Tugas 6 - Currency Converter

Currency Converter

MainActivity.kt

package com.example.currencyconverter

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import java.text.NumberFormat
import java.util.Locale

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            CurrencyConverterTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    CurrencyConverterApp()
                }
            }
        }
    }
}

@Composable
fun CurrencyConverterTheme(content: @Composable () -> Unit) {
    MaterialTheme(
        colorScheme = darkColorScheme(),
        content = content
    )
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun CurrencyConverterApp() {
    val exchangeRates = remember {
        mapOf(
            "USD" to 1.0,
            "IDR" to 16450.75,
            "EUR" to 0.93,
            "JPY" to 159.80,
            "SGD" to 1.35,
            "MYR" to 4.71,
            "SAR" to 3.75
        )
    }
    val currencies = remember { exchangeRates.keys.toList() }

    var amount by remember { mutableStateOf("") }
    var fromCurrency by remember { mutableStateOf("USD") }
    var toCurrency by remember { mutableStateOf("IDR") }
    var convertedAmount by remember { mutableStateOf<Double?>(null) }

    var fromExpanded by remember { mutableStateOf(false) }
    var toExpanded by remember { mutableStateOf(false) }

    fun convert() {
        val amountValue = amount.toDoubleOrNull()
        if (amountValue != null) {
            val fromRate = exchangeRates[fromCurrency] ?: 1.0
            val toRate = exchangeRates[toCurrency] ?: 1.0
            convertedAmount = (amountValue / fromRate) * toRate
        } else {
            convertedAmount = null
        }
    }

    LaunchedEffect(amount, fromCurrency, toCurrency) {
        convert()
    }

    Column(
        modifier = Modifier
            .fillMaxSize()
            .padding(16.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Text(
            text = "Konverter Mata Uang",
            style = MaterialTheme.typography.headlineMedium,
            modifier = Modifier.padding(bottom = 24.dp)
        )

        OutlinedTextField(
            value = amount,
            onValueChange = {
                if (it.matches(Regex("^\\d*\\.?\\d*\$"))) {
                    amount = it
                }
            },
            label = { Text("Jumlah") },
            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
            modifier = Modifier.fillMaxWidth()
        )

        Spacer(modifier = Modifier.height(16.dp))

        Row(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.SpfaceAround,
            verticalAlignment = Alignment.CenterVertically
        ) {
            Box(modifier = Modifier.weight(1f)) {
                ExposedDropdownMenuBox(
                    expanded = fromExpanded,
                    onExpandedChange = { fromExpanded = !fromExpanded }
                ) {
                    OutlinedTextField(
                        value = fromCurrency,
                        onValueChange = {},
                        readOnly = true,
                        label = { Text("Dari") },
                        trailingIcon = { ExposedDropdownMenuDefaults.TrailingIcon(expanded = fromExpanded) },
                        modifier = Modifier.menuAnchor()
                    )
                    ExposedDropdownMenu(
                        expanded = fromExpanded,
                        onDismissRequest = { fromExpanded = false }
                    ) {
                        currencies.forEach { currency ->
                            DropdownMenuItem(
                                text = { Text(currency) },
                                onClick = {
                                    fromCurrency = currency
                                    fromExpanded = false
                                }
                            )
                        }
                    }
                }
            }

            Spacer(modifier = Modifier.width(16.dp))

            Box(modifier = Modifier.weight(1f)) {
                ExposedDropdownMenuBox(
                    expanded = toExpanded,
                    onExpandedChange = { toExpanded = !toExpanded }
                ) {
                    OutlinedTextField(
                        value = toCurrency,
                        onValueChange = {},
                        readOnly = true,
                        label = { Text("Ke") },
                        trailingIcon = { ExposedDropdownMenuDefaults.TrailingIcon(expanded = toExpanded) },
                        modifier = Modifier.menuAnchor()
                    )
                    ExposedDropdownMenu(
                        expanded = toExpanded,
                        onDismissRequest = { toExpanded = false }
                    ) {
                        currencies.forEach { currency ->
                            DropdownMenuItem(
                                text = { Text(currency) },
                                onClick = {
                                    toCurrency = currency
                                    toExpanded = false
                                }
                            )
                        }
                    }
                }
            }
        }

        Spacer(modifier = Modifier.height(32.dp))

        if (convertedAmount != null) {
            val formattedResult = NumberFormat.getNumberInstance(Locale.getDefault()).apply {
                maximumFractionDigits = 2
            }.format(convertedAmount)

            Text(
                text = "Hasil Konversi:",
                style = MaterialTheme.typography.titleMedium
            )
            Spacer(modifier = Modifier.height(8.dp))
            Text(
                text = "$formattedResult $toCurrency",
                style = MaterialTheme.typography.headlineLarge,
                textAlign = TextAlign.Center,
                color = MaterialTheme.colorScheme.primary
            )
        } else if (amount.isNotEmpty()) {
            Text(
                text = "Masukkan jumlah yang valid",
                style = MaterialTheme.typography.bodyMedium,
                color = MaterialTheme.colorScheme.error
            )
        }
    }
}

@Preview(showBackground = true)
@Composable
fun DefaultPreview() {
    CurrencyConverterTheme {
        CurrencyConverterApp()
    }
}

Link github: https://github.com/fawwasaldy/currency-converter