Rest api in android

[userand]

I am new to android studio working on simple login page

I want to check if a user exists in server by using rest api. I have done this earlier in Xamarin but not sure how to do it in android.

The user accepts email password entries and checks if user is registered or not. How can I do this?

 

[wseng92]

https://www.jackrutorial.com/2018/0...ervices-with-retrofit-2-android-tutorial.html

This may help.

 

[23tony]

I use Volley for working with REST APIs: https://developer.android.com/training/volley/

 

[Juraj Puchký]

Try this

public final class FromUrlHelper {

    public static JSONObject getJSONObject(String url) throws IOException {
        if (Constants.debug) Log.d("API Call", url);
        JSONObject jsonObject = null;
        try {
            jsonObject = new JSONObject(FromUrlHelper.getJSONFromUrl(url));
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return jsonObject;
    }
}

then call for example API like this

public class AuthService {
    private static AuthService ourInstance = null;

    public static AuthService getInstance() {
        if (ourInstance == null) {
            ourInstance = new AuthService();
        }

        return ourInstance;
    }

    private String currentSession;
    private boolean loggined;

    private AuthService() {
    }

    public boolean login(String email, String password) {

        if (!email.isEmpty() && !password.isEmpty()) {
            try {
                JSONObject result = FromUrlHelper.getJSONObject(Constants.serviceBaseUrl + "login?email=" + email + "&password=" + password);
                try {
                    int errorCode = result.getInt("errorCode");
                    if (errorCode == 0) {
                        this.currentSession = result.getString("sessionId");
                        loggined = true;
                        return true;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return false;
    }

    public boolean logout() {
        loggined = false;
        this.currentSession = null;
        return true;
    }
}

In Activity you can call this

AuthService authService = AuthService.getInstance();

if(authService.login("email","password")) {
    // do something
} else {
    // do something
}

In PHP API server it can look like this.

        $customer = $this->entityManager->getRepository(Customer::class)->findOneBy(['email' => $request->get('email'), 'password' => md5($request->get('password')), 'eshop' => $eshop]);
        if ($customer) {
            /** @var Session $session */
            $session = $this->getSessionFromCustomer($customer);
            if(!$session) {
                $sessionId = $this->createSession($customer);
            } else {
                $sessionId = $session->getCode(); 
            }
            $response->errorCode = self::ERR_OK;
        } else {
            $sessionId = null;
            $response->errorCode = self::ERR_AUTH;
        }

        $response->sessionId = $sessionId;

        return new JsonResponse($response);