Tugas PPB - Aplikasi Konversi Mata Uang

Nama : Mavaldi Rizqy Hazdi

NRP : 5025211086

Kelas : Pemrograman Perangkat Bergerak D

    Tugas kali ini adalah membuat aplikasi konversi mata uang menggunakan kotlin pada android studio. Untuk pengayaan pada tugas kali ini adalah beberapa fitur tambahan pada aplikasi.

File MainActivity.kt :

package com.example.currencyconverterapp

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.font.FontWeight
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.currencyconverterapp.ui.theme.CurrencyConverterAppTheme

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

enum class Currency(val symbol: String, val rateToUSD: Double) {
    IDR("Rp", 0.000065),  // 1 IDR = 0.000065 USD
    USD("$", 1.0),        // Base currency
    GBP("£", 1.22),       // 1 GBP = 1.22 USD
    EUR("€", 1.08),       // 1 EUR = 1.08 USD
    CNY("¥", 0.14)        // 1 CNY = 0.14 USD
}

@Composable
fun CurrencyConverterAppScreen() {
    var amount by remember { mutableStateOf("") }
    var fromCurrency by remember { mutableStateOf(Currency.IDR) }
    var toCurrency by remember { mutableStateOf(Currency.USD) }
    var convertedAmount by remember { mutableStateOf(0.0) }

    val exchangeRates = listOf(
        "1 USD = ${(1 / Currency.IDR.rateToUSD).toInt()} IDR",
        "1 USD = ${(Currency.GBP.rateToUSD).toDouble()} GBP",
        "1 USD = ${(Currency.EUR.rateToUSD).toDouble()} EUR",
        "1 USD = ${(1 / Currency.CNY.rateToUSD).toDouble()} CNY"
    )

    Column(
        modifier = Modifier
            .fillMaxSize()
            .padding(16.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(16.dp)
    ) {
        Text(
            "Currency Converter",
            style = MaterialTheme.typography.headlineMedium,
            fontWeight = FontWeight.Bold
        )

        Column(
            modifier = Modifier.fillMaxWidth(),
            horizontalAlignment = Alignment.Start
        ) {
            Text(
                "Current Rates:",
                style = MaterialTheme.typography.bodyLarge,
                fontWeight = FontWeight.Bold
            )
            Spacer(modifier = Modifier.height(4.dp))
            exchangeRates.forEach { rate ->
                Text(rate, style = MaterialTheme.typography.bodyMedium)
            }
        }

        Divider(modifier = Modifier.padding(vertical = 8.dp))

        OutlinedTextField(
            value = amount,
            onValueChange = { amount = it },
            label = { Text("Amount") },
            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
            modifier = Modifier.fillMaxWidth(),
            leadingIcon = { Text(fromCurrency.symbol) }
        )

        Row(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.spacedBy(8.dp)
        ) {
            Column(modifier = Modifier.weight(1f)) {
                Text("From:", style = MaterialTheme.typography.bodyMedium)
                CurrencyDropdown(
                    selectedCurrency = fromCurrency,
                    onCurrencySelected = { fromCurrency = it }
                )
            }

            Column(modifier = Modifier.weight(1f)) {
                Text("To:", style = MaterialTheme.typography.bodyMedium)
                CurrencyDropdown(
                    selectedCurrency = toCurrency,
                    onCurrencySelected = { toCurrency = it }
                )
            }
        }

        Button(
            onClick = {
                val inputAmount = amount.toDoubleOrNull() ?: 0.0
                // Convert to USD first, then to target currency
                val amountInUSD = inputAmount * fromCurrency.rateToUSD
                convertedAmount = amountInUSD / toCurrency.rateToUSD
            },
            modifier = Modifier.fillMaxWidth()
        ) {
            Text("Convert")
        }

        Column(
            horizontalAlignment = Alignment.CenterHorizontally,
            modifier = Modifier.fillMaxWidth()
        ) {
            Text("Converted Amount:", style = MaterialTheme.typography.bodyLarge)
            Text(
                text = "${toCurrency.symbol} ${"%.2f".format(convertedAmount)}",
                style = MaterialTheme.typography.headlineMedium.copy(
                    fontWeight = FontWeight.Bold
                ),
                fontSize = 28.sp
            )
        }

        OutlinedButton(
            onClick = {
                val temp = fromCurrency
                fromCurrency = toCurrency
                toCurrency = temp
            },
            modifier = Modifier.fillMaxWidth()
        ) {
            Text("Swap Currencies")
        }
    }
}

@Composable
fun CurrencyDropdown(
    selectedCurrency: Currency,
    onCurrencySelected: (Currency) -> Unit
) {
    var expanded by remember { mutableStateOf(false) }

    Box(modifier = Modifier.fillMaxWidth()) {
        OutlinedButton(
            onClick = { expanded = true },
            modifier = Modifier.fillMaxWidth()
        ) {
            Text(selectedCurrency.name)
        }
        DropdownMenu(
            expanded = expanded,
            onDismissRequest = { expanded = false }
        ) {
            Currency.values().forEach { currency ->
                DropdownMenuItem(
                    text = { Text(currency.name) },
                    onClick = {
                        onCurrencySelected(currency)
                        expanded = false
                    }
                )
            }
        }
    }
}

@Preview(showBackground = true)
@Composable
fun CurrencyConverterAppPreview() {
    CurrencyConverterAppTheme {
        CurrencyConverterAppScreen()
    }
}

Tampilan Aplikasi pada Android Studio

Tampilan Aplikasi pada Emulator

*pengayaan pada aplikasi tersebut adalah menambahkan fitur swap currency yang bisa menukar mata uang yang ingin dikonversikan menjadi tujuan konversi dengan contoh rupiah ke dolla menjadi dollar ke rupiah dan untuk mengganti mata uang konversi bisa menekan nama mata uang dan akan terdapat menu dropdown pilihan mata uang nantinya.

Link Repositori : Github

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