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
@@ -124,6 +122,7 @@ fun ShoppingListScreen(
                             )
                         }
                     }
+                    Divider(thickness = 1.dp, color = Color.LightGray)
                 }
                 item {
                     Row(
@@ -132,7 +131,7 @@ fun ShoppingListScreen(
                             .height(70.dp),
                         verticalAlignment = Alignment.CenterVertically
                     ) {
-                        Text(text = "Empty item to fill up room so that the last item does not go under FAB.", fontSize = 12.sp, color = Color.Gray)
+                        Text(text = "Empty item to fill up room so that the last item's edit and delete button does not go under FAB.", fontSize = 12.sp, color = Color.Gray)
                     }
                 }
             }
@@ -168,35 +167,26 @@ fun AddShoppingListItemDialog(
                     placeholder = { Text(text = "Item Name") },
                 )
                 TextField(
-                    value = if(shoppingListItem.count>0) shoppingListItem.count.toString() else "",
+                    value = shoppingListItem.count,
                     label = { Text(text = "Count") },
                     placeholder = { Text(text = "Count") },
                     onValueChange = {
-                        var count = it.toIntOrNull()
-                        if (count===null) {
-                            onShowToast("Invalid value for Count!")
-                            count = 0
-                        }
-                        onEvent(ShoppingListEvent.SetCount(count = count))
+                        onEvent(ShoppingListEvent.SetCount(count = it))
                     },
                     keyboardOptions = KeyboardOptions().copy(
                         autoCorrect = false,
-                        keyboardType = KeyboardType.Number
+                        keyboardType = KeyboardType.NumberPassword
                     ),
                     leadingIcon = {
                         Text(text = "🧮", fontSize = 24.sp)
                     }
                 )
                 TextField(
-                    value = if(shoppingListItem.price>0) shoppingListItem.price.toString() else "",
+                    value = shoppingListItem.price,
                     label = { Text(text = "Price") },
                     placeholder = { Text(text = "Price") },
                     onValueChange = {
-                        var price = it.toFloatOrNull()
-                        if (price===null) {
-                            price = 0f
-                        }
-                        onEvent(ShoppingListEvent.SetPrice(price = price))
+                        onEvent(ShoppingListEvent.SetPrice(price = it))
                     },
                     keyboardOptions = KeyboardOptions().copy(
                         autoCorrect = false,
@@ -211,13 +201,22 @@ fun AddShoppingListItemDialog(
         confirmButton = {
             Button(onClick = {
                 if (state.newShoppingListItem.name.length<3){
-                    onShowToast("Item name should not be too short!")
+                    onShowToast("Item Name is too short!")
+                    return@Button
+                }
+                if (state.newShoppingListItem.count.toIntOrNull()===null){
+                    onShowToast("Invalid value for Count! Failed to convert value to Int.")
                     return@Button
                 }
+                if (state.newShoppingListItem.price.toFloatOrNull()===null){
+                    onShowToast("Invalid value for Price! Failed to convert value to Float.")
+                    return@Button
+                }
+
                 if (state.isAddingNewShoppingListItem) {
                     onEvent(ShoppingListEvent.InsertNewShoppingListItemToDb).also { onShowToast("Added new item to shopping list!") }
                 } else if (state.isEditingShoppingListItem) {
-                    onEvent(ShoppingListEvent.UpdateCurrentlyEditingShoppingListItem).also { onShowToast("Updated shopping list item!") }
+                    onEvent(ShoppingListEvent.UpdateCurrentlyEditingShoppingListItem).also { onShowToast("Updated shopping list item ${state.currentlyEditingShoppingListItem?.name}!") }
                 }
             }) {
                 Text(text = if (state.isEditingShoppingListItem) "Update" else "Insert")

E13RoomShoppingList/app/src/main/java/com/example/e13roomshoppinglist/ShoppingListViewModel.kt

@@ -28,8 +28,8 @@ sealed interface ShoppingListEvent{
     data object OpenAddingNewShoppingListItemDialog: ShoppingListEvent
     data object CloseAddingNewShoppingListItemDialog: ShoppingListEvent
     data class SetName(val name: String): ShoppingListEvent
-    data class SetPrice(val price: Float): ShoppingListEvent
-    data class SetCount(val count: Int): ShoppingListEvent
+    data class SetPrice(val price: String): ShoppingListEvent
+    data class SetCount(val count: String): ShoppingListEvent
     data object InsertNewShoppingListItemToDb: ShoppingListEvent
 
     data class OpenEditingShoppingListItem(val shoppingListItem: ShoppingListItem): ShoppingListEvent
@@ -42,8 +42,8 @@ sealed interface ShoppingListEvent{
 
 data class NewShoppingListItem(
     val name: String = "",
-    val price: Float = 0f,
-    val count: Int = 0
+    val price: String = "",
+    val count: String = ""
 )
 
 data class ShoppingListState(
@@ -103,12 +103,16 @@ class ShoppingListViewModel(private val dao: ShoppingListDao): ViewModel() {
             ShoppingListEvent.InsertNewShoppingListItemToDb -> {
                 val newShoppingListItem = _state.value.newShoppingListItem
                 GlobalScope.launch {
+                    val price = newShoppingListItem.price.toFloatOrNull()
+                    val count = newShoppingListItem.count.toIntOrNull()
+                    if (price===null || count===null) return@launch
+
                     dao.upsertShoppingListItem(ShoppingListItem(
                         name = newShoppingListItem.name,
-                        price = newShoppingListItem.price,
-                        count = newShoppingListItem.count))
+                        price = price,
+                        count = count))
                 }
-                _state.update { it.copy(newShoppingListItem=NewShoppingListItem()) }
+                _state.update { it.copy(newShoppingListItem= NewShoppingListItem()) }
             }
             ShoppingListEvent.CloseAddingNewShoppingListItemDialog -> {
                 _state.update { it.copy(isAddingNewShoppingListItem = false) }
@@ -117,13 +121,14 @@ class ShoppingListViewModel(private val dao: ShoppingListDao): ViewModel() {
             is ShoppingListEvent.OpenEditingShoppingListItem -> {
                 _state.update {
                     val shoppingListItem = event.shoppingListItem
+
                     it.copy(
                     isEditingShoppingListItem = true,
                     currentlyEditingShoppingListItem = shoppingListItem,
                     newShoppingListItem = NewShoppingListItem(
                         name = shoppingListItem.name,
-                        price = shoppingListItem.price,
-                        count = shoppingListItem.count
+                        price = shoppingListItem.price.toString(),
+                        count = shoppingListItem.count.toString()
                     ))
                 }
             }
@@ -131,10 +136,14 @@ class ShoppingListViewModel(private val dao: ShoppingListDao): ViewModel() {
                 val currentlyEditingShoppingListItem = _state.value.currentlyEditingShoppingListItem
                 if (currentlyEditingShoppingListItem===null) return
                 val modifiedShoppingListItemAttrs = _state.value.newShoppingListItem
+                val price = modifiedShoppingListItemAttrs.price.toFloatOrNull()
+                val count = modifiedShoppingListItemAttrs.count.toIntOrNull()
+                if (price===null || count===null) return
+
                 val updatedShoppingListItem = currentlyEditingShoppingListItem.copy(
                     name = modifiedShoppingListItemAttrs.name,
-                    price = modifiedShoppingListItemAttrs.price,
-                    count = modifiedShoppingListItemAttrs.count
+                    price = price,
+                    count = count
                 )
 
                 GlobalScope.launch { dao.upsertShoppingListItem(updatedShoppingListItem) }