Сделал на 2 листа пагинацию, хохо

app/src/main/java/com/example/myapplication/api/ApiStatus.kt

@@ -0,0 +1,5 @@
+package com.example.myapplication.api
+
+enum class ApiStatus {
+    LOADING, ERROR, DONE
+}

app/src/main/java/com/example/myapplication/database/entities/composeui/BikeList.kt

@@ -29,6 +29,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -55,11 +56,15 @@ fun BikeList(
     currentUserViewModel: CurrentUserViewModel = viewModel(factory = AppViewModelProvider.Factory)
 ) {
     var getUser by remember { mutableStateOf(currentUserViewModel.user) }
+    val bikePagingItems = viewModel.bikePagingFlowState.flow.collectAsLazyPagingItems()
+
+    LaunchedEffect(getUser?.uid) {
+        viewModel.refresh()
+    }
 
     // Проверяем, есть ли у пользователя uid
     if (getUser?.uid != null) {
         val coroutineScope = rememberCoroutineScope()
-        val bikePagingItems = viewModel.bikeListUiState.collectAsLazyPagingItems()
 
         Scaffold(
             topBar = {},

app/src/main/java/com/example/myapplication/database/entities/composeui/BikeListViewModel.kt

@@ -1,17 +1,37 @@
 package com.example.myapplication.database.entities.composeui
 
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import androidx.paging.PagingData
+import androidx.paging.cachedIn
 import com.example.myapplication.database.entities.model.Bike
 import com.example.myapplication.database.entities.repository.BikeRepository
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.emptyFlow
 
 class BikeListViewModel(
     private val bikeRepository: BikeRepository
-) : ViewModel() {
+) : LoadingViewModel() {
-    val bikeListUiState: Flow<PagingData<Bike>> = bikeRepository.getAllBikes()
+    var bikePagingFlowState by mutableStateOf(BikePagingFlowState())
+        private set
+
+    fun refresh() {
+        runInScope(actionSuccess = {
+            val pagingSource = bikeRepository.getAllBikes()
+            bikePagingFlowState = BikePagingFlowState(pagingSource.cachedIn(viewModelScope))
+        })
+    }
 
     suspend fun deleteBike(bike: Bike) {
-        bikeRepository.deleteBike(bike)
+        runInScope(actionSuccess = {
+            bikeRepository.deleteBike(bike)
+        })
     }
 }
+
+data class BikePagingFlowState(
+    val flow: Flow<PagingData<Bike>> = emptyFlow(),
+)

app/src/main/java/com/example/myapplication/database/entities/composeui/BikeView.kt

@@ -34,6 +34,7 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavController
+import com.example.myapplication.api.ApiStatus
 import com.example.myapplication.composeui.navigation.Screen
 import com.example.myapplication.database.entities.model.Bike
 
@@ -50,7 +51,8 @@ fun BikeView(
     LaunchedEffect(Unit) {
         viewModel.refreshState()
     }
-
+    when (viewModel.apiStatus) {
+        ApiStatus.DONE -> {
     Column(
         modifier = Modifier
             .padding(16.dp)
@@ -148,3 +150,12 @@ fun BikeView(
         }
     }
 }
+
+        ApiStatus.LOADING -> LoadingPage()
+        else -> ErrorPage(
+            message = viewModel.apiError,
+            onBack = { navController.popBackStack() }
+        )
+    }
+}
+

app/src/main/java/com/example/myapplication/database/entities/composeui/BikeViewModel.kt

@@ -10,7 +10,7 @@ import com.example.myapplication.database.entities.repository.BikeRepository
 
 class BikeViewModel(
     savedStateHandle: SavedStateHandle, private val bikeRepository: BikeRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     private val bikeUid: Int = checkNotNull(savedStateHandle["id"])
 
     var bikeUiState by mutableStateOf(BikeUiState())
@@ -18,7 +18,11 @@ class BikeViewModel(
 
     suspend fun refreshState() {
         if (bikeUid > 0) {
-            bikeUiState = BikeUiState(bikeRepository.getBike(bikeUid))
+            runInScope(actionSuccess = {
+                bikeUiState = BikeUiState(bikeRepository.getBike(bikeUid))
+            }, actionError = {
+                bikeUiState = BikeUiState()
+            })
         }
     }
 

app/src/main/java/com/example/myapplication/database/entities/composeui/CartViewModel.kt

@@ -20,7 +20,7 @@ class CartViewModel(
     private val rentRepository: RentRepository,
     private val rentItemRepository: RentItemRepository,
     private val userRepository: UserRepository,
-) : ViewModel() {
+) : LoadingViewModel() {
     //private val userUid: Int = 1
     var cartUiState by mutableStateOf(CartUiState())
         private set

app/src/main/java/com/example/myapplication/database/entities/composeui/CurrentUserViewModel.kt

@@ -9,7 +9,7 @@ import com.example.myapplication.database.entities.model.User
 import com.example.myapplication.database.entities.repository.UserRepository
 import kotlinx.coroutines.launch
 
-class CurrentUserViewModel(private val userRepository: UserRepository) : ViewModel(){
+class CurrentUserViewModel(private val userRepository: UserRepository) : LoadingViewModel(){
     val argument = mutableStateOf<String?>(null)
     private val userid = mutableStateOf<Int?>(null)
     var user by mutableStateOf<User?>(null)

app/src/main/java/com/example/myapplication/database/entities/composeui/EntryUserViewModel.kt

@@ -9,7 +9,7 @@ import com.example.myapplication.database.entities.model.User
 import com.example.myapplication.database.entities.repository.UserRepository
 import kotlinx.coroutines.launch
 
-class EntryUserViewModel(private val userRepository: UserRepository) : ViewModel() {
+class EntryUserViewModel(private val userRepository: UserRepository) : LoadingViewModel() {
 
     var userList by mutableStateOf<List<User>>(emptyList())
     fun setUserList() {

app/src/main/java/com/example/myapplication/database/entities/composeui/ItemListViewModel.kt

@@ -10,7 +10,7 @@ import com.example.myapplication.database.entities.repository.UserItemRepository
 class ItemListViewModel(
     private val itemRepository: ItemRepository,
     private val userItemRepository: UserItemRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     suspend fun deleteItem(item: ItemFromBike) {
         itemRepository.deleteItem(
             Item(

app/src/main/java/com/example/myapplication/database/entities/composeui/LoadingPage.kt

@@ -0,0 +1,64 @@
+package com.example.myapplication.database.entities.composeui
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.TextUnitType
+import androidx.compose.ui.unit.dp
+import com.example.myapplication.R
+
+@Composable
+fun LoadingPage() {
+    Column(
+    modifier = Modifier
+    .fillMaxSize()
+    .padding(10.dp),
+    horizontalAlignment = Alignment.CenterHorizontally,
+    verticalArrangement = Arrangement.Center
+    ) {
+        Text(
+            modifier = Modifier.fillMaxWidth(),
+            textAlign = TextAlign.Center,
+            fontSize = TextUnit(value = 25F, type = TextUnitType.Sp),
+            text = stringResource(id = R.string.loading)
+        )
+    }
+}
+
+@Composable
+fun ErrorPage(message: String, onBack: () -> Unit) {
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .padding(10.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center
+    ) {
+        Text(
+            modifier = Modifier.fillMaxWidth(),
+            textAlign = TextAlign.Center,
+            fontSize = TextUnit(value = 20F, type = TextUnitType.Sp),
+            text = message,
+            color = Color(0xFFFF1744)
+        )
+        Spacer(modifier = Modifier.padding(bottom = 10.dp))
+        Button(
+            modifier = Modifier.fillMaxWidth(),
+            onClick = { onBack() }
+        ) {
+            Text(stringResource(id = R.string.back))
+        }
+    }
+}

app/src/main/java/com/example/myapplication/database/entities/composeui/LoadingViewModel.kt

@@ -0,0 +1,50 @@
+package com.example.myapplication.database.entities.composeui
+
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.example.myapplication.api.ApiStatus
+import kotlinx.coroutines.launch
+import retrofit2.HttpException
+import java.io.IOException
+
+open class LoadingViewModel : ViewModel() {
+    var apiStatus by mutableStateOf(ApiStatus.DONE)
+        private set
+
+    var apiError by mutableStateOf("")
+        private set
+
+    fun runInScope(
+        actionSuccess: suspend () -> Unit,
+        actionError: suspend () -> Unit,
+        needLoadingScreen: Boolean = true,
+    ) {
+        viewModelScope.launch {
+            if (needLoadingScreen)
+                apiStatus = ApiStatus.LOADING
+            runCatching {
+                actionSuccess()
+                apiStatus = ApiStatus.DONE
+                apiError = ""
+            }.onFailure { e: Throwable ->
+                when (e) {
+                    is IOException,
+                    is HttpException -> {
+                        actionError()
+                        apiStatus = ApiStatus.ERROR
+                        apiError = e.localizedMessage ?: e.toString()
+                    }
+
+                    else -> throw e
+                }
+            }
+        }
+    }
+
+    fun runInScope(actionSuccess: suspend () -> Unit) {
+        runInScope(actionSuccess, actionError = {})
+    }
+}

app/src/main/java/com/example/myapplication/database/entities/composeui/RegisterUserViewModel.kt

@@ -8,7 +8,7 @@ import com.example.myapplication.database.entities.model.User
 import com.example.myapplication.database.entities.repository.UserRepository
 import kotlinx.coroutines.launch
 
-class RegisterUserViewModel(private val userRepository: UserRepository) : ViewModel() {
+class RegisterUserViewModel(private val userRepository: UserRepository) : LoadingViewModel() {
 
     private val _users = MutableLiveData<List<User>>()
     val users: LiveData<List<User>> get() = _users

app/src/main/java/com/example/myapplication/database/entities/composeui/RentListViewModel.kt

@@ -11,7 +11,7 @@ import kotlinx.coroutines.flow.flatMapLatest
 
 class RentListViewModel(
     private val rentRepository: RentRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     private val _userId = MutableStateFlow<Int?>(null)
     val userId: StateFlow<Int?> get() = _userId
 

app/src/main/java/com/example/myapplication/database/entities/composeui/RentViewModel.kt

@@ -15,7 +15,7 @@ import kotlinx.coroutines.flow.stateIn
 class RentViewModel(
     savedStateHandle: SavedStateHandle,
     private val rentRepository: RentRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     private val rentUid: Int = checkNotNull(savedStateHandle["id"])
 
     val rentUiState: StateFlow<RentUiState> = flow{emit(rentRepository.getRent(rentUid))} .map {

app/src/main/java/com/example/myapplication/database/entities/composeui/ReportViewModel.kt

@@ -15,7 +15,7 @@ import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
 
-class ReportViewModel(private val itemRespository: RestItemRepository): ViewModel() {
+class ReportViewModel(private val itemRespository: RestItemRepository): LoadingViewModel() {
     var reportPageUiState by mutableStateOf(ReportPageUiState())
         private set
 

app/src/main/java/com/example/myapplication/database/entities/composeui/edit/BikeEdit.kt

@@ -19,7 +19,10 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavController
 import com.example.myapplication.R
+import com.example.myapplication.api.ApiStatus
 import com.example.myapplication.database.entities.composeui.AppViewModelProvider
+import com.example.myapplication.database.entities.composeui.ErrorPage
+import com.example.myapplication.database.entities.composeui.LoadingPage
 import com.example.myapplication.ui.theme.PmudemoTheme
 import kotlinx.coroutines.launch
 
@@ -29,7 +32,8 @@ fun BikeEdit(
     viewModel: BikeEditViewModel = viewModel(factory = AppViewModelProvider.Factory),
 ) {
     val coroutineScope = rememberCoroutineScope()
-
+    when (viewModel.apiStatus) {
+        ApiStatus.DONE -> {
     BikeEdit(
         bikeUiState = viewModel.bikeUiState,
         onClick = {
@@ -40,6 +44,13 @@ fun BikeEdit(
         },
         onUpdate = viewModel::updateUiState,
     )
+        }
+        ApiStatus.LOADING -> LoadingPage()
+        else -> ErrorPage(
+            message = viewModel.apiError,
+            onBack = { navController.popBackStack() }
+        )
+    }
 }
 
 @Composable

app/src/main/java/com/example/myapplication/database/entities/composeui/edit/BikeEditViewModel.kt

@@ -6,6 +6,7 @@ import androidx.compose.runtime.setValue
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.example.myapplication.database.entities.composeui.LoadingViewModel
 import com.example.myapplication.database.entities.model.Bike
 import com.example.myapplication.database.entities.model.BikeWithItems
 import com.example.myapplication.database.entities.model.ItemFromBike
@@ -15,7 +16,7 @@ import kotlinx.coroutines.launch
 class BikeEditViewModel(
     savedStateHandle: SavedStateHandle,
     private val bikeRepository: BikeRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     var bikeUiState by mutableStateOf(BikeUiState())
         private set
 
@@ -23,10 +24,15 @@ class BikeEditViewModel(
 
     init {
         viewModelScope.launch {
-            if (bikeUid > 0) {
+            runInScope(
-                bikeUiState = bikeRepository.getBike(bikeUid)
+                actionSuccess = {
-                    .toUiState(true)
+                    bikeUiState = bikeRepository.getBike(bikeUid)
-            }
+                        .toUiState(true)
+                },
+                actionError = {
+                    bikeUiState = BikeUiState()
+                }
+            )
         }
     }
 
@@ -39,11 +45,15 @@ class BikeEditViewModel(
 
     suspend fun saveBike() {
         if (validateInput()) {
-            if (bikeUid > 0) {
+            runInScope(
-                bikeRepository.updateBike(bikeUiState.bikeDetails.toBike(bikeUid))
+                actionSuccess = {
-            } else {
+                    if (bikeUid > 0) {
-                bikeRepository.insertBike(bikeUiState.bikeDetails.toBike())
+                        bikeRepository.updateBike(bikeUiState.bikeDetails.toBike(bikeUid))
-            }
+                    } else {
+                        bikeRepository.insertBike(bikeUiState.bikeDetails.toBike())
+                    }
+                }
+            )
         }
     }
 

app/src/main/java/com/example/myapplication/database/entities/composeui/edit/ItemEditViewModel.kt

@@ -6,6 +6,7 @@ import androidx.compose.runtime.setValue
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.example.myapplication.database.entities.composeui.LoadingViewModel
 import com.example.myapplication.database.entities.model.Item
 import com.example.myapplication.database.entities.repository.ItemRepository
 import kotlinx.coroutines.launch
@@ -14,7 +15,7 @@ import org.threeten.bp.LocalDateTime
 class ItemEditViewModel(
     savedStateHandle: SavedStateHandle,
     private val itemRepository: ItemRepository
-) : ViewModel() {
+) : LoadingViewModel() {
     var itemUiState by mutableStateOf(ItemUiState())
         private set
 

app/src/main/res/values/strings.xml

@@ -21,4 +21,6 @@
     <string name="item_bike_not_select">Велосипед не указан</string>
     <string name="size">Размер загруженного изображения: %1$dx%2$d</string>
     <string name="not_uploaded">Загрузите изображение</string>
+    <string name="loading">Загрузка…</string>
+    <string name="back">Назад</string>
 </resources>