我发现在使用Navhost compose导航时,可组合屏幕会被多次重新组合
以下示例展示了如何将导航与日志集成以标识函数被调用的次数:
internal sealed class Screen(val route: String) {
object Splash : Screen("splash")
object Login : Screen("login")
object Credentials : Screen("credentials/{type}") {
fun createRoute(type: String) = "credentials/$type"
}
}
@Composable
fun HostNavGraph(
modifier: Modifier = Modifier,
startDestination: String = Splash.route,
) {
val navController = rememberNavController()
val vm: CredentialsViewModel = getViewModel()
NavHost(navController = navController, startDestination = startDestination, modifier = modifier) {
composable(route = Splash.route) {
Log.e("composable", " Splash")
SplashScreen(openLogin = {
navController.navigate(Login.route)
}, openRegistration = { type ->
navController.navigate(Credentials.createRoute(type))
})
}
composable(route = Login.route) {
Log.e("composable", " Login")
val context = LocalContext.current
LoginScreen(openRegistration = { type ->
navController.navigate(Credentials.createRoute(type))
{
popUpTo(Splash.route) { inclusive = false }
}
}, openWebView = {
openWebView(context, it)
})
}
//..
}
}
运行代码后,打开闪屏一次和登录屏幕一次后,导航的行为方式如下所示:
15:05:14 E/composable: Splash
15:05:14 E/composable: Splash
15:05:25 E/composable: Splash
15:05:25 E/composable: Login
15:05:26 E/composable: Splash
15:05:26 E/composable: Login
15:05:26 E/composable: Login
我还尝试了一些使用Navigation compose的Google示例,它表现出相同的方式,那么这是一种意图的行为吗?还是一个bug?
navigation_version = '2.4.0-alpha08'