import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.Button
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.viewmodel.compose.viewModel
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.launch
import androidx.lifecycle.viewModelScope
interface Repository {
suspend fun fetchItems(): List<String>
}
class FakeRepository : Repository {
override suspend fun fetchItems(): List<String> {
return listOf("Apple", "Banana", "Cherry")
}
}
class RepositoryViewModel(private val repository: Repository) : ViewModel() {
private val _data = MutableStateFlow<List<String>?>(null)
val data: StateFlow<List<String>?> = _data
fun fetchData() {
viewModelScope.launch {
_data.value = null // show loading
val items = repository.fetchItems()
_data.value = items
}
}
}
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: android.os.Bundle?) {
super.onCreate(savedInstanceState)
val repo = FakeRepository()
val factory = object : ViewModelProvider.Factory {
override fun <T : ViewModel> create(modelClass: Class<T>): T {
@Suppress("UNCHECKED_CAST")
return RepositoryViewModel(repo) as T
}
}
setContent {
MaterialTheme {
Surface(modifier = Modifier.padding(16.dp)) {
val viewModel: RepositoryViewModel = viewModel(factory = factory)
RepositoryTestScreen(viewModel)
}
}
}
}
}
@Composable
fun RepositoryTestScreen(viewModel: RepositoryViewModel) {
val data by viewModel.data.collectAsState()
Column {
Text(text = "Data:")
Text(text = data?.joinToString(", ") ?: "Loading...")
Button(onClick = { viewModel.fetchData() }, modifier = Modifier.padding(top = 16.dp)) {
Text("Fetch Data")
}
}
}This solution defines a Repository interface with a suspend function fetchItems(). The FakeRepository returns a fixed list of fruits.
The RepositoryViewModel holds a MutableStateFlow to track the data list or loading state. The fetchData() function launches a coroutine to fetch data asynchronously and update the state.
The MainActivity sets up the UI with Jetpack Compose. It creates the ViewModel with the fake repository and shows a simple screen with a Text showing "Loading..." initially or the fetched data, plus a button to trigger fetching.
This approach allows testing repository logic without real network or database, making tests fast and reliable.
