ViewModel

Compose 中的 ViewModel 和状态

依赖

implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.6.1")

使用

创建数据类 GameUiState.kt

data class GameUiState(
    val currentScrambledWord: String = "",
    val isGuessedWordWrong: Boolean = false,
    val score: Int = 0,
    val currentWordCount: Int = 1,
    val isGameOver: Boolean = false
)

创建 ViewModel GameViewModel.kt

import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.lifecycle.viewmodel.compose.viewModel
// ...

@Composable
class GameViewModel : ViewModel() {
    private val _uiState = MutableStateFlow(GameUiState())
    val uiState: StateFlow<GameUiState> = _uiState.asStateFlow()

    fun updateUiState(){
        _uiState.update {
            it.copy(
                //...
            )
        }
    }
}

调用 GameScreen.kt

@Composable
fun GameScreen(
    gameViewModel: GameViewModel = viewModel()
){
    val gameUiState by gameViewModel.uiState.collectAsState() 

    //....
}