final

.idea/misc.xml

@@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="jbr-17" project-jdk-type="JavaSDK">

app/build.gradle.kts

@@ -75,6 +75,8 @@ dependencies {
     implementation("androidx.compose.ui:ui-graphics:1.6.0-beta02")
     implementation("androidx.compose.ui:ui-tooling-preview:1.6.0-beta02")
     implementation("androidx.compose.material3:material3:1.1.2")
+    implementation("androidx.compose.material:material:1.5.4")
+    implementation("androidx.paging:paging-compose:3.2.1")
 
     // Room
     val room_version = "2.6.1"

app/src/main/java/com/zyzf/coffeepreorder/database/AppContainer.kt

@@ -27,5 +27,6 @@ class AppDataContainer(private val context: Context) : AppContainer {
 
     companion object {
         const val TIMEOUT = 5000L
+        const val LIMIT = 10
     }
 }

app/src/main/java/com/zyzf/coffeepreorder/database/dao/CoffeeDao.kt

@@ -1,5 +1,6 @@
 package com.zyzf.coffeepreorder.database.dao
 
+import androidx.paging.PagingSource
 import androidx.room.Dao
 import androidx.room.Delete
 import androidx.room.Query
@@ -10,10 +11,10 @@ import kotlinx.coroutines.flow.Flow
 @Dao
 interface CoffeeDao {
     @Query("select * from coffee order by name collate nocase asc")
-    fun getAll(): Flow<List<Coffee>>
+    fun getAll(): PagingSource<Int, Coffee>
 
     @Query("select * from coffee where cart_id is not null and count > 0 order by name collate nocase asc")
-    fun getAllInCart(): Flow<List<Coffee>>
+    fun getAllInCart(): PagingSource<Int, Coffee>
 
     @Query("select sum(cost) from coffee where cart_id is not null and count > 0")
     fun getSumInCart(): Double

app/src/main/java/com/zyzf/coffeepreorder/database/model/Coffee.kt

@@ -17,7 +17,7 @@ import androidx.room.PrimaryKey
 ])
 data class Coffee(
     @PrimaryKey(autoGenerate = true)
-    val uid: Int?,
+    val uid: Int = 0,
     @ColumnInfo(name = "name")
     var name: String,
     @ColumnInfo(name = "cost")
@@ -36,7 +36,7 @@ data class Coffee(
         ingredients: String,
         cartId: Int?,
         count: Int?
-    ) : this(null, name, cost, ingredients, null, 0)
+    ) : this(0, name, cost, ingredients, null, 0)
 
     companion object {
         fun getCoffee(index: Int = 0): Coffee {

app/src/main/java/com/zyzf/coffeepreorder/database/repository/CoffeeRepository.kt

@@ -1,12 +1,13 @@
 package com.zyzf.coffeepreorder.database.repository
 
+import androidx.paging.PagingData
 import com.zyzf.coffeepreorder.database.model.Coffee
 import com.zyzf.coffeepreorder.database.model.CoffeeWithCart
 import kotlinx.coroutines.flow.Flow
 
 interface CoffeeRepository {
-    fun getAll(): Flow<List<Coffee>>
+    fun getAll(): Flow<PagingData<Coffee>>
-    fun getAllInCart(): Flow<List<Coffee>>
+    fun getAllInCart(): Flow<PagingData<Coffee>>
     fun getSumInCart(): Double
     suspend fun getByUid(uid: Int): CoffeeWithCart?
     suspend fun insert(name: String, cost: Double, ingredients: String): Long

app/src/main/java/com/zyzf/coffeepreorder/database/repository/OfflineCoffeeRepository.kt

@@ -1,13 +1,29 @@
 package com.zyzf.coffeepreorder.database.repository
 
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import com.zyzf.coffeepreorder.database.AppDataContainer
 import com.zyzf.coffeepreorder.database.dao.CoffeeDao
 import com.zyzf.coffeepreorder.database.model.Coffee
 import com.zyzf.coffeepreorder.database.model.CoffeeWithCart
 import kotlinx.coroutines.flow.Flow
 
 class OfflineCoffeeRepository(private val coffeeDao: CoffeeDao) : CoffeeRepository {
-    override fun getAll(): Flow<List<Coffee>> = coffeeDao.getAll()
+    override fun getAll(): Flow<PagingData<Coffee>> = Pager(
-    override fun getAllInCart(): Flow<List<Coffee>> = coffeeDao.getAllInCart()
+        config = PagingConfig(
+            pageSize = AppDataContainer.LIMIT,
+            enablePlaceholders = false
+        ),
+        pagingSourceFactory = coffeeDao::getAll
+    ).flow
+    override fun getAllInCart(): Flow<PagingData<Coffee>> = Pager(
+        config = PagingConfig(
+            pageSize = AppDataContainer.LIMIT,
+            enablePlaceholders = false
+        ),
+        pagingSourceFactory = coffeeDao::getAllInCart
+    ).flow
     override fun getSumInCart(): Double = coffeeDao.getSumInCart()
     override suspend fun getByUid(uid: Int): CoffeeWithCart? = coffeeDao.getByUid(uid)
     override suspend fun insert(name: String, cost: Double, ingredients: String): Long = coffeeDao.insert(name, cost, ingredients)

app/src/main/java/com/zyzf/coffeepreorder/ui/AppViewModelProvider.kt

@@ -5,6 +5,7 @@ import androidx.lifecycle.viewmodel.CreationExtras
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
 import com.zyzf.coffeepreorder.CoffeeApplication
+import com.zyzf.coffeepreorder.ui.cart.CartViewModel
 import com.zyzf.coffeepreorder.ui.coffee.CoffeeListViewModel
 
 object AppViewModelProvider {
@@ -12,6 +13,9 @@ object AppViewModelProvider {
         initializer {
             CoffeeListViewModel(coffeeApplication().container.coffeeRepository, coffeeApplication().container.cartRepository)
         }
+        initializer {
+            CartViewModel(coffeeApplication().container.coffeeRepository, coffeeApplication().container.cartRepository)
+        }
     }
 }
 

app/src/main/java/com/zyzf/coffeepreorder/ui/cart/Cart.kt

@@ -1,5 +1,6 @@
 package com.zyzf.coffeepreorder.ui.cart
 
+import android.content.Context
 import android.content.res.Configuration
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -15,24 +16,32 @@ import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.ExperimentalMaterialApi
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.Clear
+import androidx.compose.material.pullrefresh.PullRefreshIndicator
+import androidx.compose.material.pullrefresh.rememberPullRefreshState
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.ExtendedFloatingActionButton
+import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
+import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.MutableState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -43,12 +52,21 @@ import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.compose.ui.zIndex
+import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavController
+import androidx.paging.compose.LazyPagingItems
+import androidx.paging.compose.collectAsLazyPagingItems
+import androidx.paging.compose.itemContentType
+import androidx.paging.compose.itemKey
 import coil.compose.AsyncImage
 import coil.request.ImageRequest
 import com.zyzf.coffeepreorder.R
 import com.zyzf.coffeepreorder.database.AppDatabase
 import com.zyzf.coffeepreorder.database.model.Coffee
+import com.zyzf.coffeepreorder.ui.AppViewModelProvider
+import com.zyzf.coffeepreorder.ui.coffee.CoffeeList
+import com.zyzf.coffeepreorder.ui.coffee.CoffeeListViewModel
 import com.zyzf.coffeepreorder.ui.navigation.Screen
 import com.zyzf.coffeepreorder.ui.theme.CoffeePreorderTheme
 import kotlinx.coroutines.DelicateCoroutinesApi
@@ -57,88 +75,153 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
-@OptIn(DelicateCoroutinesApi::class)
+@OptIn(DelicateCoroutinesApi::class, ExperimentalMaterialApi::class)
 @Composable
-fun Cart(navController: NavController?) {
+fun Cart(
+    navController: NavController?,
+    viewModel: CartViewModel = viewModel(factory = AppViewModelProvider.Factory)
+) {
+    val coroutineScope = rememberCoroutineScope()
+    val coffeeListUiState = viewModel.coffeeListUiState.collectAsLazyPagingItems()
     val openDialog = remember { mutableStateOf(false) }
-    var coffee by remember { mutableStateOf(Coffee("", 0.0, "", null, 0)) }
+    val coffee = remember { mutableStateOf(Coffee.getCoffee()) }
-    val context = LocalContext.current
+    var refreshing by remember { mutableStateOf(false) }
-    val itemsList = remember { mutableStateListOf<Coffee>() }
+    fun refresh() = coroutineScope.launch {
-    LaunchedEffect(Unit) {
+        refreshing = true
-        withContext(Dispatchers.IO) {
+        coffeeListUiState.refresh()
-            AppDatabase.getInstance(context).coffeeDao().getAllInCart().collect { data ->
+        refreshing = false
-                itemsList.clear()
+    }
-                itemsList.addAll(data)
+    val state = rememberPullRefreshState(refreshing, ::refresh)
+    Scaffold(
+        topBar = {},
+        floatingActionButton = {
+            ExtendedFloatingActionButton(
+                onClick = { navController?.navigate(Screen.Order.route) },
+                icon = { Icon(Icons.Filled.Add, "Сделать заказ") },
+                text = { Text(text = "Сделать заказ") },
+                modifier = Modifier
+                    .padding(all = 20.dp),
+                containerColor = MaterialTheme.colorScheme.primaryContainer,
+                contentColor = MaterialTheme.colorScheme.primary
+            )
+        }
+    ) { innerPadding ->
+        PullRefreshIndicator(
+            refreshing, state,
+            Modifier
+                .zIndex(100f)
+        )
+        CartList(
+            modifier = Modifier
+                .padding(innerPadding)
+                .fillMaxSize(),
+            coffeeList = coffeeListUiState,
+            onDeleteFromCartClick = {currentCoffee: Coffee ->
+                coffee.value = currentCoffee
+                openDialog.value = true
+            }
+        )
+    }
+    DeleteFromCartAlertDialog(
+        openDialog = openDialog,
+        onConfirmClick = {
+            coroutineScope.launch {
+                viewModel.deleteCoffeeFromCart(coffee.value)
+            }
+        }
+    )
+}
+
+@Composable
+private fun CartList(
+    modifier: Modifier = Modifier,
+    coffeeList: LazyPagingItems<Coffee>,
+    onDeleteFromCartClick: (coffee: Coffee) -> Unit
+) {
+    LazyColumn(
+        horizontalAlignment = Alignment.CenterHorizontally) {
+        items(
+            count = coffeeList.itemCount,
+            key = coffeeList.itemKey(),
+            contentType = coffeeList.itemContentType()
+        ) {index ->
+            val coffee = coffeeList[index]
+            coffee?.let {
+                CartListItem(
+                    coffee = coffee,
+                    onDeleteFromCartClick = onDeleteFromCartClick
+                )
             }
         }
     }
-    LazyColumn(
+}
-        horizontalAlignment = Alignment.CenterHorizontally) {
+
-        items(itemsList) { currentCoffee ->
+@Composable
-            Row(modifier = Modifier
+private fun CartListItem (
-                .fillMaxWidth()
+    coffee: Coffee,
-                .heightIn(max = 140.dp)
+    modifier: Modifier = Modifier,
-                .padding(bottom = 10.dp, top = 10.dp),
+    onDeleteFromCartClick: (coffee: Coffee) -> Unit
-                horizontalArrangement = Arrangement.SpaceAround) {
+) {
-                AsyncImage(
+    Row(modifier = Modifier
-                    model = ImageRequest.Builder(context = LocalContext.current).data("https://zyzf.space/s/zXgFRTmbR4KMxMH/download?path=&files=coffee_image_" + currentCoffee.uid +".png")
+        .fillMaxWidth()
-                        .crossfade(true).build(),
+        .heightIn(max = 140.dp)
-                    error = painterResource(R.drawable.ic_broken_image),
+        .padding(bottom = 10.dp, top = 10.dp),
-                    placeholder = painterResource(R.drawable.loading_img),
+        horizontalArrangement = Arrangement.SpaceAround) {
-                    contentDescription = "Кофе",
+        AsyncImage(
-                    contentScale = ContentScale.Crop,
+            model = ImageRequest.Builder(context = LocalContext.current).data("https://zyzf.space/s/zXgFRTmbR4KMxMH/download?path=&files=coffee_image_" + coffee.uid +".png")
-                    modifier = Modifier
+                .crossfade(true).build(),
-                        .size(100.dp)
+            error = painterResource(R.drawable.ic_broken_image),
-                        .clip(RoundedCornerShape(50.dp))
+            placeholder = painterResource(R.drawable.loading_img),
-                )
+            contentDescription = "Кофе",
-                Column(
+            contentScale = ContentScale.Crop,
-                    Modifier
+            modifier = Modifier
-                        .weight(2f)
+                .size(100.dp)
-                        .padding(start = 20.dp)) {
+                .clip(RoundedCornerShape(50.dp))
-                    val currentCoffeeName: String = if (currentCoffee.count > 1) {
+        )
-                        currentCoffee.name + " x" + currentCoffee.count.toString()
+        Column(
-                    } else {
+            Modifier
-                        currentCoffee.name
+                .weight(2f)
-                    }
+                .padding(start = 20.dp)) {
-                    Text(text = currentCoffeeName, fontSize = 25.sp)
+            val currentCoffeeName: String = if (coffee.count > 1) {
-                    Text(text = String.format("%.2f", currentCoffee.cost), fontSize = 20.sp)
+                coffee.name + " x" + coffee.count.toString()
-                    Text(text = currentCoffee.ingredients, fontSize = 15.sp)
+            } else {
-                    Row(
+                coffee.name
-                        Modifier
+            }
-                            .fillMaxWidth()
+            Text(text = currentCoffeeName, fontSize = 25.sp)
-                            .padding(top = 5.dp)) {
+            Text(text = String.format("%.2f", coffee.cost), fontSize = 20.sp)
-                        Button(
+            Text(text = coffee.ingredients, fontSize = 15.sp)
-                            onClick = { coffee = currentCoffee; openDialog.value = true },
+            Row(
-                            shape = CircleShape,
+                Modifier
-                            modifier = Modifier.padding(start = 10.dp, end = 10.dp),
+                    .fillMaxWidth()
-                            colors = ButtonDefaults.buttonColors(
+                    .padding(top = 5.dp)) {
-                                containerColor = MaterialTheme.colorScheme.errorContainer,
+                Button(
-                                contentColor = MaterialTheme.colorScheme.error
+                    onClick = { onDeleteFromCartClick(coffee) },
-                            )
+                    shape = CircleShape,
-                        ) {
+                    modifier = Modifier.padding(start = 10.dp, end = 10.dp),
-                            Icon(
+                    colors = ButtonDefaults.buttonColors(
-                                imageVector = Icons.Default.Clear,
+                        containerColor = MaterialTheme.colorScheme.errorContainer,
-                                contentDescription = "Favorite",
+                        contentColor = MaterialTheme.colorScheme.error
-                                modifier = Modifier.size(20.dp)
+                    )
-                            )
+                ) {
-                            Spacer(Modifier.size(ButtonDefaults.IconSpacing))
+                    Icon(
-                            Text(text = "Удалить из корзины")
+                        imageVector = Icons.Default.Clear,
-                        }
+                        contentDescription = "Favorite",
-                    }
+                        modifier = Modifier.size(20.dp)
+                    )
+                    Spacer(Modifier.size(ButtonDefaults.IconSpacing))
+                    Text(text = "Удалить из корзины")
                 }
             }
         }
     }
-    Box(modifier = Modifier.fillMaxSize()) {
+}
-        ExtendedFloatingActionButton(
+
-            onClick = { navController?.navigate(Screen.Order.route) },
+@Composable
-            icon = { Icon(Icons.Filled.Add, "Сделать заказ") },
+private fun DeleteFromCartAlertDialog(
-            text = { Text(text = "Сделать заказ") },
+    modifier: Modifier = Modifier,
-            modifier = Modifier.align(alignment = Alignment.BottomEnd).padding(all = 20.dp),
+    openDialog: MutableState<Boolean>,
-            containerColor = MaterialTheme.colorScheme.primaryContainer,
+    onConfirmClick: () -> Unit
-            contentColor = MaterialTheme.colorScheme.primary
+) {
-        )
-    }
     if (openDialog.value) {
         AlertDialog(
             icon = {
@@ -156,12 +239,7 @@ fun Cart(navController: NavController?) {
             confirmButton = {
                 TextButton(
                     onClick = {
-                        GlobalScope.launch (Dispatchers.Main) {
+                        onConfirmClick()
-                            coffee.uid?.let {
-                                AppDatabase.getInstance(context).cartDao().deleteCoffee(it, 1)
-                            }
-                        }
-
                         openDialog.value = false
                     }
                 ) {

app/src/main/java/com/zyzf/coffeepreorder/ui/cart/CartViewModel.kt

@@ -0,0 +1,19 @@
+package com.zyzf.coffeepreorder.ui.cart
+
+import androidx.lifecycle.ViewModel
+import androidx.paging.PagingData
+import com.zyzf.coffeepreorder.database.model.Coffee
+import com.zyzf.coffeepreorder.database.repository.CartRepository
+import com.zyzf.coffeepreorder.database.repository.CoffeeRepository
+import kotlinx.coroutines.flow.Flow
+
+class CartViewModel(
+    private val coffeeRepository: CoffeeRepository,
+    private val cartRepository: CartRepository
+) : ViewModel() {
+    val coffeeListUiState: Flow<PagingData<Coffee>> = coffeeRepository.getAllInCart()
+
+    suspend fun deleteCoffeeFromCart(coffee: Coffee) {
+        cartRepository.deleteCoffee(coffee.uid, 1)
+    }
+}

app/src/main/java/com/zyzf/coffeepreorder/ui/coffee/CoffeeList.kt

@@ -21,12 +21,17 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.ExperimentalMaterialApi
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.outlined.Create
+import androidx.compose.material.pullrefresh.PullRefreshIndicator
+import androidx.compose.material.pullrefresh.rememberPullRefreshState
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -51,6 +56,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
+import androidx.compose.ui.Alignment.Companion.CenterHorizontally
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.layout.ContentScale
@@ -61,31 +67,46 @@ import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.compose.ui.zIndex
 import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.paging.PagingData
+import androidx.paging.compose.LazyPagingItems
+import androidx.paging.compose.collectAsLazyPagingItems
+import androidx.paging.compose.itemContentType
+import androidx.paging.compose.itemKey
 import coil.compose.AsyncImage
 import coil.request.ImageRequest
 import com.zyzf.coffeepreorder.R
 import com.zyzf.coffeepreorder.database.model.Coffee
 import com.zyzf.coffeepreorder.ui.AppViewModelProvider
 import com.zyzf.coffeepreorder.ui.theme.CoffeePreorderTheme
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.launch
 
-@OptIn(ExperimentalMaterial3Api::class)
+@OptIn(ExperimentalMaterial3Api::class, ExperimentalMaterialApi::class)
 @Composable
 fun CoffeeList(
     viewModel: CoffeeListViewModel = viewModel(factory = AppViewModelProvider.Factory)
 ) {
     val coroutineScope = rememberCoroutineScope()
-    val coffeeListUiState = viewModel.coffeeListUiState.collectAsState()
+    val coffeeListUiState = viewModel.coffeeListUiState.collectAsLazyPagingItems()
     val sheetState = rememberModalBottomSheetState()
     val openDialog = remember { mutableStateOf(false) }
     val coffee = remember { mutableStateOf(Coffee.getCoffee()) }
+    var imageUri: Any? by remember { mutableStateOf(R.drawable.img) }
+    var refreshing by remember { mutableStateOf(false) }
+    fun refresh() = coroutineScope.launch {
+        refreshing = true
+        coffeeListUiState.refresh()
+        refreshing = false
+    }
+    val state = rememberPullRefreshState(refreshing, ::refresh)
     val photoPicker = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.PickVisualMedia()
     ) {
         if (it != null) {
             Log.d("PhotoPicker", "Selected URI: $it")
-            viewModel.imageUri = it
+            imageUri = it
         } else {
             Log.d("PhotoPicker", "No media selected")
         }
@@ -111,48 +132,51 @@ fun CoffeeList(
             }
         }
     ) { innerPadding ->
-        coffeeListUiState.value.coffeeList.let {
+        PullRefreshIndicator(
-            CoffeeList(
+            refreshing, state,
-                modifier = Modifier
+            Modifier
-                    .padding(innerPadding)
+                .zIndex(100f)
-                    .fillMaxSize(),
+        )
-                coffeeList = it,
+        CoffeeList(
-                onAddToCartClick = { coffeeUid: Int ->
+            modifier = Modifier
-                    coroutineScope.launch {
+                .padding(innerPadding)
-                        viewModel.addCoffeeToCart(coffeeUid = coffeeUid)
+                .fillMaxSize(),
-                    }
+            coffeeList = coffeeListUiState,
-                },
+            onAddToCartClick = { coffeeUid: Int ->
-                onEditClick = { curcoffee: Coffee ->
-                    coroutineScope.launch {
-                        coffee.value = curcoffee
-                        openDialog.value = true
-                    }
-                }
-            )
-        }
-        AddEditModalBottomSheet(
-            coffee = coffee,
-            sheetState = sheetState,
-            openDialog = openDialog,
-            onAddClick = { coffee: Coffee, context: Context ->
                 coroutineScope.launch {
-                    viewModel.createCoffee(coffee, context)
+                    viewModel.addCoffeeToCart(coffeeUid = coffeeUid)
                 }
             },
-            onEditClick = { coffee: Coffee, context: Context ->
+            onEditClick = { curcoffee: Coffee ->
                 coroutineScope.launch {
-                    viewModel.editCoffee(coffee, context)
+                    coffee.value = curcoffee
+                    openDialog.value = true
                 }
-            },
+            }
-            onDeleteClick = { coffee: Coffee ->
-                coroutineScope.launch {
-                    viewModel.deleteCoffee(coffee)
-                }
-            },
-            photoPicker = photoPicker,
-            imageUri = viewModel.imageUri
         )
     }
+    AddEditModalBottomSheet(
+        coffee = coffee,
+        sheetState = sheetState,
+        openDialog = openDialog,
+        onAddClick = { coffee: Coffee, context: Context ->
+            coroutineScope.launch {
+                viewModel.createCoffee(coffee, imageUri as Uri, context)
+            }
+        },
+        onEditClick = { coffee: Coffee, context: Context ->
+            coroutineScope.launch {
+                viewModel.editCoffee(coffee, imageUri as Uri, context)
+            }
+        },
+        onDeleteClick = { coffee: Coffee ->
+            coroutineScope.launch {
+                viewModel.deleteCoffee(coffee)
+            }
+        },
+        photoPicker = photoPicker,
+        imageUri = imageUri
+    )
 }
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -269,14 +293,21 @@ private fun AddEditModalBottomSheet(
 @Composable
 private fun CoffeeList(
     modifier: Modifier = Modifier,
-    coffeeList: List<Coffee>,
+    coffeeList: LazyPagingItems<Coffee>,
     onAddToCartClick: (coffeeUid: Int) -> Unit,
     onEditClick: (coffee: Coffee) -> Unit
 ) {
     LazyColumn(
         horizontalAlignment = Alignment.CenterHorizontally) {
-        items(items = coffeeList, key = { it.uid!! }) { coffee ->
+        items(
-            CoffeeListItem(coffee = coffee, onAddToCartClick = onAddToCartClick, onEditClick = onEditClick)
+            count = coffeeList.itemCount,
+            key = coffeeList.itemKey(),
+            contentType = coffeeList.itemContentType()
+        ) {index ->
+            val coffee = coffeeList[index]
+            coffee?.let {
+                CoffeeListItem(coffee = coffee, onAddToCartClick = onAddToCartClick, onEditClick = onEditClick)
+            }
         }
     }
 }
@@ -319,7 +350,7 @@ private fun CoffeeListItem(
                     .padding(top = 5.dp)) {
                 Button(
                     onClick = {
-                        coffee.uid?.let { onAddToCartClick(it) }
+                        coffee.uid.let { onAddToCartClick(it) }
                     },
                     shape = CircleShape,
                     modifier = Modifier.fillMaxWidth(fraction = 0.75f)
@@ -350,6 +381,7 @@ private fun CoffeeListItem(
     }
 }
 
+
 @Preview(name = "Light Mode", showBackground = true, uiMode = Configuration.UI_MODE_NIGHT_NO)
 @Preview(name = "Dark Mode", showBackground = true, uiMode = Configuration.UI_MODE_NIGHT_YES)
 @Composable
@@ -359,7 +391,29 @@ fun CoffeeListPreview() {
             color = MaterialTheme.colorScheme.background
         ) {
             CoffeeList(
-                coffeeList = (1..20).map { i -> Coffee.getCoffee(i) },
+                coffeeList = MutableStateFlow(
+                    PagingData.from((1..20).map { i -> Coffee.getCoffee(i) })
+                ).collectAsLazyPagingItems(),
+                onAddToCartClick = {},
+                onEditClick = {}
+            )
+        }
+    }
+}
+
+
+@Preview(name = "Light Mode", showBackground = true, uiMode = Configuration.UI_MODE_NIGHT_NO)
+@Preview(name = "Dark Mode", showBackground = true, uiMode = Configuration.UI_MODE_NIGHT_YES)
+@Composable
+fun CoffeeEmptyListPreview() {
+    CoffeePreorderTheme {
+        Surface(
+            color = MaterialTheme.colorScheme.background
+        ) {
+            CoffeeList(
+                coffeeList = MutableStateFlow(
+                    PagingData.empty<Coffee>()
+                ).collectAsLazyPagingItems(),
                 onAddToCartClick = {},
                 onEditClick = {}
             )

app/src/main/java/com/zyzf/coffeepreorder/ui/coffee/CoffeeListViewModel.kt

@@ -6,24 +6,19 @@ import android.graphics.BitmapFactory
 import android.net.Uri
 import android.os.StrictMode
 import androidx.lifecycle.ViewModel
-import androidx.lifecycle.viewModelScope
+import androidx.paging.PagingData
 import com.jcraft.jsch.Channel
 import com.jcraft.jsch.ChannelSftp
 import com.jcraft.jsch.JSch
 import com.jcraft.jsch.JSchException
 import com.jcraft.jsch.Session
 import com.jcraft.jsch.SftpException
-import com.zyzf.coffeepreorder.R
-import com.zyzf.coffeepreorder.database.AppDataContainer
 import com.zyzf.coffeepreorder.database.model.Cart
 import com.zyzf.coffeepreorder.database.model.Coffee
 import com.zyzf.coffeepreorder.database.repository.CartRepository
 import com.zyzf.coffeepreorder.database.repository.CoffeeRepository
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.withContext
 import java.io.ByteArrayOutputStream
 import java.io.File
@@ -34,22 +29,15 @@ class CoffeeListViewModel(
     private val coffeeRepository: CoffeeRepository,
     private val cartRepository: CartRepository
 ) : ViewModel() {
-    val coffeeListUiState: StateFlow<CoffeeListUiState> = coffeeRepository.getAll().map {
+    val coffeeListUiState: Flow<PagingData<Coffee>> = coffeeRepository.getAll()
-        CoffeeListUiState(it)
-    }.stateIn(
-        scope = viewModelScope,
-        started = SharingStarted.WhileSubscribed(stopTimeoutMillis = AppDataContainer.TIMEOUT),
-        initialValue = CoffeeListUiState()
-    )
-    var imageUri: Any? = R.drawable.img
 
     suspend fun addCoffeeToCart(coffeeUid: Int) {
         val cart: Cart = cartRepository.get()
         cart.uid?.let { cartRepository.insertCoffee(it, coffeeUid, 1) }
     }
-    suspend fun createCoffee(coffee: Coffee, context: Context) {
+    suspend fun createCoffee(coffee: Coffee, imageUri: Uri, context: Context) {
         val newCoffee: Long = coffeeRepository.insert(coffee.name, coffee.cost, coffee.ingredients)
-        val inputStream = context.contentResolver.openInputStream(imageUri as Uri)
+        val inputStream = context.contentResolver.openInputStream(imageUri)
         val bitmap = BitmapFactory.decodeStream(inputStream)
 
         val f = File(context.cacheDir, "coffee_image_$newCoffee.png")
@@ -66,9 +54,9 @@ class CoffeeListViewModel(
 
         copyFileToSftp(f, "/mnt/nextcloud/data/Zyzf/files/Images")
     }
-    suspend fun editCoffee(coffee: Coffee, context: Context) {
+    suspend fun editCoffee(coffee: Coffee, imageUri: Uri, context: Context) {
         val editedCoffee: Int = coffeeRepository.update(coffee.uid!!, coffee.name, coffee.cost, coffee.ingredients, coffee.cartId, coffee.count)!!
-        val inputStream = context.contentResolver.openInputStream(imageUri as Uri)
+        val inputStream = context.contentResolver.openInputStream(imageUri)
         val bitmap = BitmapFactory.decodeStream(inputStream)
 
         val f = File(context.cacheDir, "coffee_image_$editedCoffee.png")
@@ -89,8 +77,6 @@ class CoffeeListViewModel(
     }
 }
 
-data class CoffeeListUiState(val coffeeList: List<Coffee> = listOf())
-
 const val REMOTE_HOST = "109.197.199.134"
 const val USERNAME = "zyzf"
 const val PASSWORD = "250303Zyzf-d-grad"