commit f4cbea5b6c7ffec7cd1d69adee6a3173953d29bd
Author: nabilasuwandira <202310715066@mhs.ubharajaya.ac.id>
Date:   Fri Nov 7 13:31:21 2025 +0700

    ppp

diff --git a/app/src/main/java/com/example/kalkulatorbmi/MainScreen.kt b/app/src/main/java/com/example/kalkulatorbmi/MainScreen.kt
new file mode 100644
index 0000000..cdbb7d2
--- /dev/null
+++ b/app/src/main/java/com/example/kalkulatorbmi/MainScreen.kt
@@ -0,0 +1,209 @@
+package com.example.kalkulatorbmi
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.slideInVertically
+import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.*
+import androidx.compose.material3.*
+import androidx.compose.runtime.*
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalFocusManager
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.navigation.NavController
+import kotlin.math.pow
+
+// Enum untuk merepresentasikan sistem unit yang dipilih
+enum class UnitSystem {
+    Metric, USC
+}
+
+@Composable
+fun MainScreen(navController: NavController) {
+    // --- STATE UNTUK SEMUA FITUR ---
+    var unitSystem by remember { mutableStateOf(UnitSystem.Metric) }
+    var umur by remember { mutableStateOf("") }
+    var jenisKelamin by remember { mutableStateOf<String?>(null) }
+
+    // State untuk Metric
+    var tinggiCm by remember { mutableStateOf("") }
+    var beratKg by remember { mutableStateOf("") }
+
+    // State untuk USC
+    var tinggiFt by remember { mutableStateOf("") }
+    var tinggiIn by remember { mutableStateOf("") }
+    var beratLbs by remember { mutableStateOf("") }
+
+    var bmiResult by remember { mutableStateOf<Float?>(null) }
+    var bmiCategory by remember { mutableStateOf("") }
+
+    // Variabel Warna dari Tema
+    val surfaceVariantColor = MaterialTheme.colorScheme.surfaceVariant
+    val errorColor = MaterialTheme.colorScheme.error
+    val errorContainerColor = MaterialTheme.colorScheme.errorContainer
+    val primaryColor = MaterialTheme.colorScheme.primary
+    val backgroundColor = MaterialTheme.colorScheme.background
+    val onBackgroundColor = MaterialTheme.colorScheme.onBackground
+    val secondaryColor = MaterialTheme.colorScheme.secondary
+
+    var bmiColor by remember { mutableStateOf(surfaceVariantColor) }
+    val focusManager = LocalFocusManager.current
+
+    fun calculateBmi() {
+        focusManager.clearFocus()
+        var bmi: Float? = null
+
+        if (unitSystem == UnitSystem.Metric) {
+            val tinggiCmFloat = tinggiCm.toFloatOrNull()
+            val beratKgFloat = beratKg.toFloatOrNull()
+            if (tinggiCmFloat != null && beratKgFloat != null && tinggiCmFloat > 0) {
+                val tinggiM = tinggiCmFloat / 100
+                bmi = beratKgFloat / tinggiM.pow(2)
+            }
+        } else { // USC
+            val tinggiFtFloat = tinggiFt.toFloatOrNull() ?: 0f
+            val tinggiInFloat = tinggiIn.toFloatOrNull() ?: 0f
+            val beratLbsFloat = beratLbs.toFloatOrNull()
+            if (beratLbsFloat != null && (tinggiFtFloat > 0 || tinggiInFloat > 0)) {
+                val totalTinggiInches = (tinggiFtFloat * 12) + tinggiInFloat
+                bmi = (beratLbsFloat / totalTinggiInches.pow(2)) * 703
+            }
+        }
+
+        if (bmi != null && umur.isNotBlank() && jenisKelamin != null) {
+            bmiResult = bmi
+            bmiCategory = when {
+                bmi < 18.5 -> {
+                    bmiColor = errorColor; "Berat badan kurang"
+                }
+                bmi < 25 -> {
+                    bmiColor = Color(0xFF4CAF50); "Berat badan normal"
+                }
+                bmi < 30 -> {
+                    bmiColor = Color(0xFFFFC107); "Kelebihan berat badan"
+                }
+                else -> {
+                    bmiColor = errorContainerColor; "Obesitas"
+                }
+            }
+        }
+    }
+
+    fun reset() {
+        umur = ""; jenisKelamin = null; tinggiCm = ""; beratKg = ""
+        tinggiFt = ""; tinggiIn = ""; beratLbs = ""
+        bmiResult = null; bmiCategory = ""; bmiColor = surfaceVariantColor
+    }
+
+    val gradientBrush = Brush.verticalGradient(
+        colors = listOf(primaryColor.copy(alpha = 0.2f), backgroundColor)
+    )
+
+    Box(modifier = Modifier.fillMaxSize().background(gradientBrush)) {
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(16.dp)
+                .verticalScroll(rememberScrollState()), // Membuat Column bisa di-scroll
+            horizontalAlignment = Alignment.CenterHorizontally
+        ) {
+            Text(
+                "Kalkulator BMI",
+                style = MaterialTheme.typography.headlineLarge,
+                color = onBackgroundColor
+            )
+
+            // --- UI UNTUK PILIHAN UNIT SYSTEM ---
+            Row(
+                modifier = Modifier.fillMaxWidth().padding(vertical = 16.dp),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.Center
+            ) {
+                Text("Metric (kg, cm)", color = if (unitSystem == UnitSystem.Metric) primaryColor else onBackgroundColor)
+                Spacer(Modifier.width(8.dp))
+                Switch(
+                    checked = unitSystem == UnitSystem.USC,
+                    onCheckedChange = {
+                        unitSystem = if (it) UnitSystem.USC else UnitSystem.Metric
+                    }
+                )
+                Spacer(Modifier.width(8.dp))
+                Text("USC (lbs, ft, in)", color = if (unitSystem == UnitSystem.USC) primaryColor else onBackgroundColor)
+            }
+
+            Card(
+                shape = RoundedCornerShape(16.dp),
+                elevation = CardDefaults.cardElevation(8.dp),
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                Column(modifier = Modifier.padding(16.dp)) {
+                    // --- Pilihan Jenis Kelamin (Tetap Sama) ---
+                    Text("Jenis Kelamin", style = MaterialTheme.typography.bodyLarge, modifier = Modifier.padding(bottom = 8.dp))
+                    // (Kode Row untuk jenis kelamin tidak berubah, jadi disingkat untuk kejelasan)
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.spacedBy(16.dp)
+                    ) {
+                        val isLakiSelected = jenisKelamin == "Laki-laki"
+                        Button(onClick={jenisKelamin="Laki-laki"},modifier=Modifier.weight(1f),colors=ButtonDefaults.buttonColors(containerColor=if(isLakiSelected)primaryColor else MaterialTheme.colorScheme.surface,contentColor=if(isLakiSelected)MaterialTheme.colorScheme.onPrimary else MaterialTheme.colorScheme.onSurface),border=BorderStroke(1.dp,if(isLakiSelected)primaryColor else MaterialTheme.colorScheme.outline)){Icon(Icons.Default.Male,"Laki-laki",modifier=Modifier.size(18.dp));Spacer(Modifier.width(8.dp));Text("Laki-laki")}
+                        val isPerempuanSelected = jenisKelamin == "Perempuan"
+                        Button(onClick={jenisKelamin="Perempuan"},modifier=Modifier.weight(1f),colors=ButtonDefaults.buttonColors(containerColor=if(isPerempuanSelected)primaryColor else MaterialTheme.colorScheme.surface,contentColor=if(isPerempuanSelected)MaterialTheme.colorScheme.onPrimary else MaterialTheme.colorScheme.onSurface),border=BorderStroke(1.dp,if(isPerempuanSelected)primaryColor else MaterialTheme.colorScheme.outline)){Icon(Icons.Default.Female,"Perempuan",modifier=Modifier.size(18.dp));Spacer(Modifier.width(8.dp));Text("Perempuan")}
+                    }
+
+                    Spacer(modifier = Modifier.height(16.dp))
+                    OutlinedTextField(value=umur,onValueChange={umur=it},label={Text("Umur")},leadingIcon={Icon(Icons.Default.CalendarToday,"Umur")},keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Next),singleLine=true,modifier=Modifier.fillMaxWidth())
+                    Spacer(modifier = Modifier.height(16.dp))
+
+                    // --- INPUT FIELD DINAMIS BERDASARKAN UNIT SYSTEM ---
+                    if (unitSystem == UnitSystem.Metric) {
+                        // Input untuk METRIC
+                        OutlinedTextField(value=tinggiCm,onValueChange={tinggiCm=it},label={Text("Tinggi Badan (cm)")},leadingIcon={Icon(Icons.Default.Height,"Tinggi Badan")},keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Next),singleLine=true,modifier=Modifier.fillMaxWidth())
+                        Spacer(modifier = Modifier.height(16.dp))
+                        OutlinedTextField(value=beratKg,onValueChange={beratKg=it},label={Text("Berat Badan (kg)")},leadingIcon={Icon(Icons.Default.MonitorWeight,"Berat Badan")},keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Done),keyboardActions=KeyboardActions(onDone={calculateBmi()}),singleLine=true,modifier=Modifier.fillMaxWidth())
+                    } else {
+                        // Input untuk USC
+                        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                            OutlinedTextField(value=tinggiFt,onValueChange={tinggiFt=it},label={Text("Tinggi (ft)")},modifier=Modifier.weight(1f),keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Next),singleLine=true)
+                            OutlinedTextField(value=tinggiIn,onValueChange={tinggiIn=it},label={Text("Tinggi (in)")},modifier=Modifier.weight(1f),keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Next),singleLine=true)
+                        }
+                        Spacer(modifier = Modifier.height(16.dp))
+                        OutlinedTextField(value=beratLbs,onValueChange={beratLbs=it},label={Text("Berat Badan (lbs)")},leadingIcon={Icon(Icons.Default.MonitorWeight,"Berat Badan")},keyboardOptions=KeyboardOptions(keyboardType=KeyboardType.Number,imeAction=ImeAction.Done),keyboardActions=KeyboardActions(onDone={calculateBmi()}),singleLine=true,modifier=Modifier.fillMaxWidth())
+                    }
+                }
+            }
+
+            Spacer(modifier = Modifier.height(24.dp))
+            Row(Modifier.fillMaxWidth(),horizontalArrangement=Arrangement.SpaceAround){Button(onClick={calculateBmi()},modifier=Modifier.weight(1f).height(50.dp)){Text("Hitung",fontSize=16.sp)};Spacer(Modifier.width(16.dp));Button(onClick={reset()},colors=ButtonDefaults.buttonColors(containerColor=secondaryColor),modifier=Modifier.weight(1f).height(50.dp)){Text("Ulang",fontSize=16.sp)}}
+            Spacer(modifier = Modifier.height(32.dp))
+
+            // Kartu Hasil (Tidak perlu diubah)
+            AnimatedVisibility(visible=bmiResult!=null,enter=fadeIn(animationSpec=tween(500))+slideInVertically(initialOffsetY={it/2},animationSpec=tween(500))){Card(shape=RoundedCornerShape(16.dp),colors=CardDefaults.cardColors(containerColor=bmiColor),modifier=Modifier.fillMaxWidth()){Column(modifier=Modifier.padding(24.dp),horizontalAlignment=Alignment.CenterHorizontally,verticalArrangement=Arrangement.Center){Text("Hasil untuk $jenisKelamin, Usia $umur Tahun",color=Color.White,style=MaterialTheme.typography.titleMedium);Spacer(Modifier.height(8.dp));Text(if(bmiResult!=null)"%.2f".format(bmiResult)else {
+                ""
+            },color=Color.White,fontSize=48.sp,fontWeight=FontWeight.Bold);Spacer(Modifier.height(8.dp));Text(bmiCategory,color=Color.White,fontSize=20.sp,textAlign=TextAlign.Center,style=MaterialTheme.typography.bodyLarge)}}}
+
+            Spacer(modifier = Modifier.weight(1f, fill = false).padding(32.dp)) // Spacer fleksibel
+
+            // Tombol Keluar (Tidak perlu diubah)
+            OutlinedButton(onClick={navController.navigate("login"){popUpTo(0)}},modifier=Modifier.fillMaxWidth(),border=BorderStroke(1.dp,primaryColor)){Icon(Icons.Default.ArrowBack,"Keluar",tint=primaryColor);Spacer(Modifier.width(8.dp));Text("Keluar",color=primaryColor)}
+        }
+    }
+}