apps\store\src\main\java\cn\nfarms\store\MainActivity.kt

源码路径:apps\store\src\main\java\cn\nfarms\store\MainActivity.kt · 113 行

package cn.nfarms.store

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.isSystemInDarkTheme
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ListAlt
import androidx.compose.material.icons.filled.Receipt
import androidx.compose.material.icons.filled.ShoppingCart
import androidx.compose.material3.Badge
import androidx.compose.material3.BadgedBox
import androidx.compose.material3.Icon
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.NavigationBar
import androidx.compose.material3.NavigationBarItem
import androidx.compose.material3.Scaffold
import androidx.compose.material3.SnackbarHost
import androidx.compose.material3.SnackbarHostState
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import androidx.lifecycle.viewmodel.compose.viewModel
import cn.nfarms.core.ui.nfarmsColorScheme
import cn.nfarms.store.ui.CartScreen
import cn.nfarms.store.ui.MenuScreen
import cn.nfarms.store.ui.OrdersScreen

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        val container = (application as StoreApp).container
        setContent {
            MaterialTheme(colorScheme = nfarmsColorScheme(isSystemInDarkTheme())) {
                Surface(Modifier.fillMaxSize()) { Root(container) }
            }
        }
    }
}

enum class Tab(val label: String) { Menu("点单"), Cart("购物车"), Orders("订单") }

@Composable
private fun Root(container: Container) {
    val vm: StoreViewModel = viewModel(factory = object : ViewModelProvider.Factory {
        @Suppress("UNCHECKED_CAST")
        override fun <T : ViewModel> create(modelClass: Class<T>): T = StoreViewModel(container) as T
    })
    val ui by vm.ui.collectAsStateWithLifecycle()
    val snack = remember { SnackbarHostState() }
    var tab by remember { mutableStateOf(Tab.Menu) }

    LaunchedEffect(ui.message) {
        ui.message?.let { snack.showSnackbar(it); vm.dismissMessage() }
    }

    Scaffold(
        snackbarHost = { SnackbarHost(snack) },
        bottomBar = {
            NavigationBar {
                Tab.entries.forEach { t ->
                    NavigationBarItem(
                        selected = tab == t,
                        onClick = { tab = t },
                        icon = {
                            val badge = when (t) {
                                Tab.Cart -> ui.state.cart.sumOf { it.qty }
                                Tab.Orders -> vm.pendingCount()
                                else -> 0
                            }
                            BadgedBox(badge = {
                                if (badge > 0) Badge { Text(badge.toString()) }
                            }) {
                                Icon(
                                    when (t) {
                                        Tab.Menu -> Icons.Filled.ListAlt
                                        Tab.Cart -> Icons.Filled.ShoppingCart
                                        Tab.Orders -> Icons.Filled.Receipt
                                    },
                                    contentDescription = t.label,
                                )
                            }
                        },
                        label = { Text(t.label) },
                    )
                }
            }
        },
    ) { pad ->
        Box(Modifier.fillMaxSize().padding(pad)) {
            when (tab) {
                Tab.Menu -> MenuScreen(ui, vm)
                Tab.Cart -> CartScreen(ui, vm)
                Tab.Orders -> OrdersScreen(ui, vm)
            }
        }
    }
}