Currency-Api by fawazahmed0 has been migrated to Exchange-Api, therefore updates to links and code have been made. For getting the exchange rates, the following changes have been made:
GET_URL:
from:
String GET_URL = "https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/latest/currencies/" + fromCurrency + "/" + toCurrency + ".json";
to:
String GET_URL = "https://cdn.jsdelivr.net/npm/@fawazahmed0/currency-api@latest/v1/currencies/" + fromCurrency+ ".json";
The new API does not support the /currencies/{currencyCode}/{currencyCode} endpoint, so please only use /currencies/{currencyCode} endpoint;
See here
Getting .getDouble(toCurrency)
from:
JSONObject jsonObject = new JSONObject(response.toString());
exchangeRate = jsonObject.getDouble(toCurrency);
to:
JSONObject jsonObject = new JSONObject(response.toString());
JSONObject fromCurrencyJson = jsonObject.getJSONObject(fromCurrency);
exchangeRate = fromCurrencyJson.getDouble(toCurrency);
A simple currency conversion application built using Java and Android studio, which allows users to convert between different currencies in real-time; currently the app uses 2 currrency conversion APIs, namely:
| Using Frankfurter | FrankfurterFragment.java |
|---|
Frankfurter-_Demo.mp4
| Using Exchange-Api | CurrencyAPIFragment.java |
|---|
CurrencyAPI_Demo.mp4
You can read on about how the usage of the APIs in the links provided above, but here's the general idea for both:
To get the latest exchange rates, use:
which will return:
{"amount":1.0,"base":"EUR","date":"2023-04-04",
"rates":
{"AUD":1.6154,"BGN":1.9558,"BRL":5.5121,"CAD":1.4641,
"CHF":0.9954,"CNY":7.5034,"CZK":23.418,"DKK":7.4513,"GBP":0.87333, and so on...}}
- Note: You can replace latest with any past date, such as 2012-05-01
To get the latest exhange rates for a specific currency (e.g. ZAR), add ?from=(currency code):
which will return:
{"amount":1.0,"base":"ZAR","date":"2023-04-04",
"rates":
{"AUD":0.08309,"BGN":0.1006,"BRL":0.28352,"CAD":0.07531,
"CHF":0.0512,"CNY":0.38595,"CZK":1.2045,"DKK":0.38327,"EUR":0.05144, and so on...}}
- Note: When a specific currency isn't given, the default currency is EUR
To get the latest exhange rates from one currency to another (e.g. ZAR to USD), add ?from=(currency code)&to=(currency code):
which will return:
{"amount":1.0,"base":"ZAR","date":"2023-04-04","rates":{"USD":0.05607}}
- Note: The from and to currencies cannot be the same, as it will result in no data being found:
https://api.frankfurter.app/latest?from=ZAR&to=ZAR
returns:
{"message":"not found"}
Use the following to get the list of currency codes and names:
https://cdn.jsdelivr.net/npm/@fawazahmed0/currency-api@latest/v1/currencies.json
which will return:
{
"1inch": "1inch Network",
"aave": "Aave",
"ada": "Cardano",
"aed": "United Arab Emirates Dirham",
"afn": "Afghan afghani",
"algo": "Algorand",
"all": "Albanian lek",
"amd": "Armenian dram",
"amp": "Synereo",
and so on...
}
To get the latest exhange rates for a specific currency (e.g. ZAR), add /(currency code) after /currencies:
https://cdn.jsdelivr.net/npm/@fawazahmed0/currency-api@latest/v1/currencies/zar.json
which will return:
{
"date": "2024-03-05",
"zar": {
"1inch": 0.104714,
"aave": 0.000761,
"ada": 0.144422,
"aed": 0.206403,
"afn": 4.875624,
"algo": 0.253741,
"all": 5.861798,
"amd": 21.832279,
"amp": 15.053744,
and so on...
}
}
- Note: You can replace latest with any past date, such as 2012-05-01
For both API usages, GETTING results uses this function:
public void getExchangeRateData(){
ExecutorService executorService = Executors.newSingleThreadExecutor();
Handler handler = new Handler(Looper.getMainLooper());
//performs a network request to retrieve the currency exchange rate
executorService.execute(new Runnable() {
@Override
public void run() {
try {
String GET_URL = "https://api.frankfurter.app/latest?from=" + fromCurrency + "&to=" + toCurrency;
URL url = new URL(GET_URL);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){ //successful
BufferedReader in = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();
while((inputLine = in.readLine()) != null){
response.append(inputLine);
}in.close();
//response.toString being the json of the api as a String
JSONObject jsonObject = new JSONObject(response.toString());
exchangeRate = jsonObject.getJSONObject("rates").getDouble(toCurrency);
progressDialog.dismiss();
}
}
catch (IOException | JSONException e) {
e.printStackTrace();
}
//updates the UI
handler.post(new Runnable() {
@Override
public void run() {
if (exchangeRate != 0 && !txtFromCurrency.getText().toString().equals("")) {
double input = Double.parseDouble(txtFromCurrency.getText().toString());
BigDecimal result = new BigDecimal(input * exchangeRate);
txtToCurrency.setText("" + result.setScale(3, RoundingMode.UP).toPlainString());
String currencyConversionRate = "1 " + fromCurrency + " = " + (1*exchangeRate) + " " + toCurrency;
lblCurrencyConversionRate.setText(currencyConversionRate);
}
else {
Toast.makeText(getContext(), "GET FAILED", Toast.LENGTH_SHORT).show();
progressDialog.dismiss();
}
}
});
}
});
}
and simply calling the function in your code with:
getExchangeRateData();
Alternatively, you can use AsyncTask<>
- NOTE: The default constructor in android.os.AsyncTask is deprecated, so it is not recommended
public class GetExchangeRateData extends AsyncTask<Void, Void, Double> {
//performs a network request to retrieve the currency exchange rate
protected Double doInBackground(Void... voids) {
double exchangeRate = 0;
try {
String GET_URL = "https://api.frankfurter.app/latest?from=" + fromCurrency + "&to=" + toCurrency;
URL url = new URL(GET_URL);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("GET");
int responseCode = httpURLConnection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){ //successful
BufferedReader in = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();
while((inputLine = in.readLine()) != null){
response.append(inputLine);
}
in.close();
//response.toString being the json of the api as a String
JSONObject jsonObject = new JSONObject(response.toString());
exchangeRate = jsonObject.getJSONObject("rates").getDouble(toCurrency);
progressDialog.dismiss();
}
}
catch (IOException | JSONException e) {
e.printStackTrace();
}
//return the exchangeRate, so that it's used in onPostExecute()
return exchangeRate;
}
//updates the UI
protected void onPostExecute(Double exchangeRate) {
if (exchangeRate != 0 && !txtFromCurrency.getText().toString().equals("")) {
double input = Double.parseDouble(txtFromCurrency.getText().toString());
BigDecimal result = new BigDecimal(input * exchangeRate);
txtToCurrency.setText("" + result.setScale(3, RoundingMode.UP).toPlainString());
String currencyConversionRate = "1 " + fromCurrency + " = " + (1*exchangeRate) + " " + toCurrency;
lblCurrencyConversionRate.setText(currencyConversionRate);
}
else {
Toast.makeText(getContext(), "GET FAILED", Toast.LENGTH_SHORT).show();
progressDialog.dismiss();
}
}
}
and calling this function with:
GetExchangeRateData getExchangeRateData = new GetExchangeRateData();
getExchangeRateData.execute();
or just simply with:
new GetExchangeRateData().execute();
There are definitely much better ways of making an application like this, such as using Retrofit with Gson for REST Api queries and json parsing, or using Kotlin's Coroutines, so this is just one example of how it can be done.