Tugas 6 - Membuat Aplikasi Kalkulator Konversi Mata Uang
Membuat Aplikasi Kalkulator Konversi Mata Uang
Ricardo Supriyanto - 5025221218
Pada tugas pertemuan 6, saya diberikan instruksi untuk melakukan pengayaan dengan membuat aplikasi kalkulator konversi mata uang dengan menggunakan Kotlin. Project yang saya buat ini dapat melakukan konversi untuk total ada 10 mata uang yaitu:
- IDR (Indonesian Rupiah)
- USD (United States Dollar)
- JPY (Japanese Yen)
- EUR (Euro)
- GBP (British Pound Sterling)
- AUD (Australian Dollar)
- SGD (Singapore Dollar)
- CNY (Chinese Yuan)
- SAR (Saudi Riyal)
- MYR (Malaysian Ringgit)
Untuk melakukan konversi nilai tukarnya saya masih membuatnya dalam bentuk static dengan acuan konversinya berdasarkan Kurs Transaksi Bank Indonesia. Berikut merupakan contoh penggunaan aplikasi kalkulator Konversi Mata Uang tersebut:
Kode Program Modifikasi:
class NumberFormatVisualTransformation(
private val numberFormat: DecimalFormat = DecimalFormat("#,###")
) : VisualTransformation {
override fun filter(text: AnnotatedString): TransformedText {
val originalText = text.text
if (originalText.isEmpty()) {
return TransformedText(text, OffsetMapping.Identity)
}
val digitsOnly = originalText.filter { it.isDigit() }
if (digitsOnly.isEmpty()) {
return TransformedText(AnnotatedString(""), OffsetMapping.Identity)
}
if (digitsOnly == "0") {
return TransformedText(AnnotatedString("0"), OffsetMapping.Identity)
}
val formattedText = try {
numberFormat.format(digitsOnly.toLong())
} catch (_: NumberFormatException) {
return TransformedText(text, OffsetMapping.Identity)
}
val offsetMapping = object : OffsetMapping {
override fun originalToTransformed(offset: Int): Int {
val originalSub = digitsOnly.take(offset)
val formattedSub = try {
if (originalSub.isEmpty()) "" else numberFormat.format(originalSub.toLong())
} catch (_: NumberFormatException) { "" }
val separatorCount = formattedSub.count { it == ',' }
return offset + separatorCount
}
override fun transformedToOriginal(offset: Int): Int {
val formattedSub = formattedText.take(offset)
val separatorCount = formattedSub.count { it == ',' }
return max(0, offset - separatorCount)
}
}
return TransformedText(AnnotatedString(formattedText), offsetMapping)
}
}
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
enableEdgeToEdge()
setContent {
MoneyConverterTheme {
Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
CurrencyConverterScreen(modifier = Modifier.padding(innerPadding))
}
}
}
}
}
val exchangeRates = mapOf(
"IDR" to 1.0, "USD" to 16000.0, "JPY" to 105.0, "EUR" to 17400.0, "GBP" to 20100.0,
"AUD" to 10600.0, "SGD" to 11800.0, "CNY" to 2225.0, "SAR" to 4250.0, "MYR" to 3375.0
).toSortedMap()
val currencies = exchangeRates.keys.toList()
val currencyNames = mapOf(
"IDR" to "Indonesian Rupiah", "USD" to "United States Dollar", "JPY" to "Japanese Yen",
"EUR" to "Euro", "GBP" to "British Pound Sterling", "AUD" to "Australian Dollar",
"SGD" to "Singapore Dollar", "CNY" to "Chinese Yuan", "SAR" to "Saudi Riyal",
"MYR" to "Malaysian Ringgit"
)
@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun CurrencyConverterScreen(modifier: Modifier = Modifier) {
var amountInput by remember { mutableStateOf("") }
var selectedFromCurrency by remember { mutableStateOf(currencies.firstOrNull { it == "IDR" } ?: currencies.firstOrNull() ?: "") }
var selectedToCurrency by remember { mutableStateOf(currencies.firstOrNull { it == "USD" } ?: currencies.getOrNull(1) ?: "") }
var conversionResultText by remember { mutableStateOf<String?>(null) }
var detailedConversionText by remember { mutableStateOf<String?>(null)}
var isAmountError by remember { mutableStateOf(false) }
var fromDropdownExpanded by remember { mutableStateOf(false) }
var toDropdownExpanded by remember { mutableStateOf(false) }
val numberFormatTransformation = remember { NumberFormatVisualTransformation() }
fun performConversion() {
isAmountError = false
detailedConversionText = null
val amount = amountInput.toDoubleOrNull()
if (amount == null) {
if (amountInput.isNotBlank()) {
isAmountError = true
}
conversionResultText = null
detailedConversionText = null
return
}
if (amount < 0) {
isAmountError = true
conversionResultText = null
detailedConversionText = null
return
}
if (selectedFromCurrency.isBlank() || selectedToCurrency.isBlank()) {
conversionResultText = "Select currencies"
return
}
val rateFrom = exchangeRates[selectedFromCurrency]
val rateTo = exchangeRates[selectedToCurrency]
if (rateFrom != null && rateTo != null && rateFrom != 0.0) {
val result = amount * (rateFrom / rateTo)
val decimalFormatResult = DecimalFormat("#,##0.00####")
conversionResultText = "${decimalFormatResult.format(result)} $selectedToCurrency"
val oneUnitResult = 1.0 * (rateFrom / rateTo)
val decimalFormatDetail = DecimalFormat("#,##0.##")
detailedConversionText = "1 $selectedFromCurrency = ${decimalFormatDetail.format(oneUnitResult)} $selectedToCurrency"
} else {
conversionResultText = "Error: Invalid rate"
detailedConversionText = null
}
}
Column(
modifier = modifier
.fillMaxSize()
.background(Color(0xFFE0F7FA))
.padding(16.dp),
horizontalAlignment = Alignment.CenterHorizontally
) {
Text(
"Currency Converter",
style = MaterialTheme.typography.headlineMedium,
modifier = Modifier.padding(bottom = 24.dp),
color = Color.Black
)
Card(
modifier = Modifier.fillMaxWidth(),
elevation = CardDefaults.cardElevation(defaultElevation = 4.dp),
colors = CardDefaults.cardColors(containerColor = Color.White)
) {
Column(
modifier = Modifier.padding(16.dp),
verticalArrangement = Arrangement.spacedBy(16.dp)
) {
OutlinedTextField(
value = amountInput,
onValueChange = { newValue ->
val digitsOnly = newValue.filter { it.isDigit() }
if (digitsOnly.length <= 15) {
if (digitsOnly.startsWith("0") && digitsOnly.length > 1) {
amountInput = ""
isAmountError = false
conversionResultText = null
return@OutlinedTextField
}
amountInput = digitsOnly
isAmountError = false
conversionResultText = null
}
},
label = { Text("Amount") },
keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
singleLine = true,
modifier = Modifier.fillMaxWidth(),
isError = isAmountError,
supportingText = {
if (isAmountError) {
Text("Please enter a valid number", color = MaterialTheme.colorScheme.error)
}
},
visualTransformation = numberFormatTransformation
)
ExposedDropdownMenuBox(
expanded = fromDropdownExpanded,
onExpandedChange = { fromDropdownExpanded = !fromDropdownExpanded }
) {
OutlinedTextField(
value = selectedFromCurrency,
onValueChange = {},
label = { Text("From Currency") },
readOnly = true,
trailingIcon = { ExposedDropdownMenuDefaults.TrailingIcon(expanded = fromDropdownExpanded) },
modifier = Modifier.menuAnchor().fillMaxWidth()
)
ExposedDropdownMenu(
expanded = fromDropdownExpanded,
onDismissRequest = { fromDropdownExpanded = false }
) {
currencies.forEach { currencyCode ->
val fullName = currencyNames[currencyCode] ?: currencyCode
DropdownMenuItem(
text = { Text("$currencyCode - $fullName") },
onClick = {
selectedFromCurrency = currencyCode
fromDropdownExpanded = false
}
)
}
}
}
IconButton(
onClick = {
val temp = selectedFromCurrency
selectedFromCurrency = selectedToCurrency
selectedToCurrency = temp
},
modifier = Modifier.align(Alignment.CenterHorizontally)
) {
Icon(Icons.Filled.SwapVert, contentDescription = "Swap Currencies")
}
ExposedDropdownMenuBox(
expanded = toDropdownExpanded,
onExpandedChange = { toDropdownExpanded = !toDropdownExpanded }
) {
OutlinedTextField(
value = selectedToCurrency,
onValueChange = {},
label = { Text("To Currency") },
readOnly = true,
trailingIcon = { ExposedDropdownMenuDefaults.TrailingIcon(expanded = toDropdownExpanded) },
modifier = Modifier.menuAnchor().fillMaxWidth()
)
ExposedDropdownMenu(
expanded = toDropdownExpanded,
onDismissRequest = { toDropdownExpanded = false }
) {
currencies.forEach { currencyCode ->
val fullName = currencyNames[currencyCode] ?: currencyCode
DropdownMenuItem(
text = { Text("$currencyCode - $fullName") },
onClick = {
selectedToCurrency = currencyCode
toDropdownExpanded = false
}
)
}
}
}
}
}
Button(
onClick = { performConversion() },
modifier = Modifier
.fillMaxWidth(0.6f)
.padding(top = 24.dp),
enabled = amountInput.isNotBlank()
) {
Text("Convert")
}
if (conversionResultText != null) {
Card(
modifier = Modifier
.fillMaxWidth()
.padding(top = 16.dp),
elevation = CardDefaults.cardElevation(defaultElevation = 2.dp),
colors = CardDefaults.cardColors(containerColor = Color.White)
) {
Column(
modifier = Modifier
.padding(16.dp)
.fillMaxWidth(),
horizontalAlignment = Alignment.CenterHorizontally
) {
Text(
text = conversionResultText!!,
style = MaterialTheme.typography.headlineSmall.copy(
fontWeight = FontWeight.Bold,
),
textAlign = TextAlign.Center,
color = Color.Black
)
if (detailedConversionText != null) {
Spacer(modifier = Modifier.height(4.dp))
Text(
text = detailedConversionText!!,
style = MaterialTheme.typography.bodyMedium,
color = Color.Gray,
textAlign = TextAlign.Center
)
}
}
}
}
}
}
@Preview(showBackground = true, showSystemUi = true)
@Composable
fun CurrencyConverterScreenFinalPreview() {
MoneyConverterTheme {
Surface(modifier = Modifier.fillMaxSize()) {
CurrencyConverterScreen()
}
}
}
Link Repository Github: Tugas 6 - PPB
Demo Aplikasi:
Referensi:
https://www.bi.go.id/id/statistik/informasi-kurs/transaksi-bi/default.aspx
Komentar
Posting Komentar