Question

我正在使用 Jetpack Compose Navigation 将 Health 实例传递给另一个可组合对象。下面的代码显示了我的健康类和我的目的地。

健康.kt：

data class Health(
    val height: Int,
    val weight: Int,
    val age: Int,
    val gender: Gender
) : Serializable

enum class Gender: Serializable { Male, Female }

NavDestination.kt

                        composable(
                            route = "result/{health}",
                            arguments = listOf(
                                navArgument("health") {
                                    type =
                                        NavType.SerializableType(Health::class.java)
                                }
                            )
                        ) { backStackEntry ->
                            val health = (backStackEntry.arguments?.getSerializable("health") as? Health) ?: return@composable
                            ResultScreen(navActions = navActions, health = health)
                        }

NavActions.kt

val navigateToResultScreen = { health: Health ->
        navController.navigate("result/{$health}")
    }

但是，根据 logcat，我收到了此错误。任何帮助将不胜感激。

 E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.octagon_technologies.bmicalculator, PID: 20788
    java.lang.UnsupportedOperationException: Serializables don't support default values.
        at androidx.navigation.NavType$SerializableType.parseValue(NavType.java:838)
        at androidx.navigation.NavType$SerializableType.parseValue(NavType.java:791)
        at androidx.navigation.NavType.parseAndPut(NavType.java:96)
        at androidx.navigation.NavDeepLink.parseArgument(NavDeepLink.java:299)
        at androidx.navigation.NavDeepLink.getMatchingArguments(NavDeepLink.java:260)
        at androidx.navigation.NavDestination.matchDeepLink(NavDestination.java:474)
        at androidx.navigation.NavGraph.matchDeepLink(NavGraph.java:79)
        at androidx.navigation.NavController.navigate(NavController.java:1034)
        at androidx.navigation.NavController.navigate(NavController.java:1017)
        at androidx.navigation.compose.NavHostControllerKt.navigate(NavHostController.kt:107)
        at androidx.navigation.compose.NavHostControllerKt.navigate$default(NavHostController.kt:106)
        at com.octagon_technologies.bmicalculator.ui.navigation.NavActions$navigateToResultScreen$1.invoke(NavActions.kt:9)
        at com.octagon_technologies.bmicalculator.ui.navigation.NavActions$navigateToResultScreen$1.invoke(NavActions.kt:8)
        at com.octagon_technologies.bmicalculator.ui.screens.home.HomeScreenKt$HomeScreen$1$6.invoke(HomeScreen.kt:122)
        at com.octagon_technologies.bmicalculator.ui.screens.home.HomeScreenKt$HomeScreen$1$6.invoke(HomeScreen.kt:120)
        at com.octagon_technologies.bmicalculator.ui.components.home.CalculateBtnKt$CalculateButton$1$1$1.invoke(CalculateBtn.kt:29)
        at com.octagon_technologies.bmicalculator.ui.components.home.CalculateBtnKt$CalculateButton$1$1$1.invoke(CalculateBtn.kt:29)

Answer 1

为什么这不起作用：https://issuetracker.google.com/issues/148523779

“Serializable 和 Parcelable 没有一致的 API 表面，允许将字符串自动解析到您的自定义类实例中。这就是 parseValue 抛出 UnsupportedOperationException 的原因。”

预计你只会在这个深层链接中传递 id，而不是完整的对象

解决方法：

composable(
    route = "result",
    arguments = listOf(
        navArgument("health") {
            type =
                NavType.SerializableType(Health::class.java)
        }
    )
) {
    val health = (navController.previousBackStackEntry.arguments?.getSerializable("health") as? Health) ?: return@composable
    ResultScreen(navActions = navActions, health = health)
}

像这样导航：

navController.currentBackStackEntry
    ?.arguments?.putSerializable("health", health)
navController.navigate("result")

UnsupportedOperationException：Serializable 不支持默认值 - Jetpack Compose Navigation

1 个答案: