Feat : add navigation to app

app/src/main/java/com/example/cupcake/CupcakeScreen.kt

@@ -15,6 +15,12 @@
  */
 package com.example.cupcake
 
+import android.content.Context
+import android.content.Intent
+import androidx.annotation.StringRes
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowBack
 import androidx.compose.material3.Icon
@@ -28,23 +34,40 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.dimensionResource
 import androidx.compose.ui.res.stringResource
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavHostController
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.rememberNavController
+import com.example.cupcake.data.DataSource
+import com.example.cupcake.ui.OrderSummaryScreen
 import com.example.cupcake.ui.OrderViewModel
+import com.example.cupcake.ui.SelectOptionScreen
+import com.example.cupcake.ui.StartOrderScreen
 
 /**
  * Composable that displays the topBar and displays back button if back navigation is possible.
  */
+enum class CupcakeScreen(@StringRes val title: Int) {
+    Start(title = R.string.app_name),
+    Flavor(title = R.string.choose_flavor),
+    Pickup(title = R.string.choose_pickup_date),
+    Summary(title = R.string.order_summary)
+}
+
 @Composable
 fun CupcakeAppBar(
+    currentScreen: CupcakeScreen,
     canNavigateBack: Boolean,
     navigateUp: () -> Unit,
     modifier: Modifier = Modifier
 ) {
     TopAppBar(
-        title = { Text(stringResource(id = R.string.app_name)) },
+        title = { Text(stringResource(id = currentScreen.title)) },
         colors = TopAppBarDefaults.mediumTopAppBarColors(
             containerColor = MaterialTheme.colorScheme.primaryContainer
         ),
@@ -67,16 +90,94 @@ fun CupcakeApp(
     viewModel: OrderViewModel = viewModel(),
     navController: NavHostController = rememberNavController()
 ) {
+    val backStackEntry by navController.currentBackStackEntryAsState()
+    val currentScreen = CupcakeScreen.valueOf(
+        backStackEntry?.destination?.route ?: CupcakeScreen.Start.name
+    )
 
     Scaffold(
         topBar = {
             CupcakeAppBar(
-                canNavigateBack = false,
-                navigateUp = { /* TODO: implement back navigation */ }
+                canNavigateBack = navController.previousBackStackEntry != null,
+                navigateUp = {navController.navigateUp() },
+                currentScreen = currentScreen
             )
         }
     ) { innerPadding ->
         val uiState by viewModel.uiState.collectAsState()
+        NavHost(
+            navController = navController,
+            startDestination = CupcakeScreen.Start.name,
+            modifier = Modifier.padding(innerPadding)
+        ) {
+            composable(CupcakeScreen.Start.name) {
+                StartOrderScreen(
+                    quantityOptions = DataSource.quantityOptions,
+                    onNextButtonClicked = {
+                        viewModel.setQuantity(it)
+                        navController.navigate(CupcakeScreen.Flavor.name)
+                    },
+                    modifier = Modifier
+                        .fillMaxSize()
+                        .padding(dimensionResource(id = R.dimen.padding_medium))
+                )
+            }
+            composable(CupcakeScreen.Flavor.name) {
+                val context = LocalContext.current
+                SelectOptionScreen(
+                    subtotal = uiState.price,
+                    onNextButtonClicked = { navController.navigate(CupcakeScreen.Pickup.name) },
+                    options = DataSource.flavors.map{context.resources.getString(it)},
+                    onCancelButtonClicked = { cancelOrderAndBackToStart(navController, viewModel) },
+                    onSelectionChanged = { flavor ->
+                        viewModel.setFlavor(flavor)
+                    },
+                    modifier = Modifier
+                        .fillMaxHeight()
+                )
+            }
+            composable(CupcakeScreen.Pickup.name) {
+                SelectOptionScreen(
+                    subtotal = uiState.price,
+                    options = uiState.pickupOptions,
+                    onCancelButtonClicked = { cancelOrderAndBackToStart(navController, viewModel) },
+                    onNextButtonClicked = { navController.navigate(CupcakeScreen.Summary.name) },
+                    onSelectionChanged = {viewModel.setDate(it)},
+                    modifier = Modifier.fillMaxHeight()
+                )
+            }
+            composable(CupcakeScreen.Summary.name) {
+                val context = LocalContext.current
+                OrderSummaryScreen(
+                    orderUiState = uiState,
+                    modifier = Modifier.fillMaxHeight(),
+                    onCancelButtonClicked = { cancelOrderAndBackToStart(navController, viewModel) },
+                    onSendButtonClicked = { subject, summary->
+                        shareOrder(context,summary,subject)
+                        navController.navigate(CupcakeScreen.Start.name)
+                    }
+                )
+            }
+        }
+    }
+}
 
+private fun cancelOrderAndBackToStart(navController: NavHostController, viewModel: OrderViewModel) {
+    viewModel.resetOrder()
+    navController.popBackStack(CupcakeScreen.Start.name,false)
+}
+
+private fun shareOrder(context: Context,summary:String,subject:String){
+    val intent = Intent(Intent.ACTION_SEND).apply {
+        type = "text/plain"
+        putExtra(Intent.EXTRA_TEXT, summary)
+        putExtra(Intent.EXTRA_SUBJECT, subject)
     }
+    context.startActivity(
+        Intent.createChooser(
+            intent,
+            context.getString(R.string.new_cupcake_order)
+        )
+    )
 }
+

app/src/main/java/com/example/cupcake/ui/SelectOptionScreen.kt

@@ -52,6 +52,8 @@ fun SelectOptionScreen(
     subtotal: String,
     options: List<String>,
     onSelectionChanged: (String) -> Unit = {},
+    onCancelButtonClicked: () -> Unit = {},
+    onNextButtonClicked: () -> Unit = {},
     modifier: Modifier = Modifier
 ) {
     var selectedValue by rememberSaveable { mutableStateOf("") }
@@ -105,15 +107,17 @@ fun SelectOptionScreen(
         ) {
             OutlinedButton(
                 modifier = Modifier.weight(1f),
-                onClick = {}
+                onClick = {onCancelButtonClicked()}
             ) {
                 Text(stringResource(R.string.cancel))
             }
             Button(
                 modifier = Modifier.weight(1f),
                 // the button is enabled when the user makes a selection
                 enabled = selectedValue.isNotEmpty(),
-                onClick = {}
+                onClick = {
+                    onNextButtonClicked()
+                }
             ) {
                 Text(stringResource(R.string.next))
             }

app/src/main/java/com/example/cupcake/ui/StartOrderScreen.kt

@@ -49,6 +49,7 @@ import com.example.cupcake.ui.theme.CupcakeTheme
 @Composable
 fun StartOrderScreen(
     quantityOptions: List<Pair<Int, Int>>,
+    onNextButtonClicked: (Int) -> Unit,
     modifier: Modifier = Modifier
 ) {
     Column(
@@ -83,7 +84,9 @@ fun StartOrderScreen(
             quantityOptions.forEach { item ->
                 SelectQuantityButton(
                     labelResourceId = item.first,
-                    onClick = {}
+                    onClick = {
+                            onNextButtonClicked(item.second)
+                    }
                 )
             }
         }
@@ -114,6 +117,7 @@ fun StartOrderPreview() {
     CupcakeTheme {
         StartOrderScreen(
             quantityOptions = DataSource.quantityOptions,
+            onNextButtonClicked = {},
             modifier = Modifier
                 .fillMaxSize()
                 .padding(dimensionResource(R.dimen.padding_medium))

app/src/main/java/com/example/cupcake/ui/SummaryScreen.kt

@@ -48,6 +48,8 @@ import com.example.cupcake.ui.theme.CupcakeTheme
 @Composable
 fun OrderSummaryScreen(
     orderUiState: OrderUiState,
+    onCancelButtonClicked: () -> Unit = {},
+    onSendButtonClicked: (String,String) -> Unit,
     modifier: Modifier = Modifier
 ) {
     val resources = LocalContext.current.resources
@@ -103,13 +105,13 @@ fun OrderSummaryScreen(
             ) {
                 Button(
                     modifier = Modifier.fillMaxWidth(),
-                    onClick = {}
+                    onClick = {onSendButtonClicked(newOrder, orderSummary)}
                 ) {
                     Text(stringResource(R.string.send))
                 }
                 OutlinedButton(
                     modifier = Modifier.fillMaxWidth(),
-                    onClick = {}
+                    onClick = {onCancelButtonClicked()}
                 ) {
                     Text(stringResource(R.string.cancel))
                 }
@@ -124,6 +126,7 @@ fun OrderSummaryPreview() {
     CupcakeTheme {
         OrderSummaryScreen(
             orderUiState = OrderUiState(0, "Test", "Test", "$300.00"),
+            onSendButtonClicked = { _: String, _: String ->},
             modifier = Modifier.fillMaxHeight()
         )
     }