4-ую Регистрацию починил

+ выводятся логины пользователей на карточках

app/src/main/java/com/example/myapplication/MainActivity.kt

@@ -112,14 +112,14 @@ fun AppNavigation(navController: NavHostController){
 }
 
 class GlobalUser private constructor() {
-    private var user: User? = null
+    private var user = mutableStateOf<User?>(null)
 
     fun setUser(user: User?) {
-        this.user = user
+        this.user.value = user
     }
 
     fun getUser(): User? {
-        return user
+        return user.value
     }
 
     companion object {

app/src/main/java/com/example/myapplication/database/viewmodels/UserViewModel.kt

@@ -42,8 +42,6 @@ class UserViewModel(private val userRepository: UserRepository): ViewModel() {
         val globalUser = userRepository.getUserByLogin(user.login)
         if (user.password.isNotEmpty() && user.password == globalUser?.password){
             GlobalUser.getInstance().setUser(globalUser)
-            val user123 = GlobalUser.getInstance().getUser()
-            println(user123)
         }
     }
 

app/src/main/java/com/example/myapplication/screens/authorization.kt

@@ -30,6 +30,7 @@ import androidx.compose.ui.unit.sp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavController
 import androidx.navigation.NavHostController
+import com.example.myapplication.GlobalUser
 import com.example.myapplication.R
 import com.example.myapplication.components.ActiveButton
 import com.example.myapplication.components.LoginField
@@ -50,8 +51,16 @@ import kotlinx.coroutines.withContext
 @Composable
 fun Authorization(navController: NavHostController,
                   userViewModel: UserViewModel = viewModel( factory = MobileAppViewModelProvider.Factory )){
-    val context = LocalContext.current
-    val users = userViewModel.getAllUsers.collectAsState(emptyList()).value
+
+    val message = remember { mutableStateOf("") }
+    val isAuthorizated = remember { mutableStateOf(false) }
+
+    if(GlobalUser.getInstance().getUser() != null && !isAuthorizated.value) {
+        isAuthorizated.value = !isAuthorizated.value
+        message.value = ""
+        navController.navigate("mainScreen")
+    }
+
     val login = remember { mutableStateOf("") }
     val password = remember { mutableStateOf("") }
 
@@ -71,10 +80,20 @@ fun Authorization(navController: NavHostController,
             .fillMaxWidth()
             .padding(8.dp),
             contentAlignment = Alignment.Center) {
-            Text("Продажа автомобилей",
-                fontWeight = FontWeight.Bold,
-                fontSize = 20.sp
-            )
+            Column {
+                Text("Продажа автомобилей",
+                    fontWeight = FontWeight.Bold,
+                    fontSize = 20.sp
+                )
+                if (message.value.isNotEmpty()) {
+                    Text(
+                        message.value,
+                        fontWeight = FontWeight.Bold,
+                        fontSize = 20.sp,
+                        color = Color.Red
+                    )
+                }
+            }
         }
         PlaceholderInputFieldAuth(label = "Логин", isSingleLine = true, onTextChanged = { newlogin ->
             login.value = newlogin
@@ -92,7 +111,7 @@ fun Authorization(navController: NavHostController,
                             password = password.value,
                         )
                     )
-                    navController.navigate("mainScreen")
+                    message.value = "Неправильный логин или пароль."
                 }
             })
         navButton(navController = navController, destination = "registration", label = "Регистрация",

app/src/main/java/com/example/myapplication/screens/mainScreen.kt

@@ -59,16 +59,17 @@ import com.example.myapplication.R
 import com.example.myapplication.database.MobileAppDataBase
 import com.example.myapplication.database.viewmodels.CardViewModel
 import com.example.myapplication.database.viewmodels.MobileAppViewModelProvider
+import com.example.myapplication.database.viewmodels.UserViewModel
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
 @Composable
 fun MainScreen(navController: NavHostController,
-               cardViewModel: CardViewModel = viewModel(factory = MobileAppViewModelProvider.Factory)) {
-    val context = LocalContext.current
-
+               cardViewModel: CardViewModel = viewModel(factory = MobileAppViewModelProvider.Factory),
+               userViewModel: UserViewModel = viewModel(factory = MobileAppViewModelProvider.Factory)) {
     val cards = cardViewModel.getAllCards.collectAsLazyPagingItems()
 
     Column {
@@ -89,7 +90,7 @@ fun MainScreen(navController: NavHostController,
                     ) { index: Int ->
                         val card: Card? = cards[index]
                         if (card != null) {
-                            CardListItem(item = card, navController = navController)
+                            CardListItem(item = card, navController = navController, userViewModel)
                         }
                     }
                 }
@@ -107,36 +108,18 @@ fun MainScreen(navController: NavHostController,
     }
 }
 
-@Composable
-fun <T : Any> DataListScroll(navController: NavHostController, dataList: List<T>){
-    LazyColumn(
-        horizontalAlignment = Alignment.CenterHorizontally,
-        modifier = Modifier
-            .fillMaxWidth()
-    ){
-        item {
-            when {
-                dataList.isListOf<Card>() -> addNewListItem(navController, "editcard")
-
-            }
-        }
-        items(dataList){ item ->
-            when(item){
-                is Card -> CardListItem(item = item, navController = navController)
-            }
-        }
-    }
-}
-
 inline fun <reified T> List<*>.isListOf(): Boolean {
     return isNotEmpty() && all { it is T }
 }
 
-
 @Composable
-fun CardListItem(item: Card, navController: NavHostController){
+fun CardListItem(item: Card, navController: NavHostController, userViewModel: UserViewModel){
     val context = LocalContext.current
 
+    val userLogin = remember {
+        mutableStateOf("")
+    }
+
     val showDialog = remember {
         mutableStateOf(false)
     }
@@ -145,6 +128,15 @@ fun CardListItem(item: Card, navController: NavHostController){
         mutableStateOf(false)
     }
 
+    LaunchedEffect(Unit)
+    {
+        userViewModel.getUser(item.userId).collect{
+            if (it != null) {
+                userLogin.value = it.login
+            }
+        }
+    }
+
     Card(
         modifier = Modifier
             .fillMaxWidth()
@@ -169,7 +161,7 @@ fun CardListItem(item: Card, navController: NavHostController){
                     modifier = Modifier.padding(8.dp)
                 ){
                     Text(
-                        text = "Название: ${item.name} \nРасположение: ${item.location} \nПробег: ${item.mileage} \nЦена: ${item.price}",
+                        text = "Название: ${item.name} \nРасположение: ${item.location} \nПробег: ${item.mileage} \nЦена: ${item.price} \nПродавец: ${userLogin.value}",
                         fontSize = 20.sp,
                         fontWeight = FontWeight.Bold
                     )

app/src/main/java/com/example/myapplication/screens/registration.kt

@@ -15,6 +15,7 @@ import androidx.compose.ui.unit.sp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavController
 import androidx.navigation.NavHostController
+import com.example.myapplication.GlobalUser
 import com.example.myapplication.components.ActiveButton
 import com.example.myapplication.components.LoginField
 import com.example.myapplication.components.PasswordField
@@ -31,6 +32,13 @@ import com.example.myapplication.ui.theme.SkyBlue
 fun Registration(navController: NavHostController,
                  userViewModel: UserViewModel = viewModel(
                     factory = MobileAppViewModelProvider.Factory)) {
+    val isRegistrated = remember { mutableStateOf(false) }
+
+    if(GlobalUser.getInstance().getUser() != null && !isRegistrated.value) {
+        isRegistrated.value = !isRegistrated.value
+        navController.navigate("mainScreen")
+    }
+
     val login = remember { mutableStateOf("") }
     val password = remember { mutableStateOf("") }
     val repeatepassword = remember { mutableStateOf("") }
@@ -56,7 +64,6 @@ fun Registration(navController: NavHostController,
                         )
                     )
                 }
-                navController.navigate("authorization")
             })
         navButton(navController = navController, destination = "authorization",
             label = "Назад", backgroundColor = SkyBlue, textColor = Color.Black)

app/src/main/java/com/example/myapplication/screens/user.kt

@@ -89,6 +89,10 @@ fun UserSettings(navController: NavHostController,
                         password = password.value
                     ))
                 })
+                ActiveButton(label = "Выход из аккаунта", backgroundColor = Color.Red, textColor = Color.White, onClickAction = {
+                    GlobalUser.getInstance().setUser(null)
+                    navController.navigate("authorization")
+                })
             }
         }
         Column(modifier = Modifier